100 Watt sub woofer amplifier.

Description.
This is the circuit diagram of a fully transistorized sub woofer amplifier that can produce an output of 100W.There are seven transistors including four in the output stage. The transistors Q1 and Q2 form the preamplifier stage. Transistors Q4 to Q7 form the output stage. Since no ICs are used the circuit is very robust and can be easily assembled on a general purpose PCB.

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Circuit diagram with Parts list.
100-w-subwoofer-amplifier-circuit

Notes.

  • The circuit can be powered from a +35V/-35V, 5A dual power supply.
  • Use a 100W, 12 inch sub woofer at the output.
  • All electrolytic capacitors must be rated 100V.
  • The transistor Q4 to Q7 must be fitted with heat sinks.
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729 Responses to “100 Watt sub woofer amplifier.”

  • Midhunmp says:

    Any problem when can i connect 10inch 4ohm subwoofr on this circut. If no problem how much power will get?

  • Midhunmp says:

    Can i use 25v 5amp ac to the circut?

    • Seetharaman says:

      Why this funny question? use supply voltage as recommended in the project. you can use a 25-0-25 5amps transformer with rectifiers smoothing capacitors and 6amp bridge rectifier (See 150 watts amplifier circuit for the power supply circuit). which will give you +35 -0- -35 volt DC for the amplifier.

  • Rituraz says:

    Hello, every one can i attach Q4 to Q7 in one heat sink and also give the perfect size of heat sink for this project thanks please reply I m waiting .

  • abubakar says:

    hello sir pls I have a question based on how to calculate the output power of this amp. U mention dat d relation of d output power is d square of voltage swing on d speaker leads divided by the impedence.pls sir I need explanations in detail. Thanks

  • Chris says:

    Hello,

    I managed to build the circuit and on an ossciloscope the readings look correct but when i connect a speaker instead it shorts on the negative end of the circuit. Any idea how to fix this? Any help would be greatly appreciated!

  • abubakar says:

    pls sir I made another circuit of dis same amp n I don’t want to use these 2n3773 due to insulation issue, pls sir can u tell me any 3 pin transistor Wich will b as good as d 2n3773 ? I tried using 2sc5200 but d sound isn’t as good as d 2n3773.
    n pls sir tell me d use of r1.tank u sir for ur time

  • guna says:

    sir
    want to be all all transistors please sent me i am all really getting transforms 35-0-35

  • abubakar says:

    thank u sir for d response my amp is working perfectly

  • lcd950 says:

    Does this circuit work?
    Did anyone make this circuit?

  • babu says:

    I have la4400 circuit what transformer it require for input power.
    please specify me that are there any connection wire for bass in la4440 and i will connect 2 woofer speakers as 80w with 8″,let me know if I am wrong that at first i need a transformer to connect to la4440,where to connect the volume,bass connection.
    here we have mac 8″ can i use.

    what type of woofer I must use name please.

    • babu says:

      or give me a name of circuit to connect 8″ to 12 ” woofer.

    • Seetharaman says:

      This IC is a car amplifier chip to handle car battery voltage . you can use 13.2 volt DC. A 0-9 volt transformer rated for 2 amps is more than sufficient. use a 3amp bridge rectifier and 4700uF 25 volt filter capacitor in parallel with 0.1uf 25volt ceramic disc capacitor. The IC will give 4.5 watt rms output into 4 ohms speaker.

  • jonsg says:

    Direkt auf. Es ist mehr informativ und leicht zu verstehen. Vielen Dank so eine schöne Leitlinie ……

    pa verstärker

    pa endstufe

    Mehrzonenendstufen

  • abubakar says:

    hi every 1 pls I have a question..pls I have a 2ohms 50watt subwoofer speaker can I use it wit dis amp

  • abubakar says:

    thank u sir seetharaman for d wonderful post n I thank u all for all ur comments. through d comments I was nw able to build my amp n it works really great. Thanks every 1 once again .i have nw started building d 150watt amp.sir may god reward u for all ur efforts

  • rohin says:

    hi, for pcb of this amp read my comment (rohin).

  • abubakar says:

    hi every one I have problem building dis circuit can someone help me out?pls

  • abubakar says:

    Pls can someone guide me on building dis circuit? I only have a humming sound @ d output.Whr must I have gone wrong?

  • harith says:

    sir please…im waiting for ur reply….pls any one….help….

  • alexander says:

    Hi i like this circuit,please give and send me a printed circuit board for this project.

  • Kannan says:

    how to noise produce to this ic

  • harith says:

    seetharaman sir,
    im an university student from Sri Lanka.im interested in this circuit….im going to build it.i have 28-0-28 transformer.can i use it? im going to use 4ohms 10inchs 200W subwoofer speaker.is there a chance to having a PCB desing of this cicuit..pls help…thanks.

  • saravanan says:

    please i want to know the full spare list and pcb layout

  • IH55T says:

    This amp works great. I was unable to find a 2N5494, but searching through the replies from the author identified similar replacements. The only problem I’m having is the presence of 0.177v at the output with no input. I’ll do a little adjusting on the bench to move the crossover point. Regardless, this works as published.

  • guna says:

    my mobil no 9843946968

  • guna says:

    want to all spears

  • krishna says:

    Hai sir, SEETHARAMAN. Does this amp needs preamplifier to amplify below 140htz signals or jst audio output any source will do, can u plz send me the circuit PCB,thanx for the reply.

  • guna says:

    seetharaman sir plase help with me my mail id gsgunasiva077@gmail.com

  • guna says:

    all spears data sheet and transister 3 how can test telme my mobil no 09843946968

  • guna says:

    please all spears list (35+)+(-35):70dc given onely for this project give me one sample assambled pdf or photo

  • Collins says:

    i need information on electronics

  • sravan says:

    how to add a volume controller to the circuit
    please please send me the circuit diagram to my email id please sir please,,,,,,,

  • RAVI says:

    CIRCUIT FOR 7.1 CHANNEL AUDIO. FOR 2 CHANNEL INPUT.
    ABOUT 300-400 WATT SUB WOOFER,& 50-100 WATT SPEAKERS.
    SIMPLE CIRCUIT FOR IT.
    PLEASE REPLY ME.

    • siva.R says:

      CIRCUIT FOR 7.1 CHANNEL AUDIO. FOR 2 CHANNEL INPUT.
      ABOUT 300-400 WATT SUB WOOFER,& 50-100 WATT SPEAKERS.
      SIMPLE CIRCUIT FOR IT.
      PLEASE REPLY ME.

  • Kwadwo Boateng says:

    Sir, after building the 100w subwoofer power amplifier how will it look like. Thanks

  • natarajan says:

    hello sir, i want 5.1 home theater circuit digram pleas

  • omer says:

    150 watts subwoofer amplifier circuit added here
    visit
    www . it-tronics . blogspot . com

  • Guna says:

    Transister how cane checked .? Bass callactor emater and npn pnpn

  • Guna says:

    Yoused for 35-0-35 volt transformer dc circuit diode and capacitor witche valvu yoused an this circuit

  • cooool says:

    hi sir I made this circuit on breadboard only speaker humming there is no output sir please help me sir my circuit is till on table

  • Guna says:

    100w amplifier connected load 8″ speaker how much sound came ? Input volt 35 -0-35vdc 5amps

  • Guna says:

    680 ohm how? watt

  • Guna says:

    47 k is how ? Watt

  • Guna says:

    100w amp traied this projact please help all capacitor valvu 100v reastor valvu some miss ing

  • Harry Cat says:

    I have a question about the required power supply for this amp circuit..
    I currently have a 36-0-36 5 amp per side transformer that will deliver +-35 volts DC after going through the 5 amp bridge rectifier. I also have one each per side 4700MFD 63 volt Electrolytic Cap and one 2.2MFD 60volt Poly Cap per side..
    Is this power supply setup too much for the circuit to handle or do I need to by a 25-0-25 transformer to keep from over loading the circuit?
    A 25-0-25 transformer that delivers 5 amps per side is extremely expensive..
    I could build my own transformer but getting the E I type silicon Iron sheets is impossible since I live in America. America doesn’t make anything or have anything to make a transformer except magnet wire only.
    Thanks

  • normal says:

    Hi sir I transistor 2n5294 and only 5294 are same? Please reply me

  • normal says:

    Hi sir I transistor 2n5254 and only 5294 are same? Please reply me

  • vitthal says:

    Hi Sir,
    please sir,
    Can you please send me a simple home theatre circuit using Subwoofer. with material list

  • Janaka says:

    Hi Sir,
    This one has no Filter circuit. Right.? So if we connect this to any input other than SUBWOOFER OUT PUT of a Hi FI set up we should have a filter circuit connected to this first. Right sir.?
    Forgive my Ignorance. How do I determine the BCE pins of Transistors. I know how to figure out BCE of C828 and D400 transistors but is it the same for these Transistors too.?. All Transistors have the BCE pins in the same way or are they different depending on PNP or NPN. Please explain..Sir..

    • Seetharaman says:

      Hi Janaka if you have a subwoofer output from your dvd player, can be connected directly to this amplifier. If you have only stereo information(left and right channel information) then you have connect through a sub woofer filter bothe channel information to make it as 2.1 information. 2 is left and right .1 is subwoofer signal.
      Transistor lead configuration will differ for each manufacturer, hence you have to consult their catalog. the following link is the best filter
      http://sound.westhost.com/project48.htm

  • ASHISH KUMAR says:

    HI,
    SIR,
    KINDLY SEND ME A CIRCUIT OF 200 WATT RMS SUB-WOOFER AMPLIFIER, ITS OPERATING CURRENT AND VOLTAGE, PART LIST AND PCB.

  • ajithsoman says:

    its working..well..

  • Janaka says:

    Sir, Forgive my Ignorance. How do I determine the BCE pins of Transistors. I know how to figure out BCE of C828 and D400 transistors but is it the same for these Transistors too.?. All Transistors have the BCE pins in the same way or are they different depending on PNP or NPN. Please explain..Sir..

  • Janaka says:

    Hi Sir,
    This one has no Filter circuit. Right.? So if we connect this to any input other than SUBWOOFER OUT PUT of a Hi FI set up we should have a filter circuit connected to this first. Right sir.?

  • SUBRATA KARMAKAR says:

    Can you please send me a simple 2.1 home theatre circuit using Subwoofer.

  • Bipro says:

    pleas give me the pcb of this circut.

  • LOGANATHAN G says:

    hi sir
    can you please give me the PCB layout of this circuit..

  • Janaka says:

    Please let me know this 100 watts are PMPO or RMS???

    • Seetharaman says:

      Hi Janaka it is 100Watts RMS power at <1% distortion into 4 ohms load with plus minus 32 volts DC and into 8 ohms load with plus minus 45volts DC supply.

  • rohin says:

    hi, for pcb of this beautiful amplifier visit at my blog http://www.123456789wertt.blogspot.in/

    • vicky says:

      thanks for pcb…did u check that ckt by giving connections>>>>?

      • rohin says:

        hi vicky, i made 6 amp on this pcb.pcb is working 100%.alternative list of transistor.bc 108 or bc 109 or bc 547 and 2n 6107 or a940 and 2n5296 or 2n 5294 or c2073.2n3773 or 2n3055 or c 5200 or mjl 21194.

    • Alfian says:

      Hi….. Rohin
      how to add volume control in this subwoofer…?

      • rohin says:

        hi, you can use any tone control circuit.for a subwoofer you need sub filter circuit otherwise you can add a tone to control volume that is your taste.

      • Seetharaman says:

        August 9, 2011 at 8:36 am
        Hi Shbham Use a 100k log potentio-meter(three tags), preferred but if not available use 100k lin (not rheostat- 2 tags only). connect center of the potentiometer to C1. one end of the potentiometer to common(ground). Connect input between both the end of the potentiometer such that input signal ref is connected to common and actual signal is connected to other end of the potentiometer.

  • Petar says:

    Hey there im a student at chisholm catholic college and am working on an engineering project.Just wondering if you have a diagram of a circuit for a 100 Watt sub woofer amplifier that can run off 12 volts.

  • Lonely Eagle .. says:

    Sir can i get your pcb lay-out !? So that i can build it at my own ..

  • RHOL says:

    sir, can i have the design of pcb layout…thanks!!!

  • Ch.shashank says:

    sir i want to design this ckt please if u have some time please send me your pcb layout sir please i want to try it for my project sir…….

  • safder says:

    hi sir
    can you please give me the PCB layout of this circuit..

  • abdul says:

    Sir i am used for 100 watts subwoofer . Which capacitor use?

  • srinivasan says:

    dear sir,

    i am using this amplifier for my sub-woofer with KFC W3013 ken wood 12″ Woofer(1200 W peak 450 W RMS) , and i am using sub-woofer filter also i/p of this amplifier , 24-0-24 5A Ac transformer,but when i raise the volume,i am getting poor effect( like vibration DURRRRRR – sorry i don’t know how to explain)with base effect ,i could not understand, what is the real problem , woofer also more than enough wattage rated with proper size enclosure ,transformer 5A rating . any body can please advice me .

    thanks in advance

    • sino says:

      Hi, please check the grounding.power supply grounding ,volume control grounding and speaker ground should be connected to different ground points. volume gnd should be away from power supply gnd point .

  • gayan says:

    can u please send me the list of components by a mail please .

  • ermsk8er says:

    Thanks!

  • ermsk8er says:

    Thanks for sharing your design, sir. Can u send me ur pcb layout for this circuit. Thanks again! My email – erm.sk8er@yahoo.com

  • migs says:

    dear sir..

    i want to try your 100wat subwoofer as my project in school.. can u sent it to me ur PCB layout and so with the components… thanks in advance..

  • Rahul Cinal says:

    Dear Sir,
    Please send me the parts details of this circuit board & thanks for the idea.

    Thanks & Regards,
    Rahul Cina
    Data Processor of Godrej & Boyce Mfg. Co. Ltd.

  • manish says:

    hiii can u plzz tell me whats d difference between a subwoofer amplifier and a normal 150 WATT amplifier…..
    can anyone plzz explain….
    plzz hlp..me i m making d 150 WATT amplifier

    • Janaka says:

      Sub woofer is a Mono Amp giving only the Bass ( Mostly) to a one Speaker. A Normal Stereo Amp is giving both Bass and treble to two Speakers. In a Sub woofer A Filter circuit also used to filter the sound so Treble can be minimized giving only the Bass. but again in a Normal Stereo Amplifier Filtering is not required. It gives both Bass and Treble equally.

  • manish says:

    Hi can anyone plz temme is ther any difference between a subwoofer amplifier and a normal amplifier I am going to build the 150watt amplifier how can I interface a subwoofer??? Plzzzz hlp me
    Thanks in advance……

  • S.alam says:

    hi
    can anyone please give me the PCB layout of this circuit
    “alamisdecent@gmail.com”

    thanking you..

  • omer says:

    hi sir seetharaman….

    i have a question in my mind that is dre any way to increase the output power of this amplifier?

    here’s one thing in my mind that if i use multiple transistors (2n3773′s) at the ouptput then is there any chance of increment of the output of this amplifier???????

    if yes then what will b the supply ratings??
    n how much i can increase the power by doing this modification ?

  • Kennedy Marquez says:

    Thanks for the circuit. Sir I want to do it. can you please help me, just send to my email the full detailed of the circuit including the part lists(also the electronic components connection), the speaker and the power supply that I will going to used. thank you very much sir.

  • pradipta pal says:

    i want to do a 5.2 channel surrounding home theater without programmer i.c. I want to know a circuit design using tl 084. But the i.c is not available where i live. Plz anybody give substitiude i.c design.

    • rohin says:

      hi pradipta pal,you can use lm324 in place of tl084 without any tension and it is available all electronics shops.best of luck

  • YED KRiz says:

    SEETHARAMAN sir tank u for this circuit…..
    sir can u please mail me the pcb layout of this circuit….

    SEETHARAMAN Sir,AS A FEED BACK,CAN YOU ATTACH THE PCB LAYOUT OF THIS CIRCUIT.BECAUSE EVERY ONE HAS DIFFICULTY TO FIND THE PROPER PCB LAYOUT OF THIS CIRCUT.IF YOU DO THIS,IT WILL BE A VERY HELP FULL FOR PEOPLE LIKE US

    • rohin says:

      HI YED KRIZ,don’t take tension about the pcb.i will make for you on 7th oct. on sunday.i will make it without power supply capactor and diodes.i want to help you all new people in electronics. seetharaman sir is great and they are doing a nice job for us.thank you n love u all

  • prakash says:

    Hi… can we use torroidal transformer…?

  • prakash says:

    Hi… plz provide the transformer specification and as well as recommended power supply circuit to the amplifier.

    • seetharaman says:

      September 9, 2012 at 9:43 am
      Hi Pramod you cannot, as 36-0-36 AC at transformer secondary will produce a DC of +51 – 0 – -51 volts. it will blow all the components. The maximum allowable transformer secondary rating is 25-0-25 volt RMS AC @3Amps, will develop around +36 -0- -36 volts DC best suited for this amplifier.

    • rohin says:

      hi everyone,transformer for this circuit is 26-0-26 ac.it gives 40-0-40 dc.for example ac i volt when we convert it to dc it become 1.4142volt dc.

  • sai ram says:

    sir please replay me fast sir i am waiting for u replay

  • sai ram says:

    sir i have center transformer which has teo outputs the outputs goes lie this 24-0-24 12-0 5amps can i use this transformer in this circuit bcoz 24+12=36v

  • omer says:

    for a complete PCB layout of this amplifier circuit just mail me …

    shining_star_12351@yahoo.com
    or
    engr.omer19@gmail.com

  • PRAMOD MANUJA says:

    THANKS SIR I GOT A BIG KNOWLEDGE FROM THIS CIRCUIT& I BUILT IT. IT IS WORKING.THANKS AGAIN ! I USED B857 FOR 2N6107,D313 FOR 2N5294.

  • omer says:

    hey guys, if any one is new to electronics and want to build or design his/her own sound systems then please visit my blog.
    containing all step by step instructions for building any kind of amplifier. I have started it from the very basic.

    http://www.universalcircuits.blogspot.com

    i have started this platform for all people who find their great interest in making their own circuits.

  • PRAMOD MANUJA says:

    SIR CAN I USE +36V / 0V / -36V 5A TRANSFORMER ?

    • seetharaman says:

      Hi Pramod you cannot, as 36-0-36 AC at transformer secondary will produce a DC of +51 – 0 – -51 volts. it will blow all the components. The maximum allowable transformer secondary rating is 25-0-25 volt RMS AC, will devolop around +36 -0- -36 volts DC best suited for this amplifier.

  • omer says:

    hey guys, if any one is new to electronics and want to build or design his/her own sound systems then please visit my blog.
    containing all step by step instructions for building any kind of amplifier. I have started it from the very basic.

    http://www.all-audio-amplifiers.blogspot.com

    i have started this platform for all people who find their great interest in making their own circuits.

  • mahesh says:

    hi Seetharaman sir , i have 12 -0 -12 tx & give me the pcb design ckt of 60W Subwoofer. Thanx

  • PRAMOD MANUJA says:

    sir please send me replacement for all of this transisters.if i use this replacement do i have to change transformer or any other part ?

  • Ofon udo says:

    I need a circuit diagram of a 100watt audio amplifier with four B688 and four D718 transistor

  • Suresh says:

    Any one can sent me the pcb design plz?
    This is my email.:Sures1997@gmail.com

  • Isaac Asante says:

    I never use before,i am now going to try.

  • sai ram says:

    sir this subwoffer gives only subwoofer effect what abt left and right speaker how to connect it in this circuit

    • Seetharaman says:

      Hi Sairam Sub woofer is the the one which reproduces below 140Hz. This cannot be heard but can be felt by body hence no directivity. One amplifier with suitable low pass filter getting the signal from both left and right channel information with a sub woofer box will take care of it. For left and right speakers you require a stereo amplifier to amplify left and right signal seperately and reproduce, which will give you the directivity.

  • Seetharaman says:

    Hi Predencio you can use.

  • Prudencio G. Peritos Jr. says:

    sir
    can i used 24v-0-24v 6A for this circuit?

  • Prudencio G. Peritos Jr. says:

    hello sir can i used 24-0-24v 6A for this 100 watt subwoofer amplifier?

  • ishan1211 says:

    Sir,
    I am waiting for your answer, my circuit is still on the table. Pls reply

  • Punam Pradhan says:

    I have all the required Parts for the 100 watt sub woofer amps. but without PCB I am little confused.If any one can send me PCB design will be great help for me.

    Thanks,

    Punam Pradhan

  • rohin says:

    hi dear seetharaman sir , this amp is good and its still working without any probelm. miss you and love you. you are one of the favorite person in my list.

  • krishna says:

    sir,
    Can u send me a circuit for 60w subwoofer circut

  • ishan1211 says:

    Sir,
    I made this circuit but power both transistor 3773 heatup withing few seconds, speaker is humming without a signal, voltage between speaker about 10V. sir what would be the solutions?

  • ishan1211 says:

    Sir,
    My transformer provide 35v, 0v, 35v. so how can i create +35v , -35v ?

  • sebin jacob says:

    Seetharaman sir,

    I am using this amplifier for the last one year.It is working fine and i am satisfied.You helped and guided me a lot during this project.Hope you r doing good.Always remembering your help.

    SEBIN JACOB

  • NASA says:

    hellow sir
    i want to made a simple circuit with woffer and spekar so how..??? give me daigram pls….. its my project nd by net i get a circuit but its very complicated so…..

  • Pankaj says:

    hello sir please tell me how can I add a bass and volume controller to this circuit?????

  • Pankaj says:

    thanks a lot sir now I had made the changes and my circuit is working perfectly……
    thanks again for your support and feedback.

  • Seetharaman says:

    Hi Pankaj you have to use 2N5294 only. since 2N5296 VCEO is only 40 volts. With DC + – 28 volts the circuit should work but will give you lesser wattage. With 18 volt transformer you will get only + – 25volts. try to use recomended components or else the circuit may not give satisfactory results. The component values are calculated for a particular supply voltage a deviation of a maximum of 10% only allowed.

  • Pankaj says:

    sir please help me my circuit is not working….

  • kanagaraj.s BE says:

    sir i want 24v single supply power amplifier circuit(nearly 30v) equivalent
    to stk 4392 plz send me

  • Pankaj says:

    thanks a lot sir but in my location there is no such person.
    is it possible that it is due to my power supply because Iam using +/-28 volt power supply?????
    In the power supply Iam using 18-0-18 volt 5 amp transformer.
    and sir Iam not able to find 2N5294 so Iam using 2N5296 is it possible that the problem is due to that transistor??????

  • Seetharaman says:

    Hi Pankaj check all your wirings transistor pins and diode polarities value of resistances capacitor polarities etc. Still if you are not in a position to fix the problem and if you are new to building of high power audio projects, please approach any knowledgeable electronic hardware engineer nearer to you, by physically viewing and analysing your assembly.

  • Pankaj says:

    Sir My circuit is not properly.Iam using a +/-28 volt 5A power supply.But my speaker is only humming doesnt produce any sound and the transformer starts burning after few seconds.Please suggest me appropriate solution…..

  • SYED OMAR MASOOD says:

    circuit diagram of ups 500w

  • SYED OMAR MASOOD says:

    I want a complete ups circuit diagram and also a line follower robot circuit diagra…

  • Pankaj says:

    hello sir could you please give me the board layout of this amp. Because I,am new to electronics field and not able to make a proper board layout.Please help me
    my email:-pankaj2892@gmail.com
    Thanks

  • Austyno says:

    Inverter circuit diagram output 220w

  • jocel says:

    hai sir, my hobby is electronics all my knowledge came from my own interest and patience i didnt go to school. im studying electronics on my own. and its hard. so please help me sir.
    may i ask you the formula of this amplifier and i will study it and give tips in designing audio amplifier.. thank you sir and God bless u all my fren… this is my email: http://www.jeoceltangdol@yahoo.com

  • seetharaman says:

    Hi Srinivasan you can connect it only through bass boost amplifier low pass filter is not required.

  • P.Srinivasan says:

    Hi seetharaman sir , i am using our low-pass-filter-for-sub woofer before this circuit ( for direct audio out ). can i add base booster pre amplifier with lowpass filter ,
    if i can , where i can connect low pass filter input or output stage ?

  • bal wolley says:

    I am building an infrasound device to be used in a spook house for a chairity fund raiser and need to build an amplifier that will not filter out the signals below 22hz. How do I configure this amplifier circuit to do this?

  • seetharaman says:

    Hi Srinivasan The recorded MP3 CDs are compressed ones they will produce only a flat response(but for the few genuine good quality recording). You can add a bass boost pre amplifier before feeding it to this amp. In the net you get plenty of such bass booster schematics use on of them.

  • P.Srinivasan says:

    Hi seetharaman sir, when i using orginal dvd or audio cd , i am getting good base effect form this amplifier , but when i using mp3 cd’s i could not get same effect even half also , what is the reason ??? what can i do for that ?

  • Sujeesh says:

    Hello sir,i want a tone controll seprator circuit that allows low freequency into this power amp’s input filter and other tones are seprate for other audio amp.please help me sir,
    my mail id is sujeejackson@gmail.com

  • techera says:

    wonderful

  • dav says:

    interesting.

  • Ajith says:

    sir..what type of heat sink the ,main transistor need…can i get an image of assembled this circuit..
    ajithsmn@gmail.com

  • shyam singh says:

    can i get the pcb lawout

  • seetharaman says:

    Hi Srinivas the relation for the output power is square of the voltage swing available across the speaker leads divided by the impedance of the speaker.
    The budget cost including power supply, with standard trasformer, good heat sink, PCB and with good quality low noise components will be around INR1200/-

  • P.Srinivasan says:

    Dear seetharaman sir,

    if input voltage is decrease below 30-0-30 then out put RMS power will decrease ????

  • sai ram says:

    sir wats the budget cost of this circuit

  • Ajith says:

    sir,i too think so..but i use a cooling fan also with it…does it can compansate it…??

  • Seetharaman says:

    Hi Ajith it should not become too hot it looks like your heat sink is insufficient, try using a bigger extruded alloy heat sink.

  • Ajith says:

    sir.,now my amp works fine..but .when it works for almost half an hour ,the 3773 s get hot as much as ,cant to touch it…
    Is it a problem or its usual??pls help me. .sir.,

  • rohin says:

    hi to everyone, i want to tell you that for good quality sound and high bass 2n 3773 is responsible. it made by many company like bel,toshiba,motorolla,china and local in delhi. you will get bad low quality in local and china made transistor of cost of 5 Rs. rest are cost of estimatly 50 Rs. so purchase right one for circuit.

  • Seetharaman says:

    Hi Harshit use our 150 watts amplifier with suitable sub woofer filter
    http://www.circuitstoday.com/150-watt-amplifier-circuit

  • ishan1211 says:

    Sir,
    I have bought every equipment’s in this circuit. my next challenge is design PCB diagram. it’s not very easy for me. if you can send me PCB diagram. Thanks
    E-mail: ishan1211@gmail.com

  • P.Srinivasan says:

    Dear Mr. seetharaman , can u please give me two channel switching circuit using audio signal detection that means one line normal condition , if 2nd channel audio signal detected 2 channel to be active and first channel to be disconnected.

  • harshit says:

    sir i want to make a subwoofer for computer please send send me a circuit of 150watt which is not so costly

  • rohin says:

    hi to everyone, i love this website and dear mr. seetharaman. this is not only a place where we make these projects and discuss. how we love each, to each other and respect. i am very empressed by you all and specially mr seetharaman. now i will give you, all my experience.May God bless you all.best wishes for holi.

  • kutty says:

    friends…i have a stereo amplifier..i would like to set a sub woofer to that amp..i got a sub board and i connected it…but the beat is very low..may i give the output of sub board to stk 4141 board and amplify it…my power supply is 12 0 12 3A transformer…is it enough..or any other reasons????

  • ALAM says:

    i have two speakers (max 70 watt, 6ohm)both
    i need a sub woofer amplifier design
    suggest me a design that produce heart pumping sound my mail is
    ((( alamisdecent@gmail.com )))

  • Ajith says:

    sir..can i??

  • Seetharaman says:

    Hi Alam Both are very important. a good amplifier with lousy speaker or a distorted low power amplifier with very good speaker is of no use. A rigid sealed enclosure is a must. the speaker can be little less rated than the amplifier for the best performance. A 100 watts @ <1% distortion amplifier with say 80watts 12" speaker or 40watts 2 nos 8" speakers in rigid sealed enclosure can give high quality thumping bass.

  • ajay says:

    hey rohin
    thanks a lot for ur time and advice .

  • Ajith says:

    thanks seetharam sir…i got ur mail.
    Sir.have a ups transformer with rating 6-0-6 />20amps[500va].can i use this transformer to obtain 25-0-25 /5A.,.

  • rohin says:

    yes, ajay my brother i am here to help you. i want to chat with you . i quicky solve your probelm . my no. is 9855427506. it is difficult to solve this by comments

  • alam says:

    can any one tell me that who is responsible for the high bass effect
    1 amplifier or
    2 speakers

  • ajay says:

    hey rohin
    can u help me with the circuit I have almost built it twice but still its not working.I have checked the transistor they are connected in right way .I have used c3 6.8uF 63v instead 0f 10uF and transistors bc547 instead of bc108. is it because of the bc547??? all my capacitors are rated above 100v except c3.

  • ajith says:

    sir..my e mail id is..
    ajithsmn@gmail.com
    thanks.

  • Seetharaman says:

    Ajith send your email id i will give ou a detailed checklist

  • ajith says:

    sir..i made this circuit..but its does not give any outputs..
    When i connected to supply both 3773 get heats up within seconds..how can i test the circuit…..sir,what may be the problem?pls help me…i made this circuit for my mini project at my clg…..

  • P.Srinivasan says:

    thanks for your confirmation

  • Seetharaman says:

    HI SRINIVAS HE IS CORRECT THE SAME I HAVE MENTIONED MUCH EARLIER ALSO.

  • P.Srinivasan says:

    Dear Mr. seetharaman , as on rohin comment C2 polarity is wrongly connected
    , its true ??

  • rohin says:

    TO making this circuit, you should know about the E C B of every transistor.if you conected it wrong then circuit will not work at all.2n 6107 and 2n 5294 , keep them front of your eyes( black side of the transistor , where is no. showing) left pin is base , middel pin is collector and the third pin is emitter.In 2n 3773 , keep it pin sides in front of your eyes and you will find that pins are much closer to one hole than comparesion to other hole , keep that hole to left which is much closer to pins and then upper pin is emitter and below pin is base and case is collector. you can use 5296 or 5294 or 2073.you can use bc108 or bc 109.check proper wiring it should be same as diagram showing.if everthing is ok. you should check your all transistor . you can check bc108 by multimeter hfe ports and its C B E too. for npn transistor, put postive on base and negetive to emitter, it showing 600or 700 ohm resistance like diode and negetive to collector it showing same as emitter but when negetive on base resistance should be high for both emiiter and collector. and to check pnp , it same like the npn only difference of postive and negetive leads

  • rohin says:

    hi to everyone, i want to tell you all that amplifier works fine and this circuit is high bass than 5.1 home theater. i already built it with the help of dear mr. seetharaman. he is a great person.there is one mistake in this circuit that c2 polarty is wrong conected. so kindly change it . otherwise there is everything allright. while making this circuit i face some probelm and i want to share it with you all.

  • manigandan says:

    i want circuit

  • seetharaman says:

    Hi Ajith a subwoofer amplifier is an amplifier with a good low frequency response and with a power of not less than 40Watts RMS at less than 1% THD & with good transient response.

  • ajay says:

    hey
    can anyone help me with this circuit please…. i have built this circuit but its not working .all my capacitors are rated above 100v except c3 which is 63v.used 2n5296 instead of 2n5294. c1 is 0.47mfd instead of 0.22mfd tested it with a 24-0-24 supply.Rest all are same components. what should I check in the circuit..

  • faishal says:

    sir tolong kirim ke email saya pcb layoutnya.trims

  • Ajith says:

    sir ,what is the difference between an ordinary amplifier and amplifier designed for subwoofers??

  • Awn Abbas says:

    Hi Sir seetharaman i want pcb design of this 100w sub woofer amp PLz Send me On my ID Plz Plz Plz

  • Seetharaman says:

    Hi srinivasan if output voltage is positive with respect to common zero reduce either R11 or 12 to next lower preferred value. if negative increase it to next higher preferred value

  • P.Srinivasan says:

    how to adjust the R11 or 12 value , value to be increase or decrease

  • regor wall says:

    gud day sir seetharaman ..! i want to build your featured subwoofer amp..can i ask for the pcb layout of this amplifier..pls email me..Wall.regor@yahoo.com.

    thanks in advance sir.. your reply is highly appreciated..

  • seetharaman says:

    Hi Srinivasan check the DC voltage across speaker. It should be zero. if not one may draw more current than the other. you may adjust the value of R11 or 12 till it becomes minimum, the problem is due to mismatch in the components.

  • P.Srinivasan says:

    hi seetharaman sir this amplifier working fine , but output one transistor heating more than other transistor . i am using 30-0-30 v Dc 5A

  • rohin says:

    hi seetharaman sir, you are great and i thanks to you very much for help me. now my circuit is working fine.

  • r.vijay dhas says:

    i want pcb design of this 100w sub woofer amp my id r.vijayadhas@gmail.com

  • Seetharaman says:

    Hi Rohin check your email for my detailed reply.

  • rohin says:

    circuit is not working for me

  • rohin says:

    i am wiating your help and response

  • rohin says:

    my mail id is rohin.sharma83@yahoo.com some one help me

  • rohin says:

    dear sir,i made this circuit but not working when i connect it to woofer R15 is burning please help me as soon as.waiting for your reaply

  • J S Nagaraj says:

    Please confirm me wether this blog is genuine or wether this website is a fake

  • P.Srinivasan says:

    Dear sir , i planned to keep the this amplifier kit ( including power supply unit ) into the sub woofer enclosure inside, there is any problem if woofer and transformer in one box ,

    SUB BOX DIMENSIONS KFC-W3013
    Sealed box volume 35.4 Litres
    Sealed Box Dimensions 475 x 362 x 299mm (19mm thick MDF)(WxHxD)
    Vented box volume 56.6 Litres
    Vented Box Dimensions 590 x 362 x 355mm (19mm thick MDF)(WxHxD)
    Port dimensions (labyrinth) (W x H x L) 38 x 324 x 546mm

    please advise me

  • J S Nagaraj says:

    Mr. Srinivasan, there won’t be any considerable problem because most of the
    2.1 channel amplifiers contain transformers in them but try to keep a bit far from the speaker.Try to shield the transformer if not leave it as it is.

  • J S Nagaraj says:

    Sir, Mr.Seetharaman
    I am not finding an exact input buffer and tone-control circuit for
    my STK4141 II amplifier board. Please help me with TOTAL amplifier circuit of the same.
    Thanking you,
    J S Nagaraj.

  • P.Srinivasan says:

    Dear sir , i planned to keep the this amplifier kit ( including power supply unit ) into the sub woofer enclosure inside, there is any problem if woofer and transformer in one box ,

    SUB BOX DIMENSIONS KFC-W3013
    Sealed box volume 35.4 Litres
    Sealed Box Dimensions 475 x 362 x 299mm (19mm thick MDF)(WxHxD)
    Vented box volume 56.6 Litres
    Vented Box Dimensions 590 x 362 x 355mm (19mm thick MDF)(WxHxD)
    Port dimensions (labyrinth) (W x H x L) 38 x 324 x 546mm

    please advise me

  • Seetharaman says:

    Hi Srinivasan you can use. once amplifier distortion sets in above 100watts the speakers voice coil will be damaged over prolonged operation.

  • P.Srinivasan says:

    can i use 4 ohm kenwood woofer (400w rms power )for this circuit ????

  • Seetharaman says:

    Hi Anvar you can use the following circuit with 24-0-24volt transformer.
    http://www.circuitstoday.com/40v-dual-power-supply

  • anwar sadath says:

    sir,
    i’m an electronic student.
    can you send me the circuit of 35/-35,5A dc dual power supply for 100w subwoofer amplifier?

  • Dhilip says:

    Pls send me the circuit for 2.1 home theatre for computer

  • P.Srinivasan says:

    Dear sir, please send me this circuit pcb layout and other details , its possible to get this amplifier kit , please inform me my mail id srini_vasan1981@hotmail.com

  • Ajupi says:

    can i have the PCB shceme of this circuit ! my mail

  • Kuttymani says:

    Hi sir
    I am a electronics student. How to assemble the (2000watts) 5.1 hometheater. Send to the subwoofer board name, transformer ( volts & amps), volume knob value, and etc… Assemble procedure mention tamil. Please send me…
    My e mail id : Pmanidece90@gmail.com

  • Kuttymani says:

    Hi sir
    I am a electronics student. How to assemble the (2000watts) 5.1 hometheater. Send to the subwoofer board name, transformer ( volts & amps), volume knob value, and etc… Assemble procedure mention tamil. Please send me…

  • shakil says:

    sir plz send me pcb

  • seetharaman says:

    Hi Sairam you can use 4 or 8 ohms with 4 ohms the wattage will be 150 and with 8 ohms 75watts.
    Hi Shashidhar C1 is ceramic or polyester. C2, 3 &, 4 are electrolytic and C5 is ceramic tubular or disc. all capacitors are rated for a minimum of 50 volts.

  • sai ram says:

    sir how many ohm should the subwoffer speaker should be used in this circuit

  • shashidhar says:

    sir last time i asked u the same question i didnt get the answer so please mail me the answer sir please my id is s.shashidhar54@gmail.com

  • shashidhar says:

    sir i have a doubt which capacitor to be used in this circuit whether ceramic titanium or electrolytic capacitor how can we know which to use in the circuits

  • prasad says:

    hey shraventh, i have built it and works wonderfully, for more info check all the comment posted from the begining and built it exacly how it says

  • shravanth says:

    hello is this circuit is working

  • shakil says:

    sir send me pcb

  • shakil says:

    sir,plz send me pcb

  • prasad says:

    can i have the PCB shceme of this circuit ! my mail sevinfurly@gmail.com

  • shakil says:

    hello,sir plz send me 100w subwoofer pcb design.mial my adress shakil1432000@yahoo.com

  • shakil says:

    hello,sir plz send me 100w subwoofer pcb design.

  • Seetharaman says:

    Hi Kaifpkm you use with the systems sub woofer output. if you do not have any sub woofer output from your system use a sub woofer filter project appeared earlier.
    Hi Arc use 1/4 watt for resistors, which has no wattage indication. For Q3,4 & 6 use a versawatt cooling clips. For Q5 & 7 use an extruded alloy heat sink not less than 12sq inch. Cooling fans are not required. If you use a torroidal core transformer even transformer will not get heated up.

  • kaifpkm says:

    sir… is nessocery any filter board at input section

  • arc_reactor says:

    helo sir, all resistors should be from 1/2 to 1 watt? transformer be on a heat sink or any kind of cooling system like DC fan? sir pls help.;’ tnx in advance’.;’

  • M.M Yogesh says:

    actually there is a doubt to every body that what ratings sholud the power supply be…. (it is supposed to be 25-0-25 volt ac sec. supply…. and (mic6A14 diodes)…. and (4700uf/63 volt capacitors) should be used….. the output connected to a 100watts speaker sounds perfect….(MAKE SURE THAT Q4 TO Q7 SHOULD BE PLACED ON A MULTI FIN HEATSINK WITH HEAVY WEIGHT…… I WILL ALSO TRY TO PUT ON A SPEAKER PROTECTION CIRCUIT IN NEXT UPDATES….. THANKING YOU..:)

  • krishna kumar says:

    leelak1160@gmail.com is my mail id

    Regards
    Krishnakumar

  • Seetharaman says:

    hi krishnakumar send your email id

  • krishna kumar says:

    i want pcb design of this 100 watt subwoofer amplifier

  • seetharaman says:

    Hi Uday you can use a standard 24-0-24 volt 3amp capacity transformer with 5amps brodge rectifier and 4700uF 50 volt electrolytic capacitor and one number 0.1uF 63volt disc capacitor for positive and negative supply. (please refer to 150watts amplifier circuit for the power supply details)

  • uday says:

    getting 35v d.c is the problem i am facing can you help me pls sir.and i did audio amplifier using this sight and its perfectly alright and working thank you

  • seetharaman says:

    Hi Amar In place of 0.33 ohms (if not available you can use 3nos 1 ohm 2 watts in parallel) you can use 0.47ohms 5watts. In place of 560pF you can use any value from 100 to 470pF.

  • Amar saigal says:

    can i use any other resister instead of R14(.33 ohm 5w)
    can i use any other capacitor instead of c5(560pf)

  • arc_reactor says:

    sujeesh, try using a 100 watt speaker. check your power supply first; polarity of the rectifier diodes and the capacitor, replace R7 and check the components one by one. as stated above, all electrolytic capacitors should be at 100v. make sure that nothing is shorted. test it again first with a multi tester to see if you have an output then connect the speaker.

  • sujeesh says:

    hello sir,i didn’t got any reply for above comment

  • sujeesh says:

    i am waiting for your replay!

  • sujeesh says:

    Sir, i made this circuit when i tested this circuit with 8w,4 ohm speaker the resistor R7 starts burning.i made power supply with 27,0,27 transformer, 4,6A Power diodes and capacitor rates 4700 uf/63v. can you identifi what is the problem? Can you help me please?

  • seetharaman says:

    Hi Sjees DC output from a full wave rectifier with filter capacitor will be V RMS of the secondary of the transformer multiplied with root2 (1.414 times). current rating will not change.
    Hi Kanmaa you can use 9amp transformer. your current requirement is only 2 to 3amps. if you use 9amps ensure that you provide fast acting fuse of 4amps for positive and negative rain. in the event of short circuiting speaker leads will not blow the output transistors as they are like to dissipate 400watts which is beyond their apability.

  • KANMAA says:

    I WANT TO KNOW ,IS THERE IS ANY PROBLEM IF WE INCREASE THE TRANSFORMER RATING FROM 5A TO 9A,IS THAT OK?,WILL THE AMPLIFIER WORKS SMOOTHLY?

  • sujeesh says:

    Thank you for your last comment sir,
    i want to know that what is the ratio or any eqation to find what is the rate of voltage increase for rectifiation and filtration,after these process,what about current? Decrease or increase?

  • seetharaman says:

    Hi Sujeesh you require a DC voltage of +35 – 0 -35 volts at 5amps. Since the capacitors will be charged peak voltage, 1.4.4 times the RMS secondary voltage of the transformer. Hence you have to use 35 / 1.414 volt RMS transformer. That is 25-0-25 RMS secondary transformer rated for 5Amps. 27-0-27 will produce +38 -0- -38 volt DC. Can be used. Your peak power will be little higher, around 150 watts into 4 ohms load. but getting a 25-0-25 transformer is easy because it is a standard voltage 27-0-27 you made to order.

  • sujeesh says:

    Hai,
    i made this circuit and i want to make a power supply,i heard that when rectified voltage will increase. If so which transformer i want to choose? 35,0,35 5A,or 27,0,27 5A. Which is more efficient?
    Can you help me?

  • Sujeesh says:

    Hai,
    i made this circuit, and i want a transformer.i heard that when rectified, voltage will increase. If so 35,0,35 5A or 27,0,27 5A transformer i want to choose,which is more efficient? Can you help me?

  • seetharaman says:

    Hi Sinoj SWG is standard wire gauge. this represent the charector of the wire it dia current carrying capacity etc. (please refer to SWG Tables. A coin wound on a bare plastic former or without anr core material.

  • Shinoj says:

    Hi,
    what is mean by 16 turns and 22SWG air core coils in the transmitter circuit. What is SWG

  • seetharaman says:

    Hi Sairam Without polarity and values up to 0.47uF you can use ceramic. from 0.1uF to 2u2 you can use polyester paper etc capacitors. 4.7uF and above use electrolytic capacitors, they are polarized hence take care of polarity while connecting. Here C5 has to be ceramic, C1 can be ceramic or polyester. others are electrolytic capacitors. For high frequency, coupling and decoupling use ceramic.

  • sai ram says:

    sir i was asking about 100watts subwoofer please tell me wat capacitors should be used for c1,c2,c3,c4,c5 how can we find in circuit tat we have to use ceramic or electrolytic capacitor

  • sai ram says:

    sir please tell me wat capacitors should be used for c1,c2,c3,c4,c5 how can we find in circuit tat we have to use ceramic or electrolytic capacitor sir please email me this information please please please please

  • omer says:

    sir one more question i wanted to ask u …..
    is there any way to utilize telephone line’s voltage to operate a DSL modem????

    can we obtain 9 volts from our telephone line?

  • omer says:

    ahaan thanks sir :)

  • seetharaman says:

    Hi Omer if you are taking up audio as your project you can use motional feedback amplifier project which will be new for the present eneration. go through the project details and if you have any doubt please donot hesitate to contact me,

  • omer says:

    hi sir seetharman…….
    now i m in final year of BSC
    ((electrical engineering ))……..
    wilL u plz help me in deciding the final project ??
    please & if the project is related to sound systems in addition with other features n functions????
    plz give me some idea?

    i want a standard project …….. :)
    i hope u’lL help me as ever
    i’lL wait for ur reply , thankss :)

  • inzaniachi says:

    thanks so much for the circuit. it has helped me so much but
    please i have an 8pin 741 ic show me how i can connect it instead of using transistors

  • krishna kumar says:

    i want pcb design

  • Ramdas says:

    I need KIT for this particular circuit…pls reply me the details…

  • INDER says:

    SEETHARAMAN sir i send u email tht i want to buy this ready made circuit payment will be m\de to u please let me knw thanks

  • seetharaman says:

    Hi Omer the following circuit by ESP is very popular one. you may try it.
    http://sound.westhost.com/project89.htm

  • omer says:

    ok thanks :)
    and if u know a proper circuit diagram then do let me know ..

    thanks a lot sir :)

  • seetharaman says:

    Hi Omer SMPs for car amps are available with different voltages and current ratings. you can use them.

  • omer says:

    hi sir seetharaman , i have a question to ask……..
    if i want to install an amplifier with voltage rating 18-0-18 in my car then how can i able to convert 12 volts of car battery in 18-0-18 ??

  • seetharaman says:

    Hi Shubham Mosfets are best suited for high power amplifiers. IRF540 & IRF9540 are the best, freely available and inexpensive. The bias requirement per mosfet is 1.5 to 2.5 volt depends on the sample. For setting the standing current for both the output transistors you develop voltage between 2 to 6 volts between both the gates. adjust till you get a standing current of around 60 to 100mA through Mosfets.

  • Shubham says:

    Thanks sir,
    sir please tell me, is it better to use mosfet or fet in the place of transistor in main amplifier, as mosfet can handle large current, and they dont require heat sink. They also dont have thermal runway as transistor do, when they are heated up.

    If yes then which mosfet shuld be used ,with what biasing resistance.

  • seetharaman says:

    Hi Shbham Use a 100k log potentio-meter(three tags), preferred but if not available use 100k lin (not rheostat- 2 tags only). connect center of the potentiometer to C1. one end of the potentiometer to common(ground). Connect input between both the end of the potentiometer such that input signal ref is connected to common and actual signal is connected to other end of the potentiometer.

  • Shubham says:

    Sir, can you tell where i can place volume, treble and bass controle in circuit.
    Tell me the components between which i have to use control. Plz dont tell me in the language of low pass filter and amplifier. And for these controles, may i use rheostat.
    Sir, can u tell me which transistors form filter and which amplifier.
    Very very thanks

  • omer says:

    hi friends ….. does any one of u know about IC tda2052 ???
    if no then click this link to know about its efficiency and great and very easy design to built…….
    here’s the circuit of 3-way multisystem including 1 woofer and 2 speaker outputs……. can b used as a home theatre system too.. plz check out and ask me if u’ve questions about it…
    thanks :)
    http://adf.ly/265514/circuits-master

  • omer says:

    hi victor i’ve mailed you… please check it n tell me wat do u want to ask about this circuit , or any sort ov guideline…

  • victor says:

    ANY 1 IN NORTH INDIA NEAR DELHI MADE THIS CIRCUIT LET ME KNOW THANKS CONTACT ME IN EMAIL

    inder21norway@live.com

  • victor says:

    hi Omar i was waiting for ur reply man
    i am send u y new email

    inder21norway@live.com thanks

  • seetharaman says:

    Hi Shubham place the volume control between the input of the amplifier and the low pass sub woofer filter. use the low pass sub woofer filter appeared earlier, which gives you the full details for your doubts.
    http://www.circuitstoday.com/low-pass-filter-for-subwoofer

  • Shubham says:

    Sir where i can place volume controle in circuit, how can i give stereo input to single subwoofer as it is present in subwoofers which are commercial, as of intex etc.
    Thanks

  • seetharaman says:

    Hi Rahul it should give at least some highly distorted sound of low volume with 12-0-12 volt DC. The recommended voltage is 35-0-35 you require at least +25- 0 – -25 for this circuit to function. 2N5296 is OK.

  • rahul says:

    hi seehtharaman sir
    My sub woofer circuit is still not working. I have made the corrections . my transistors are fine .I have tested them as well.The circuit is not responding at all.Is it because of Q4? I have used 2N 5296 instead of 2N 5294. I have tested it with a 12 0 12 2A supply.

  • omer says:

    ok seetharaman sir……..
    thanks a lot….

    m gonna build this cct soon :)

  • seetharaman says:

    Hi Omer Connect it to ground(0 volt reference)

  • omer says:

    ahaan….. thanks for the reply sir seetharaman…..
    i’ve read from the data sheet that i should connect these pins either to the GND or to -Vcc ……. so should i do the connection in this way ?? the IC wilL operate normalLy????

  • omer says:

    ahaan….. thanks for the reply sir seetharaman…..
    i’ve read from the data sheet that i should connect theses pins either to the GND or to -Vcc ……. so should i do the sonnection in this way ?? the IC wilL operate normalLy????

  • seetharaman says:

    Hi Omer Mute is a function to just remove the input but output transistors will be consuming quiescent current, in this case it will be around 65mA but in standby mode the IC will consume only 3mA.in this case both are operated together hence no problem. refer datasheet.

    http://www.datasheetcatalog.org/datasheet2/a/0scgel8exqr094jlw9qfjx9qjc3y.pdf

  • omer says:

    n sir seetharaman i m wilLing to design this circuit…. please suggest me how to deal with the stand by & mute function……. how to deal mean tha how can i able to do the connections.. ??
    this is the circuit diagram…….

    http://electroschematics.com/wp-content/uploads/2009/02/tda7294-bridge.jpg

    thanks, i’lL wait for ur kind reply sir …

  • omer says:

    hi seetharaman , how u doin………. i have one question for u.. now a days i’m working with IC TDA7294 …….

    i have;nt done the connections ryt now….. but i cant understand how to deal with its standby & mute pins?????

    please can u suggest me how to deal with these pins of this IC???????

  • rahul says:

    thanks a lot seetharaman sir for your mail.I have got my answer.

  • rahul says:

    Hi seetharaman sir
    hope you remember me I have made the circuit but is not working. You told me to go to electronics hardware man .I went to him.yes you were right .Two of the transistors were connected in wrong way. i have again connected them in a proper way but still it is not working.Sir I have asked you is there a way to check the E,B &c configuration of the transistors using digital multimeter?Can you please help me with this circuit.I have even mailed you about this but could’t get your answer.

  • omer says:

    ok thank seetharaman …. i’lL try….. :)

  • seetharaman says:

    Hi Omer for both the amplifiers you feed from the same power supply. plus, minus and common.

  • omer says:

    ok Mr. SEETHRAMAN ……. but how will i do the connections of single supply with two amplifiers ???

    i mean should i connect in parallel or in series ??????? etc ?? with the amplifier ??

    & wat about the ground terminal ?????

  • rahul says:

    sir
    I went to an electronics hardware man, yes u were right. I made a mistake in connecting the E & B of the main transistors. Sir is there a way to know the EBC configuration of transistors using digital multimeter .Small transistors can be tested using that hole in the side but sir what about big transistors ??

  • seetharaman says:

    Ho Omer you can use two amplifier with one supply, it should be rated for double the current of one amplifier. good quality filter capacitors are required. you can use double the value shown.

  • omer says:

    dO u need a pcb layout?

  • WANGU says:

    please send me the circuit diagram and the components pliiiiiiiz

  • victor says:

    yes omar i need lay out and component list please thanks
    my email is vicktorcyprus@yahoo.com

  • omer says:

    hi mr. SEETHRAMAN…… i have a question that can i use two channels on a single power supply??????????

  • omer says:

    VICTOR ,,,, yes you can ask me about this circuit….. i’ve built this

  • victor says:

    can any one help me out with complete layout and components for this circuit coming to India soon wants to build for my house as gift for father

  • victor says:

    HIYA MIKE PRESS MENU OR BLUE BUTTON ON THE PLAYER AND PRESS POWER BUTTON TOGATHER IT WILL REFRESH TO FACTORY SETTINGS IF NOT THERE MUST OVER LOAD OR SHORT CIRCUIT IN SPEAKER CHECK THAT

  • JAKUV says:

    HI..
    I WANT A LAYOUT PCB FOR THIS CICRCUIT INCLUDING A POWER SUPPLY..
    EMAIL AT tinytech99@yahoo.com
    PLEASE HELP ME FOR MY FINAL PROJECT..

  • MIKE says:

    Hi there, can you help me with my problem,……my AIWA NSX-K880 component is always in standby mode, it only displays a red light…
    when I press the power button nothing will happen….

    any related suggestions or any procedures to solve will do…

  • seetharaman says:

    Hi Chanaka 28-0-28 @ 3amps will give you 40-0-40DC with 10000uF as filter capacitor for both positive and negative supply. which will give you > 90watts RMS into 6 ohms speaker.

  • chanaka says:

    Hi MR. Seetharaman,
    can i use 28-0-28 3A center tap transformer for my 6ohms 100W
    sub woofer speaker? because i don’t have 35-0-35 5A transformer, and i used BD140 and BD139,instead of 2N6107 and 2N5294. but 2N3773 is same. pleas tel me these are suitable foe this amplifier. I’m from srilanka

  • Seetharaman says:

    Hi Anish you can design, ensure current carrying tracks are wide enough to handle the current. ensure current carrying tracks are away from small signal tracks.
    Any chemist will be in a position to supply Ferric chloride.
    Add dilute hydro-chloric acid to give burr free edge finish. you can warm the solution little to improve speed of etching.
    Copper clad sheet available with base material phenolic, hylam or glass epoxy.
    Etched board is called printer wiring board.[should not be called as printed circuit board, as there is no circuit in it, it is just a board used for inter connecting (wiring)components, hence the name printed wiring board]

  • Anish says:

    Hi MR. Seetharaman,
    I dono where ask this question, my apologies if its wrong to ask here. will you answer a few questions?
    1. can i design the pcb design for this circuit using expresspcb?
    2. To etch our own pcb, where to get ferric chloride? I mean, will it be available in local shops, or it must be got in cities such as chennai?
    3. what is the name of the copper plated board used to print and etch the pcb?

    Thanks.

  • Seetharaman says:

    Hi Subbu I am on it and inform you soon.

  • Seetharaman says:

    Hi Victor Your box (45liters) can be of internal dimensions 50cm(W) X 36cm(H) X 25cm(D) sealed air tight enclosure with centrally, front mounted speaker. box can be of 20 or 25mm ply. joints should be sealed with white Fevicol, to make the enclosure air tight.
    Hi Manjula around 50 liters internal volume 8 to 12″ woofer of 8 ohms impedance and power handling capacity of 100Watts RMS power.

  • manjula says:

    dear sir ,
    what should be the cabninet size for this
    woofer size & ohms
    Dimention of the box?
    please reply
    thanks

  • victor says:

    Mr Seetharaman

    Namaskar Sir mere pass Blaupankt ka Subwoofer hai 10 Inches
    for this perticular circuit muje Box Design chahiye ghar ke liye
    please help kar sakte hain ??

  • subbu567 says:

    Hi Seetha Raman-Have mailed you at Hotmail id-Kindly respond when convenient.Thanks

  • edgardo rante says:

    i need complete disign of 100watt sub woofer amplifier with placement guide and part list.plz give me the link of full disign and diagram. thanks a lot

  • OMER says:

    hi frndxxx plz like this facebook page to get knowledge about latest amplifier circuits………

    http://www.facebook.com/pages/Amplifier-circuits/220999274586009

  • Seetharaman says:

    Yes can be used

  • Hengilbert says:

    2SC5200 can be used in these circuit too..

  • habibur says:

    A great job keep it up

  • habibur says:

    thanks

  • Seetharaman says:

    Hi Kumar with 5amp supply your transients will be quite good.

  • kumar says:

    kindly reply me.

  • kumar says:

    hi seetha. i put my home built 2ohm 12inch sub woofer with an adding lowpass filter.&sound is good as i thoght.but i use 3A tf.i cannot increase volume i think the problem is 3A tf.whats ur options?

  • Seetharaman says:

    Hi Omer you can use BUV20. a very good high current switching transistor will suit our application.
    Hi Kumar kindly try motional feedback amplifier simple and good transient and deep bass. you must listen to believe.
    http://www.circuitstoday.com/motional-feed-back-amplifier

  • OMER says:

    hi, i wanna ask u that can i use BUV20 in place of 2n3773 transistors????????

    my provider gave me these…….

  • kumar says:

    well done seetha im from srilanka.happy abt ur 100w ckt.keep it up!

  • omer says:

    hi sir seetharaman…….. i wanna know from u dat , can i use MJ15004 or any other series of this transistor in place of output transistors … 2N3773 ????????????

  • Bhaskara says:

    Dear Mr Seetharaman,

    In my marantz SR 73 AV Receiver, in one of its front Channels( Front Left ) a “pat-Chit” noise begins after 2 or 3 minutes of switching on, some times bit earlier. Initially when switched on it works very fine( there is a relay inside, which switches on the speakers after a brief delay, this may be the reason there is no such sound immediately after switching on) but this noise starts after some time. But sound/music out-put is very clear but with this noise. The sound persists even when the in-put volume is fully reduced to zero. I am compelled to use this device as just pre-amplifier with all its pre-outs connecting to my another 5.1 amplifier. Pre-outs are good and is working well.

    I am unable to locate the problem. I for once I thought out-put coupling capacitors may be leaking( no such indication inside! the cabinet) and the capacitors try to charge up swiftly thereby producing this noise.

    Please advise what is the problem with my amplifier.
    And how can I fix it.
    Kindly mail me at bhaskara.india@gmail.com

    Regards.
    Bhaskara N

  • badboy says:

    seetheee my filter?????????//

  • Seetharaman says:

    Hi Khetran You have to use proper heat sinks for driver and output transistors.

  • KHETRAN says:

    And there wouldnt be any over heating problem right?

  • Seetharaman says:

    Hi Khetran you can try BD139,BD140 or MJE340,MJE350 instead of 2N6107 and 2N5294

  • KHETRAN says:

    Still waiting for your reply SEETHARAMAN.

  • omer says:

    okkkkk thanksssss ……. :)

  • Seetharaman says:

    Hi Omer MJ15003 will be the best substitute.

  • omer says:

    hi seetharaman!! yar i’m using 2N3055 but its giving me hum sound..can u suggest me another alternate :( ??

  • Khetran says:

    Hi,

    SEETHARAMAN

    I am implementing this circuit as part of my analog electronics project. Is there any replacement for 2N5294?

    And secondly reading above comments I am a bit confused now. Do I have to change any values in it? Some people are complaining that Q5, Q6 and Q7 along with some resistors are getting too hot. Do I have to change any component’s value or implement it as it is?

  • Seetharaman says:

    Hi Omer you can use

  • omer says:

    hi seethraman, can i use 2N3055 in place of 2N3773 ???

  • omer says:

    hi MISKO…. you can use 2N5303 as its alternate… i’m using this n working very well……….

  • omer says:

    hi MISKO…. you can use 2N5303 as its alternate… i’m using this n working very well……….. :)

  • omer says:

    hi MISKO…. you can use 2N5303 as its alternate… i’m using this n working very well……….. :) good luck to..

  • Seetharaman says:

    Hi Bad Boy I am just with correcting power amplifier problems. By Monday i will check the filter portion and give you feedback.
    Hi Sebin you can try this circuit the best one with delay line etc.
    http://circuitdiagram.net/surround-sound-decoder.html

  • Bad boy says:

    seethe did you complete that filter ckt?????????????????????????

  • Sebin jacob says:

    Hi seetharaman sir,
    Do u have any good stereo to 5.1 converting circuit with delay.if u have can u please sent me.

    sebinsony@gmail.com

  • MISKO says:

    hi seetharaman sir,
    can you tell me something about substitutes for 2N3773 because I cant find 2N3773 transistor.
    Thanks

  • Seetharaman says:

    Hi Sebin it is the circuit you can use, though not exactly 5.1 still it is a good stereo to 5.1 converter, will sound great. in some converters for the rear left and right a small delay circuit is also included to improve and get theater effect.

  • sebinjacob says:

    hi seetharamansir,

    please see the 3rd circuit in this page

    http://sound.westhost.com/project18.htm

    do u have any circuit to convert stereo input to 5.1 please sent me the link.

  • Seetharaman says:

    Hi Sebin this is what has been used in early days of surround sound development. Please go ahead you will enjoy with the new experience playing just good stereo music.

  • ishan1211 says:

    Hi friends may i have PCB diagram for this circuit, please upload it and pass me a link.

  • sebinjacob says:

    hi seetharaman sir,

    I am looking for a circuit to convert stereo out to 5.1 out.I have found a circuit please see the circuit and see weather it is correct,and tell me if i need to make any change in this circuit.Also please sent me if you have any alternate better circuit.

  • Seetharaman says:

    Hi Badboy I have gone through the circuit i have assembled only the power amplifier, the DC stability of out put stage is poor. i am just on the job will give a feed back soon.

  • masoodalvi says:

    sir ,i want a 150 watt amplifier using igbt transistor.thanking you.

  • Bad boy says:

    seethee did you notice that ckt i sent to your mail???????
    did you try it?????
    what is its diffect????????

  • Seetharaman says:

    2N5294 NPN BD139 and for 2N6197 BD PNP BD140 can be used.
    You can try using BD337 for NPN and BC327 for PNP.

  • Furhan says:

    Hi sir,
    The circuit is very good and easy. But some Problem in this circuit. The transistor (2N5294) is not available in market. Which is the transistor who match from it.
    Please told me which is the another match transistor.

  • Seetharaman says:

    Hi Burhan Mr Sebin is correct this capacitor is used for decoupling negative voltage to Q1 and Q2, hence it has to be reversed.
    Hi Sebin I recently tried TDA2050 push pull > 70 watts into 8 ohms load. The standing current is around 120mA after driving the amp for 1/2 hr with amplifier running quite warm and found that the standing current has returned back to 120mA. very stable with very low distortion. This IC is quite economical with very few external components.

  • SEBIN JACOB says:

    hi BURHAN,

    The polarity of the capacitor c2 given in the digram is wrong please connect the positive of the c2 to the negative of c3 and negative to the r3 and r4 (JUST OPPOSITE OF THE POLARITY MARKED IN THE CIRCUIT THIS WILL SOLVE YOUR PROBLEM)please see that you are using capacitor rated more than 50v.

  • SEBIN JACOB says:

    hi BURHAN,

    The polarity of the capacitor c2 given in the digram is wrong please connect the positive of the c2 to the negative of c3 and negative to the r3 and r4 (JUST OPPOSITE OF THE POLARITY MARKED IN THE CIRCUIT THIS WILL SOLVE YOUR PROBLEM)please see that you are using capacitor rated more than 50v

  • burhan says:

    hello seetharaman C2 (4.7uf 100v)is getting bold and then it is exploding after several minutes why it is happening like this DC offset voltage is getting negative voltage…..

  • SEBIN JACOB says:

    HI SEETHARAMAN SIR,
    I HAVE VISITED THE LINK YOU HAD GIVEN ME.SEE THE FOLLOWING LINK AND PLEASE TELL ME YOUR OPINION WHICH CIRCUIT I HAVE TO SELECT TO GET GOOD OUTPUT.

    http://electroschematics.blogspot.com/2011/04/20w-surround-audio-amplifier-with-si.html

  • Furhan says:

    hi sir!
    I need a good 100w amplifier with high output for sub-woofer circuit diagram.
    If you have the circuit please send me my E-mail furhan_69@yahoo.com.
    Thanks.

  • SEBIN JACOB says:

    HI SEETHARAMAN SIR,

    I NEED A GOOD 12V AMPLIFIER WITH GOOD OUTPUT FOR 8OHMS SUBWOOFER IN MY CAR IF YOU HAVE THE CIRCUIT PLEASE SENT ME AT sebinsony@gmail.com OR PLEASE GIVE ME THE LINK

  • joey says:

    i like this site. i’m an electronics graduate..

  • Seetharaman says:

    Hi Hemant it will be distorted low volume.
    seethasub@hotmail.com

  • Bad Boy says:

    seethe plzzz send your e mail id.i sent you low pass fiter ckt i usinggg

  • omer says:

    thanks a lot man ……. i will replace it tommorrow ;)

  • hi,sir,
    what happen when we use +12/-12 in the replace of +35v/-35v…

  • Seetharaman says:

    Hi Omer the transistor which is cool is defective it has got shorted the other one is OK. You replace the cool one. Since this circuit functioned for some time indicates the amp is ok. you require a better heat sink.

  • omer says:

    hi seetharaman sir , i designed this circuit it worked very well but after some time i got fluctuating sound with hum…. and the output transistors were drastically hot… and now when ever i turn it on it gives hum sound and a lil bit input signal and my 1oo ohm 2watt resistor connecting to -35v also burned out many times… what is the problem :( and one thing more one of the output trasistor get so much hot whule the other is not so… where is the problem ?? is there any problem in output transistors? or any thing else going wrong?
    please please please please help me out… i love this circuit running accurate :(

    i will be very very very thankful to you….

  • Seetharaman says:

    Hi Sebin use an operational amplifier feed one signal to inverting input and the other signal to non inverting input. you get the difference between the signal (say L – R) now feed this this signal to an inverting unity gain amplifier you will get the other signal (R – L).

  • Sebin jacob says:

    Hi seetharaman sir,
    how we minus left signal from right and right from left

  • Seetharaman says:

    Hi Sebin L – R is Left channel Signal minus Right channel signal and R – L is Right minus Left signal. these two signals will become rear left and right signals.

  • sebin jacob says:

    hi seetharaman sir

    sir i didnt understand about the L-R (left right)rear and right-left rear how we get this input from sterio input can u please explane this.

  • sebin jacob says:

    hi seetharaman sir

    sir i didnt understand about the L-R (left right)rear and right-left rear how we get this input from sterio input can u please explane this.

  • Seetharaman says:

    Normally Ahuja has taken care of it. has it developed recently or it is there from the beginning. you can use a timer relay through which you can connect output of the amplifier to a dummy load (resistance of suitable value and wattage) during switch on and after about 10 to 20 seconds you can change to speaker. if the problem has developed recently kindly contact Ahuja for tips.

  • JOBY says:

    I have an ahuja 500watt amplifier when i switch on a big sound “pat” is coming out of speaker how can i prevent this sound

  • Seetharaman says:

    Hi Sebin use a sub woofer filter for L + R signal feed it to Sub woofer amplifier keep that in front of you Left and Right signals can be used as front speaker signals.Now use L-R (Left – Right) signal for rear left speaker and R-L signal for Left Left Channel. This will give you a good surround effect with a good stereo signal. With mono signal all signals will shift to front center and rear speakers will become quite. (with mono signal L=R hence L-R will become Zero. Try and enjoy it. you will definitely like it.
    Hi Badboy if you are using the subwoofer appeared in Circuits today it should work perfectly. still if you have problem add 100 PF ceramic between inv and non-inv input of the first stage amplifier IC.

  • badboy says:

    seethe i make a sub filter with tl074.but when potentio meter full audio signal get cut and a hissig n burr sound genarate what to do?????? i,m going to quit

  • sebinjacob says:

    HI SEETHARAMAN SIR;

    HOW CAN WE CONVERT STERIO AUDIO OUT TO 5.1 OUT. DO YOU HAVE ANY CIRCUIT.

  • pj says:

    Hi Seetharaman.. sir can you add me on my yahoo mail.. i really need your help .. thanks.. sankapa04@yahoo.com

  • aris says:

    hello sebinsony, its wrong, please read mr. seetheraman reply dated september 19, 2010.

  • SEBINSONY says:

    Hi Seetharaman sir,
    Sir please see the polarity of the capasitor c2 in the given circuit is it correct?

  • Seetharaman says:

    Hi Jacob C5 is ceramic capacitor hence no polarity.

    February 21, 2011 at 12:21 am
    HI Lordsville I can suggest a very simple cross over which is just sufficient. Woofer through 300turns of 18SWG enameled copper wire (1mm dia wire will do)on 25mm dia plastic former wound for 40mm length. Mid range through 25uF non polar capacitor or 2nos 50uF electrolytic connected back to back and tweeter through 2.5uF non polar (here you can use a polyester or paper or 48″ ceiling fan run capacitor)or 2nos 5uF (4.7uF standard value) electrolytic capacitors connected back to back. I am using in my system an 8″ Philips 40Watts woofer, 6″ X 4″ Philips standard speaker as midrange and Philips 1″ Dome tweeter.

  • Sebin jacob says:

    Hi Seetharaman sir,
    Sir please see the polarity of the capasitor c5 in the given circuit is it correct? sir my amplifier is now working fine.thank u so much 4 ur guidance through out my construction.sir i would like 2 make a cross over network for my speaker box which has a tweeter, speaker and a woofer can u please help me

  • aris says:

    sir, thank you.

    • Sir, please, i need a simple but durable inverter (circuit diagram) that works on 6volts DC supply to give an output AC Of about 220volts to 230volts, with an output power of about 500watts. Please sir, I’m just a beginer in electronics that wants to be the best he can be in electronic projects. I had ever had this unerasable interest in electronics since my tender age, and i believe i can help improve the society electronically with your promising guidance and support. Thanks so much. I wish more greeze to your elbow.

  • Seetharaman says:

    Hi Aris without test instruments it will be difficult. But practically you can find out by reducing the volume level to just audible level, when you are just close to the speaker. a choking type of sound indicates crossover distortion. at higher volume it will become almost normal sound.

  • aris says:

    dear seetheraman,
    how do i know sir if the amplifier is having a crossover distortion?

  • SEBINSONY says:

    hi seetharaman sir,

    With multimeter is it possible for me to check the standing current.How can i check it where i have to connect the red probe and black probe to find the standing current,which resistor value i have to change in order to adjust the standing current.With out input my amplifier output transistors are cool when i play songs for a long time (1 to 2 hours) transistor is getting heated up i think Q5 is getting hotter. Q7 is only producing normal temperature the heat from Q5 makes Q7 heated up.Kindly help me sir.

  • Seetharaman says:

    Hi Sebinsony You may short the resistance R9 and 10 if the output transistors are cool it indicated your standing current is high. Check it should not be greater than 25 to 30mA. If it is too less then distortion will set in at low volume levels (crossover distortion)then add 10 ohms and try if it within limits leave it. if it is still less increase the value if it is high reduce the value and finalise now the heating should be ok.
    Hi Aris congratulations. with indicated transistors some consume little high current, with equivalent transistors you have to do little experimenting with R9 and 10

  • aris says:

    i have completed this project and its working without any problem at all. my advice is to just follow the diagram and its components and there should not be any problem. this circuit works well.

  • SEBINSONY says:

    hi seetharaman sir,

    my amplifiers output transistors 2n3773 is getting very much hot when it works for a long time i am connected it to a big heat sink and also a cooling fan is their still it is getting heated and also the metal case also getting hot due to the heat from the transistors.As u said if i put a link between r9 and r10 will it stops terribly heating or should i need to increase the value of any resistors. r12 is also getting little heated.every thing else is fine.kindly please help me sir..

  • SEBINSONY says:

    hi seetharamansir,

    The q7 of my amplifier was shorted now the problem is solved.but r11 r12 r13 is getting little heated is it a problem.But when i play maximum volume the transistors q5 and q7 is getting heated so-much.what is standing current.

  • Seetharaman says:

    Hi Jacob 2.2uF is 225K (2,200,000PF) 224 is 0.22uF 2.2uF any capacitor you can use non polar is preferable, if not available 2.2uF 63volt electrolytic you can use (take care of polarity). Voice will get through, that depends on the attenuation in the filter if the curve 40dB / octave you will get low volume of voice is it is 20dB it will be more etc. Fix a link between Q4 and Q6 base (shorting bias components D1 D2 R9 & R10)energise, if heating comes down you have to short R9 and 10 and try if things are ok try playing music(we are trying to reduce standing current). If they are still getting heated up, Q3 Collector emitter may be short.

  • sebin jacob says:

    hello seetharaman sir

    today when i connected my amplifier the r12,r11,r13 is getting heated.
    r11 is getting very much heated and once it burned out also the transistors 2n3773.again i replaced it and when i give input all the transistors mentioned above are getting heated r11 is getting terribly heated.what happened to my amplifier i also replaced q6 also connections are all ok

  • SEBIN JACOB says:

    hello seetharamansir,

    The vocal sound is not of the local radio it is of the input which i have given the vocal voice of the song which i played is heard in a very low through the sub woofer.can i connect a 2.2uf poly carbonate capacitor at the input of the filter in serious will it rectifies the problem,can you please suggest me a method.When i asked for 2.2uf polycarbonate capacitor the shop keeper gave me a polistor capacitor written on that 224k 400v Is that same as the one you suggest for the c1?

  • Seetharaman says:

    Hi Jacob local radio is getting in, through connecting cables acting as antenna. all inputs should be protected with RF filter. may be 100PF capacitor can be used as RF bypassing capacitor.

  • SEBINJACOB says:

    i have connected the filter and connected to my sub woofer.the problem is some vocal sounds are also heard through the sub woofer is there any solution to rectify this.

  • SEBINJACOB says:

    HELLO seetharaman sir,

    MY AMPLIFIER 1.5k 2W RESISTORS IS SLIGHTLY GETTING HEATED IS IT A PROBLEM.SHOULD I NEED TO INCREASE THE WATTAGE (TO 5 WATT.
    i am also using a stereo amplifier with 2n3055 wit 12v duel power supply,is it possible to use the simple low pass filter (1k resistor with 470 pf capacitor)for this at the input,i have the doubt because this has a stereo input.

    ANY WAYS WITH YOUR HELP I COMPLETED MY AMPLIFIER AND IT IS WORKING GOOD THANK YOU SO MUCH SIR……….

  • Seetharaman says:

    C2 is decoupling for R4 negative supply. use minimum 50volts capacitor. 2.2nf (2200PF) is red red red. 2.2uF will be written on the capacitor. 2.2uF is 2,200,000PF RED RED Green i don’t think you will get that color code.

  • SEBINJACOB says:

    seetharaman sir,
    i am using a stereo amplifier with 2n3055 wit 12v duel power supply.is it possible to use the simple low pass filter (1k resistor with 470 pf capacitor)for this at the input,i have doubt because this has a stereo input.please see my previous post also and kindly replay me for all the doubts i have asked.because i am professionaly a business management student but i am very much interested in electronics from my childhood.

  • SEBIN JACOB says:

    HI SEETHARAMANSIR,

    I COMPLETED MY AMPLIFIER AND JUST MADE IT WORK US AN AMPLIFIER (WITH OUT SUB FILTER)THE SOUND WAS EXCELLENT AND I LIKED IT VERY MUCH.I AM PLANING TO BUY A SUB-WOOFER FILTER WHICH COST ONLY 65 TO 75 RS.SIR WHAT IS THE COLOR CODE OF 2.2UF NON- ELECTROLYTIC CAPACITOR IS IT RED-RED-RED.I GAVE INPUT FROM MY MOBILE AND WHEN I PLAYED THE SONG NO HUMMING SOUND WAS THERE BUT WHEN I MUTE THE MOBILE SMALL HUMMING SOUND IS THERE ALSO I FIND THE CAPACITOR C2 (4.7UF 250V)GOT BULGED AT THE TOP,WHAT IS THE PURPOSE OF THIS CAPACITOR
    .THE HIGH VALUE RESISTORS ARE ALSO GETTING LITTLE HEATED WHEN I GAVE MAXIMUM INPUT AND WORKED FOR HALF AN HOUR,IS IT A PROBLEM.

  • Seetharaman says:

    Hi Jacob you are correct. please go ahead constructing all the best.

  • SEBIN JACOB says:

    HI SEETHARAMAN SIR
    we have to connect this low-pass filter (1k resistor &470pf capacitor) at the input signal right.I mean before the c1 capacitor.

  • Seetharaman says:

    Hi Jacob this is to avoid stray pickup of HF and resulting in hf instability. If amplifier, filter net work, power if all are in one metal chassis then not required. if not it is better to provide it as general precautions to all power amplifier to avoid the amplifier getting over driven by high frequency from previous stage or through stray pickup, which will lead to severe distortion or instability.

  • SEBIN JACOB says:

    HI SEETHARAMAN SIR

    AS YOU SAID IF I ADD A 1K RESISTOR IN SERIES TO THE INPUT AND A 470 PF CAPACITOR IN PARALLEL WILL MY AMPLIFIER GIVES MORE BASS, AS I AM USING IT AS A SUB WOOFER AMPLIFIER.IF I AM USING A SUB-WOOFER FILTER IS IT NECESSARY TO USE 1K RESISTOR AND 470PF CAPACITOR, WILL IT MAKE ANY IMPROVEMENT IN THE EFFECT.WHERE I HAVE TO CONNECT THIS SIMPLE LOW PASS FILTER BEFORE THE SUB WOOFER FILTER OR AFTER THE SUB WOOFER FILTER.

    SIR U R HELPING ME A LOT.THANK YOU SO MUCH SIR.SIR WHICH PLACE ARE YOU FROM.I AM FROM INDIA

  • Seetharaman says:

    Hi David for a class room you have to concentrate on voice frequencies rather than low frequency. a full range speaker (Hi-Q) will be ideal. say 6″ X 4″ or 6″ will be ideal in a small air tight enclosure of say 4 to 8 litres internal air volume. you can use TDA2040 amp with a passive tone control appeared in our circuitstoday earlier.

  • Seetharaman says:

    Hi Jacob you have to increase the capacitor to 2.2uF for sub woofer application

  • SEBIN JACOB says:

    HI SEETHARAMAN SIR,

    I HAVE COMPLETED FIXING THE COMPONENTS ON THE PCB.I AM GOING TO USE THIS AS A SUB WOOFER AMPLIFIER WITH A SUB WOOFER FILTER,SHOULD I NEED TO CHANGE ANY OF THE CAPACITOR VALUES TO GET MORE EFFECT.YOU HAVE SAID IN YOUR PREVIOUS POST DATED 4TH MAY TO Increase C1 to 2.2 or 4.7uf non electrolytic capacitor to improve low frequency response to 10Hz or so, with the present value the roll of will be above 50Hz itself.

  • David says:

    I’m a teacher, and I would like to use in class room. I have a wireless microphone. I need at least 20w, with the smaller woofer size. What woofer you recommend? Where do I insert volume and treble pots? Best Regards.

  • SEBIN JACOB says:

    Thanku seetharaman sir

  • Seetharaman says:

    Hi Bad boy the positioning of the speaker in your room can affect the sound inside the room. even the phase mismatch due to distance between your ear and different speakers ( sub woofer and satellite speakers) can also give raise to this problem. Try by relocating and by adjusting the angle of your speakers can definitely improve the response in side the room.
    Hi Jacob if you are very particular you can use 3nos 1 ohm 2watts resistance in parallel. but 0.47 5 watt is good enough and it will not affect the performance.

  • SEBIN JACOB says:

    hi seetharaman;
    i have got all the components in the circuit except .33ohms 5W resistor. Instead of that i got .47 5W is that enough,or is their any substitute for that kindly help me.

  • badboy says:

    seetaaraman i complete my sub.it have a awesome boom sound.can hear up to 150-200 meters from my home but it dosin’t have the jerking power inside my room????????? why mydear

  • Seetharaman says:

    Hi Jacob sorry for the delayed reply. You have to use insulating kits for the output transistors, while fitting them on to the heat sink.(mica or plastic washer with non metallic insulating bushes – washer and transistor surfaces to be smeared with silicon conductive grease to improve the thermal conduction). If you use + & – 35 volt DC for supply and 8 ohms speaker the output will be around 75watt RMS. with + – 40volts the output will be 100Watts RMS into 8 ohms speaker. With + – 22volt supply the output will be 100 watts into 4 ohms load. To avoid humming you have to use perfect layout. use large value filter capacitors with one more diode and filter capacitor after main filter capacitor as pi filter. connect power supply zero volt reference the chassis earth at only one point, that too at the amplifier input socket. use thick short length of wire say 2.5sq mm less than 3 inches to connect the power supply to the amplifier.

  • SEBIN JACOB says:

    Thank you omer
    Thank you so much
    once i complete this project i will tell you how it is for me ok bye.

  • omer says:

    hi sebin jacob , yes i have designed this circuit and its working very well…. humming sound is produced when u use capacitors of less value to remove this humming sound ( if produced) use capacitors of higher values with the supply… i:e 4700 Uf’s minimum…… i m using 6800 Uf capacitors…with 25-0-25 transformer… and 3ampere diodes bridge….
    if u want a design of power supply then plz visit this link …. n do comments plz… :)

    http://adf.ly/265514/circuits-master

  • SEBIN JACOB says:

    Hi seetharaman

    I am aware about the sub-woofer filter. Kindly please read the doubts i am writing below.

    My doubt is regarding the watts. It is said that we get 100 w output, is it for 4 ohms or for 8 homes woofer. should I need to make any changes in this circuit(is this circuit correct).For the transistor 2n3773 body is the collector, so when we connect both the transistors to a heat sink the collector of both transistors 2n3773 get short through heat sink is their any problem for that. Should I need to use bigger heat sink for all the transistors, or for the Q5 and Q7 big heat sink and for the rest small heat sinks? Some amplifiers produce humming sounds is this a good amplifier which is very quite when it is at the ideal state expecting your replay and helps.

    Hi omer;
    I hope you had completed and start using this circuit. How is it? Is it a good one? Does it produce any humming sound at the ideal state? Do you made any changes in this circuit to make it works? Help me please I am interested I this circuit I need to built this after considering your opinion I am waiting for your replay.

  • SEBIN JACOB says:

    Hi seetharaman

    I am aware about the sub-woofer filter. Kindly please read the doubts i am writing below.

    My doubt is regarding the watts. It is said that we get 100 w output, is it for 4 ohms or for 8 homes woofer. should I need to make any changes in this circuit(is this circuit correct).For the transistor 2n3773 body is the collector, so when we connect both the transistors to a heat sink the collector of both transistors 2n3773 get short through heat sink is their any problem for that. Should I need to use bigger heat sink for all the transistors, or for the Q5 and Q7 big heat sink and for the rest small heat sinks? Some amplifiers produce humming sounds is this a good amplifier which is very quite when it is at the ideal state expecting your replay and helps.

    Hi Umer;
    I hope you had completed and start using this circuit. How is it? Is it a good one? Does it produce any humming sound at the ideal state? Do you made any changes in this circuit to make it works? Help me please I am interested I this circuit I need to built this after considering your opinion I am waiting for your replay.

  • Seetharaman says:

    Hi Sebin Mr Omer is correct, you have to use a low pass filter before feeding the signal to the amplifier.

  • SEBIN JACOB says:

    hi omer

    my doubt is shoud i need to make any changes in the given circuit.Will this circuit works.My sub woofer is of 8 ohms 100w.Is some amplifiers produce humming sounds and some disterbance,what is ur opinion abt this circuit.

  • omer says:

    hi SEBIN JACOB , i have experienced TDA 2030′s and also this circuit… with respect to wattage this circuit is more strong… but if u want pure woofer output from this circuit then u should use a subwoofer low pass filter before this circuit….I hope it will fulfill ur requirement..

  • SEBIN JACOB says:

    I am using a simple sub woofer with ic tda2030X2 the out put is not satisfactory for me.Is this circuit good for home sub-woofers i want good bass (thumping sound) please help me.I will only start making it only after your replay.i am having a transformer of 25-0-25 will it gives +-35 when rectified,is that ok for the best working of this circuit.

  • SEBIN JACOB says:

    hi Mr.SEETHARAMAN,
    I have made the PCB for this circuit i have doubt regarding the watts. It is said that we get 100 w output,is it for 4 ohms or for 8 homes woofer.should i need to make any changes in this circuit.For the transistor 2n3773 body is the collector,so when we connect both the transistors to a heat sink the collector of both transistors 2n3773 get short through heat sink is their any problem for that.should i need to use bigger heat sink for all the transistors or for the Q5 and Q7 big heat sink and for the rest small heat sinks,i am expecting your replay at the earliest.any ways you are great in electronics and you have the helping mentality also.

  • aris says:

    im very grateful for the idea.tnx

  • Seetharaman says:

    Hi Aris for 10inch woofer say with soft textile rubber cone with free movement sealed 35 to 45 liter internal volume will be the best. If it is a tight rigid cone full range speaker, around 60 liter sealed enclosure with internal volume will be ideal. Make it front center mounting that will be the best. For 8″ woofer I am using 50 X 30 X 16 cm external with 20mm wood board carpet felt fitted on the internal surface of the enclosure. external measurement with 20mm ply board of 75 X 45 X 20 cm for 10″ and 12″. These sizes were based on Philips audio application book and suitably assembled by a carpenter for me by using Philips 8″ & Luxco 8″ woofer – bolton 10″ & Luxco 10″ and JLS 12″ full range.
    .

  • ARIS says:

    hello everybody, hi seetharaman
    i have finished this project already together with its filter. they are both working very well. by the way sir seetheraman, what is the ideal size of the speaker enclosure? im using a 10 inches speaker. tnx.

  • Seetharaman says:

    Hi KVS perfectly ok. only thing is you will get less wattage with +, – 24volt you will get around 32 watts into 8 ohms speaker and 64 watts into 4 ohms speaker. Put a link between Q4 and Q6 base the current drawn by output transistors should fall down, if other things are connected properly. If current is still high and 100 ohms are getting heated up check the transistor orientation

  • kvs says:

    hi seetharaman. thanks for your kind reply. but now i’m using 2x24v smps. one smps +v connected to other smps com. this connection is i’m taking as com. and taking other two end as +24v & -24v.

  • momok says:

    hi seetharaman,
    thank you for answering my question.
    :) ))

  • Seetharaman says:

    Hi KVS earth is nothing but 0 volt reference of +35 and -35 supply. you can just go though the plus minus supply as reference
    please refer to the following power supplies appeared earlier in this column.
    Dual Power Supply using LM 320 and LM 340
    40V dual power supply

  • kvs says:

    hi, to everyone.
    i again reply my problem in above (February 27, 2011 at 4:31 am)
    my transistors are slightly socked. and 100 ohm,2w resistors heating up. i check my all connections are correct.
    i have one doubt, should i connect the speaker one end+input signal one end+input supply(35v) com+input smps supply(230v) earth?
    now i’m earth one not connect in my circuit others all connected. should i connect earth with com?

  • Seetharaman says:

    Hi Momok Connect 100K potentiometer common (one end) to ground, slider of the potentiometer to C1 and input between ground and the other end (free end)of the potentiometer.

  • momok says:

    hi omer….
    thank you for the advice…
    it did work
    its awesome…
    it sounds really good… thank you admin.
    thank you omer…

    i only have one question…of where to put my potentiometer for the volume?
    ty

  • joenald says:

    ah..admin..

    can you post how did you solve for the resistor values?

  • Seetharaman says:

    Hi Bad Boy it should be a sealed enclosure, kindly seal the hole. make the cabinet air tight by using adhesive sealant on all joints.

  • Bad boy says:

    hai seetharaman i just built the box with te size 50*40*25 but i made a mistake i make an air hole of dia 4” .is it cause any problumee????????????????
    still the output is awesome.if any change is occur wether i seal that air hole??? anser meeee yaar

  • Bad boy says:

    dan use BC 547 in place of 108

  • omer says:

    hi MOMOK… no the thikness does’nt matter . your connections must b complete and accurate…. yes all the grounds should b commonly connected. . . . . just u can measure the current across all the transistors to know that if they r working or not??
    and also u can check by touching them if they r heating up then they r working………

    at the end , make sure that all ur connections are accurate…

  • momok says:

    hi omer.
    we have done the circuit. using BD140 and BD139 as substitute, as it was suggested on the previous post..

    but we have encoutered some problems

    -the output voltage on the output of the amplifier reach 17V…what do you think the problem was???
    -should all the grounds be connected as common one???
    -we have design the layout on pcb wizard on a 4 by 6 inch board will the thickness and distance of the connection from each other will give big affect?
    -how will we know if transistor is working?

  • dan46 says:

    pls can i usr c9 for BC108??
    pls email me on daniel_moses@ymail.com

  • dan46 says:

    pls can i use c945 for bc108 ??????????????

  • omer says:

    ho MOMOK…….. btw ur english is good dnt underestimate ur self man :P

    n ur alternatives are as…..

    2N3773 = 2N5303
    2N5294 = D313
    2N6107 = B857
    BC108 = BC109

    i hope u will find ……..

  • momok says:

    hello, thank you for this design, but just got problem looking for
    bc108
    2n6107
    and 2n5294

    is there any alternative replacement could you recommend to me,thank you,

    sorry for my bad english

  • kvs says:

    thanks OMER for your kind reply.
    i’ll go to check that and again reply to you are.

  • omer says:

    hi, KVS i think u r facing the connection problems…..
    plz check ur (( BCE )) connections of all ur transistors….

    i think u have wrongly connected ur (( B C E )) connections……..

  • kvs says:

    hi. have a good day to all.

    i have build this circuit.
    but it’s not working.
    100ohm,2w resistors are heating and the transistors are slightly socked when it touch.
    i can’t get where is the problem and what is the remedy.
    anyone knows to rectify this problem please explain me.

  • omer says:

    hi seetheraman ……. i have successfully designed this circuit …… i m using 20-025 power supply with 6800Uf capacitors with 3 amp diodes bridge …

    the amplifier is connected directly to my pc… the sound is good but there is lil bit hum sound which sometyms become loud…. i dnt know where is the problem and only one transistor is heating up others remain cool… where is the problem ???
    plz guide me setheraman i will wait for ur kind reply… thnkew :)

  • Seetharaman says:

    Hi Gopi the gain of the amplifier is around 70. To get 100Watt RMS your input should be 30 / 70 = 400mV RMS. To achieve you may to add one pre amplifier stage with a gain of 10 it should take care of your problem.

  • Seetharaman says:

    Hi Bad boy for a 12″ woofer an internal volume of 40 to 60 liters will be ideal. Center front mounted sealed enclosure of 50cm hight 40cm width and 20 to 25cm depth will be most suited. The wood thickness should be 20mm and inside walls should be covered with carpet felt or glass wool to avoid coloration of sound.

  • Bad boy says:

    sorry ..plz upload sub box size

  • Bad boy says:

    hai guyzzzzzzzzzz im successfully comlplete my amp .and buy a 12” subwoofer …if any one have the sub bod size please uploadd

  • gopy says:

    dear seetharaman,
    the amplifier output is very low, Q5 standing current is 30ma, output dc is -0.16v, all the transistors are very cool.at max volume Q5 collector current remains 200ma . o/p is nearly 20 watts only . what’s the problem. anyone fix the solution

  • inder says:

    my email id indercyprus at gmail

  • inder says:

    i am looking if someone help me buy this circuit or help me from start as i am new to this kinda stuff and all the stuff is available in India or not? os do i have to buy it from abroad

  • omer says:

    hey yar i m getting the out but its not clear… its notmuch louder and bass is also insufficeint ??

    wat should i do now ?

  • Bad boy says:

    superb ckt.you can use any voltage in between 30-0-30 up to 60-0-60 .if you try to make it plzz use heavy heat sink for power transistors.use bridge rectifiers insted of diods. use .33 ohm resistor having 5w or more.if you wired it well the out put must be awsome.im just enjoying this sub amp
    eryverybadboys@gmail.com

  • omer says:

    hii, i have designed this cct on the bread board yet …. but i m not getting accurate out put…. the output is a hum sound and low amplifiyng signal :( wat should i do now ? plz help me seetharamen ……

  • omer says:

    and i also want to know the pin layout of transistor 2N3773…. i will b very thankful to u seetheraman!!

  • omer says:

    hi seetheraman, how r u? i have a question about the subwoofer low pass filter…. is it connected to the input of the subwoofer circuit or at the output?

  • Seetharaman says:

    Hi Aris you can use ceramic or polyester capacitor for all except C17 which can be electrolytic or polyester as it is difficult to get in ceramic.
    HI Lordsville I can suggest a very simple cross over which is just sufficient Woofer through 300turns of 18SWG enameled copper wire (1mm dia wire will do)on 25mm dia plastic former wound for 40mm length. Mid range through 25uF non polar capacitor or 2nos 50uF electrolytic connected back to back and tweeter through 2.5uF non polar (here you can use a polyester or paper or 48″ ceiling fan run capacitor)or 2nos 5uF (4.7uF standard value) electrolytic capacitors connected back to back. I am using in my system an 8″ Philips 40Watts woofer, 6″ X 4″ Philips standard speaker as midrange and Philips 1″ Dome tweeter.

  • aris says:

    hello sir seetheraman,
    id like to build the subwoofer filter with left and right channel and a subwoofer out, id like to ask if those capacitors are ceramic.
    http://www.circuitstoday.com/subwoofer-amplifier

  • lordsville says:

    Thx a lot SEETHE::I have recently upgraded the transformers to dual 25v ac. Abt 50v. And it drives my 12-inch Sony speakers like mad but there is a volume limit so I wont damage them.Im thinking of buying Two 10-inch 8-ohms heavy magnet subwoofer speakers with tweeters and midrange speakers,,all 8-ohms.. to build 2 loudspeakers.Is this configuration convinient and do i need crossovers.do u know abt the best kind of crossover circuit i can use.

    Thx a lot.

  • Seetharaman says:

    Hi Aris you can use with sub woofer filter you have to increase input coupling capacitor to 2.2uF 50volt + terminal connected to Q1 Base. with 0.22uF low end cut off will be around 90Hz to still better low frequency response you have to increase the value of C1 to 2.2uF

  • omer says:

    hi every one , if you people want more amplifier projects then visit this link it will help you !!

    http://www.youtube.com/watch?v=OcoLE3epPYI&feature=feedwll&list=WL

  • aris says:

    thanks for all the support sir! this project is really great, of course with your support! thanks a lot!

  • aris says:

    hello sir seetheraman,
    i found my problem, it was Q3 and Q4 mounted on the same heatsink with their screws un-insulated, i removed the other one now it works fine!
    just as you said, the sound is clean and nice! will it give a good bass if i will connect it with the subwoofer filter?

  • omer says:

    thanks seetherman ………. thanks a lot man …..

  • Seetharaman says:

    Hi Lordsville As indicated 15-0-15 2000mA transformer will be 30VA normally. With a full wave rectifier it will give 15 volt ( a peak of 21volt DC)at 2Amp DC. even if you take full winding 2amps then it be just 60VA.If the efficiency of the amplifier is around 80%(cannot be this high) you can get 48 watts energy. that is just 24 watts per channel. For a good punch for a room of 20ft by 12 ft by 10 ft you require 60 watts RMS per channel for a good punch. You have to first upgrade amp and then the speakers. Amplifier rating can be always higher than the speaker capacity for a clean sound.

  • Seetharaman says:

    Hi Omer the provider is correct he has given the best equivalents. you can go ahead.
    Hi Aris Once the assembly completed and thoroughly checked for mistakes, before energizing do not connect the speaker use a 100 ohms 10 watt resistance in its place. Temporarily link Q4 and Q6 bases. Now switch on with +35 0 -35 supply to the circuit without feeding any signal to the amplifier. check the current drawn by the circuit from positive and negative rail should be less than 50mA. the voltage across the 100 ohm resistance can not be more than few milli volts. if it is more check the connections and polarity of transistors and diodes, correct the mistakes and energize. If every thing is ok remove the base link by measuring the current at the collector of Q5 it should be between 60 and 100mA if not by varying R9 & R10 you can achieve. Once things are set feed around 50 to 100mV audio signal through a suitable volume control the sound should be clean and with life.

  • aris says:

    hi sir seetharaman. i checked the Q3Transistor (2sb825 in place of 2n6107) and noticed that the pins were interchanged, i corrected it but when i powered it, it burned my 4ohms,80watts speaker. i checked the output voltage it sends the supply voltage when the speaker is connected. there is also a voltage at the input pin which is about 12volts dc.
    what happened sir. i never used my speaker before so i used it to test this project but sad to say it ended up burned.

  • aris says:

    by the way sir,i used a cd player for testing but there is no output and when i touched the input terminal i still hear no blurring sound just like any other amplifier. hope you could help me solve it. tnx again sir!

  • aris says:

    hello sir seethraman, i have built this amplifier but there is no sound coming out. ive used 2sb825 in place of 2n6107.2sd313 in place of 2n5294 and 2sd667 in place of bc108. i used .22 electrolytic at the input. all other capacitors and resistors used are those of specified. what might be wrong sir? i have not used those BD series but ill try to find it if those replacement i used are wrong. thanks in advance sir!

  • omer says:

    hi mr. seetherman …..

    my question is personally for u….

    i m from pakistan and i didnt find any of the transistors used in this circuit but the provider gave me thier equivalent transistors … i did’nt have designed this circuit cz i want to confirm that these equivalents are suitable for the circuit or not ……..

    equivalents are as follows….

    2N3773 = 2N5303
    2N5294 = D313
    2N6107 = B857
    BC108 = BC109

    i will b very thankful to u ….. n will wait for ur kind reply… thnx.. :)

  • lordsville says:

    hello evry1
    i bought an amp panel with a label :hi-ft ok 100w: powered by a 15v-0-15v 2000ma transformer.it has an aux. Input and 2 mic. Input.it also has mic. Volume ctrl. Bass and treble ctrl and master vol. Ctrl. It works ok with 2×80-watts,6-ohms,5inch Sony deck speakers but Im not satisfied wt the audio depth and bass.im tnking of upgrading d speaker to 2x12inch double magnet subwoofer spkrs wt abt 8-ohm rated abt 200watts paralleled wt tweeters. Will it work wt my power supply and what modifications do I need to make?

  • kingsly says:

    Hey seethraman thax a lot dude i repaced my transformer with a center tap 1 and its working well.
    Sound is not so clear wat replacements are to be made kindly tell.
    i replaced c1 with 4.7uf
    wat else to be replaced

  • kingsly says:

    any ways 40volt is not to high for it na ?
    i will get it center taped if its ok

  • kingsly says:

    no dude its a 28 volt 5amp transformer so 40 volt dc but not center tap
    thax a lot for the info i will try and let u know

  • Seetharaman says:

    Hi Kingsly you require a centre tapped transformer 25-0-25volt of 125VA rating. speaker one should be connected to 0 volt other end of speaker to output transistors. you have to connect plus 35 volt as well -35volt to amplifier that is a total of 70 volt DC.

  • ARIS says:

    tnx sir seetharaman. ill see if can get those replacement.

  • francis says:

    can i use 2s transistors?

  • kingsly says:

    do i need a center tap transformer for ground or normal 1 will work

  • kingsly says:

    Hey seetharaman i have built this circuit but iam not geting any output at speaker my input is +40v 5amp
    i have connected the ground of my speaker to the ground of r1
    when i connect the ground of speaker to +40 input it give humms but no sound output
    my speaker is 8ohms 100w

  • kingsly says:

    plzz plzz help me fast i will be doomed if it dosent work out

  • kingsly says:

    the speaker is giving hum but no sound when the ground of speaker is given to +40 input

  • kingsly says:

    Hey Seetharaman i am not geting any output my input voltage is 40v 5amp will it effect the circuit
    I have connected the speakers ground to R1 ground

  • Seetharaman says:

    Hi Aris 2N6107 can be BD140, 2N5294 can be BD139 and 2N3773 can be BD182 or the standard 2N3055
    Hi Caloy if amplifier output and input terminal are close positive feed back can take place and you may get instability. the power supply input output terminals may not matter much they may produce little hum if filtering is not proper.

  • CALOY says:

    wat will happen if the output terminal and the input terminal for power supply is near from each other???
    hum noise???

  • franc says:

    are there any replacement for the transistors other than 2n series sirs?

  • aris says:

    or the driver transistor if u have sir,pls.

  • aris says:

    can i ask any substitute for all the transistors specifically sir seetharam?

  • Anmol says:

    Thanx a lot jojo sir. . . .bt wil u plz b in touch wid me 2 clear my doubts. . .plz sir i nid ur help. . .sent me ur email id at crackeranmol@gmail.com. . .n 1s again hearty thank u fr gvng me suggtn. . .

  • Anmol says:

    Seetharam sir plz help me. . . .plz rply 2 me or atleast gve me ur email addr. .plz sir help me. .

  • omer says:

    hey yar ………… can any one telL me that how can i able to convert 12V to 35 V dc????????

    i have 12 v transformer with 2A

    and another question …….. wilL this circuit work purely as a subwoofer output i.e with no stereo or voice sound only bass ??????????

  • Anmol says:

    Seetharam wil u plz help me out in builting dis circuit. . .actualy m a beginer i dnt knw anythng but i hve very much interest in such circuits so wil u plz teach me i dnt even knw hw 2 read a cicuit diagram im a be 1st yr student of etc branch plz help me friend

  • CALOY says:

    hey jeffrey, this is a difficult project for beginners.

  • jeffrey castillo says:

    pwd hingi ng pcb design…. baguhan plang ksi ako guzto ko ma 22ng gumawa nang ganito

  • seetharaman says:

    Hi Narendra you can use SG3524 chip
    http://focus.ti.com/lit/ds/symlink/sg3524.pdf

  • narendra says:

    is there any circuit which would give 35 volts from 12 or 24 volts

  • Nilanjan Roy says:

    thanks for support me

  • dan46 says:

    is this amplifier really woking?

  • Seetharaman says:

    Hi Tomin You are correct but you have to develop plus & minus dual supply for TDA2020 with inverter or other gadgets, but LA4440 is working with single 14 volt supply rail available in car and 19watts RMS inside the car is enough power for sub woofer.

  • Tomin says:

    TDA2030 amplifier circuit is ideal for driving low frequency subwoofer speakers in home theater systems. The circuit is quite simple and can drive large cone speakers without much distortion.
    http://circuitsector.blogspot.com/2010/09/200w-tda2030-subwoofer-amplifier.html

  • Seetharaman says:

    Hi Prem use Sanyo LA4440 for your application which is best suited as it produces 19watts RMS into 4 ohms speaker with quite low distortion.

  • Seetharaman says:

    Hi Prem LA4440 is the best suited amplifier with 19watts RMS power into 4ohms speaker with car battery supply without inverter or coverter.
    http://www.datasheetcatalog.org/datasheet/sanyo/LA4440.pdf

  • PREM says:

    CT is quite awesome & informative…
    THANKS A LOT SIR…

  • prem says:

    Thank you very much sir….
    :-)

  • Seetharaman says:

    Sanyo LA4440 is the best suited amp with an output of 19watts RMS into 4 ohms load in the bridged operation mode.
    this is the most rugged ic for direct car stereo operation.
    http://www.electronica.ro/audio/LA4440.shtml

  • prem says:

    Helo sir
    Pleas reply me…

  • prem says:

    Could you please give me 12v supply sub woofer power amplifier…. For car stereo….
    Iam waiting for your reply…

  • prem says:

    Please sir Iam waiting for your reply…

  • prem says:

    Hello sir,
    Could you pls give me 12v supply subwoofer amplifier circuit.. For car stereo…

  • Seetharaman says:

    Hi Patrick you require a 25 – 0 – 25 volt 5amps this transformer will give you 250VA. use individual bridge rectifier and smoothing capacitors in each amplifier PCB to reduce cross talk. you require 5amp bridge with 2 nos 4700uF and 2 nos 0.1uF for each amplifier. run ac wires from transformer with not less than 18SWG wire to each amplifier.

  • patrick vaz says:

    Power supply for 100watts subwoofer & 2×60 watts amplifier

    Hi Seetharaman,
    I want to have a common power supply for both the above mentioned subwoofer and 2×60 watts amps, what should be the transformer with ampere rating, power supply circuit diagram.
    thanks

  • Seetharaman says:

    Hi Billy
    http://www.eleccircuit.com/power-amp-ocl-100w-by-transister-mj15003mj15004/
    you can use this PCB with small modification.

  • Billy says:

    Hi

    Does anyone know a link where there is a PCB design of this circuit.

  • Seetharaman says:

    Hi Saju Congratulations.

  • saju says:

    hi seetharaman

    I have assembled the circuit and working fine

  • Seetharaman says:

    Hi Inder you want the kit or fully assembled and tested. you can contact me seethasub@hotmail.com

  • inder says:

    i am intersted to buy this circuit without power supply can any 1 intersted to send me i wl pay i am from India

  • Jacob says:

    hello seetharaman

    you asked me for the voltages

    do the voltages are correct?

    At Q1 Emitter -1.2
    Collector 46.2
    Base -0.06

    At Q2 Emitter -1.2
    Collector 46.9
    Base -0.06

    At Q3 Emitter 46.3v
    Collector 1.2v
    Base 46.8v

    At Q4 Emitter 0.7v
    Collector 46.5v
    Base 1.2v

    At Q5 Emitter 0.03v
    Collector 47v
    Base 0.07v

    At Q6 Emitter 0.3v
    Collector -46.5v
    Base -0.1v

    At Q7 Emitter -47.4v
    Collector 0.03v
    Base -47.1v

  • Jacob says:

    hello seetharaman

    At Q1 Emitter -1.2
    Collector 46.2
    Base -0.06

    At Q2 Emitter -1.2
    Collector 46.9
    Base -0.06

    At Q3 Emitter 46.3v
    Collector 1.2v
    Base 46.8v

    At Q4 Emitter 0.7v
    Collector 46.5v
    Base 1.2v

    At Q5 Emitter 0.03v
    Collector 47v
    Base 0.07v

    At Q6 Emitter 0.3v
    Collector -46.5v
    Base -0.1v

    At Q7 Emitter -47.4v
    Collector 0.03v
    Base -47.1v

  • Seetharaman says:

    Hi Mounica they are not equivallents and cannot be used. 2N series is freely available hence can be used.
    Hi Jacob the circuit is correct as both the output transistors are NPN. Q4 and Q6 are complimentory drivers

  • Jacob says:

    Hi seetharaman

    I think for Q6 100ohms resistor should be connected to emitter

  • mounica says:

    can i use BD139,BD140 or MJE340,MJE350 instead of 2N6107 and 2N5294

  • Jacob says:

    hello seetharaman

    At Q1 Emitter -1.2
    Collector 46.2
    Base -0.06

    At Q2 Emitter -1.2
    Collector 46.9
    Base -0.06

    At Q3 Emitter 46.3v
    Collector 1.2v
    Base 46.8v

    At Q4 Emitter 0.7v
    Collector 46.5v
    Base 1.2v

    At Q5 Emitter 0.03v
    Collector 47v
    Base 0.07v

    At Q6 Emitter 0.3v
    Collector -46.5v
    Base -0.1v

    At Q7 Emitter -47.4v
    Collector 0.03v
    Base -47.1v

  • Jacob says:

    please give your mobile number to talk with you personal

  • Seetharaman says:

    with respect to zero volt at collector base and emitter of all the transistors and also across bias diodes

  • Jacob says:

    all voltages means where i have to see

  • Seetharaman says:

    Hi Jacob by shorting R9 and R10 if the current is not falling down check your circuit again and try to send me all the voltages, for me to understand your problem.

  • Jacob says:

    please reply

  • Jacob says:

    Hello seetharaman output transistors getting too hot Q5 and Q7

    i adjusted bias current by trim-pot instead of R9 and R10 but still getting heat but drivers are running cool

    i have used 8inch length and 3inch wide aluminium heat sink was this sufficient?

    please solve this problem the amp producing too much heat.

  • Jacob says:

    Hello seetharaman output transistors getting too hot Q5 and Q7

    i adjusted bias current by trim-pot in place of R9and R10 but still getting heat but drivers are running cool

    i have used 8inch length and 3inch wide aluminium heat sink was this sufficient?

    please solve this problem the amp producing too much heat

  • Seetharaman says:

    Hi Jacob all other parts are OK go ahead building

  • Jacob says:

    why dont you tell this first

    all the remaining part of the circuit is ok or not

  • Seetharaman says:

    C3 polarity is OK.

  • Jacob says:

    what about c3 that means polarity

  • Seetharaman says:

    Hi Jacob C2 polarity is wrongkindly connect -ve lead of capacitor to R4 and +ve to ground.
    With the above correction it should become alright.
    if output is still going negative try adjusting R11 till it becomes zero.(give alteast 15 minutes for warming befor doing the adjustment).

  • Jacob says:

    hello seetharaman C2 (4.7uf 100v)is getting bold and then it is exploding after several minutes why it is happening like this DC offset voltage is getting negative voltage

  • Jacob says:

    i have used same as 40v dual power supply circuit appeared in this site

    what do you mean by regulated power supply

  • Jacob says:

    if use it on Q4 what will happen?

    sorry for many questions

  • Seetharaman says:

    Hi Jacob C2 is correct it is only the bypass capacitor for Q1 Q2 collector current.
    560 PF at Q6 may not have the required effect as it will give feed back to only one half of the waveform that is conduction through Q6, Q7 not through Q4, Q5.

  • Jacob says:

    i think c2 should be of same value

  • Jacob says:

    what will happen if i use 560pf at Q6

    if output DC voltage is 330mv do this spoil the speaker

  • Seetharaman says:

    Hi Jacob capacitor C5 is used to roll of the high frequency response of the amplifier. it will be a negative feedback only at high frequencies. if increase the value the HF response of the amplifier will fall down as though you have cut the treble control. the value should be chosen such a way the amplifier response is limitted to audio frequency only( so that you can avoid HF instability)
    There wont be any change in the out put DC voltage only the AC voltage will change. if DC changes your amplifier power supply is not regulated properly. if DC is constant the amplifier is quite stable in DC conditions and it indicates the design is good.

  • Jacob says:

    forgot to ask another question what is the use of capacitor C5
    please read above comment also

  • Jacob says:

    seetharaman actually you didn’t understand my problem

    Problem 1:output offset voltage is increasing gradually before it was at 96mV but now it is around 380mV

    Problem 2:while playing songs at low sound the out voltage is same i.e 380mV.At maximum sound also it is showing same voltage how it is possible

    I am measuring output voltage with digital multimeter +ve terminal connected to K1 and -ve connected to earth

    Question:what will be the output voltage at full sound?

    please please understand my problem and question

  • Seetharaman says:

    Hi Jacob you ar right. The gain of the amplifier is R6 / R5 that is 47K / 680 ohms. around 70. for 20 volt output you require only 20 / 70 = around 285mV RMS any pre amp will give you this much even the walkman or any digital MP3 player can give. check these resistance values and the capacitor C3. kindly increase the input coupling capacitor to 2.2 or 4.7uF 0.22 is not sufficient. Reduce C5 to 100PF. These should solve your problem.

  • Jacob says:

    i have build this circuit (not assembled in a case) i have directly connected from cd player (not from sub woofer out) sound is good but getting low sound even at maximum volume i have used MPSA43 instead of BC108 because i don’t have them anyway this amp is very nice but low sound i think you can solve this problem

    output voltage is also increasing with out input signal at first it is 96mv but now it is 330mv

    when measuring output voltage while playing a song at maximum sound its voltage is same ie 330mv to 380mv
    For 100 watt it should get atleast 20v in multimeter

  • Jacob says:

    Thank you seetharaman for your reply

    i have build this circuit (not assembled in a case) i have directly connected from cd player (not from sub woofer out) sound is good but getting low sound even at maximum volume i have used MPSA43 instead of BC108 because i don’t have them anyway this amp is very nice but low sound i think you can solve this problem

  • Seetharaman says:

    Hi Jacob it requires a sub woofer filter. it can be connected directly to 5.1 DVD / VCD player’s sub-woofer output without any filter or preamplifier

  • Jacob says:

    Does this amp require preamp

  • seetharaman says:

    The enclosed is the best uited mic mixer. for aux you can use one more 741 with input and feedback resistance as 100K and cnnect it to the existing mic 741 pin 6.
    http://www.aaroncake.net/circuits/mixer2.asp

  • joel says:

    Hello Seetharaman

    could you please give me preamplifier circuit that it should have 2 AUX (100mV/470Kohms) and 2 Dynamic Mic inputs at 1K

    I request you the above circuit on 1st Aug,you told me that you will send soon but till now there is no response from you

    I am waiting for your reply

  • seetharaman says:

    Hi JB you can refer to 40V dual power supply appeared earlier in Circuits today. use 24 – 0 – 24 volt transformer with 125VA rating, instead of 30 – 0 -30.

  • seetharaman says:

    Hi JB You can use a 25 0 25 transformer with 150 VA capacity a 5 amp bridge rectifier and two filter capacitors of minimum 4700uF 50 volts with 0.1uF 100 volt ceramic capacitor in parellel with it in both positive and negative supply.
    rrefer to 40V dual power supply appeared in these column earlier

  • joel says:

    Hi Seetharaman

    could you please give me preamplifier circuit that it should have 2 AUX (100mV/470Kohms) and 2 Dynamic Mic inputs at 1K

    I request you the above circuit on 1st Aug,you told me that you will send soon but till now there is no response from you

    I am waiting for your reply

  • seetharaman says:

    Hi PravinSP sorry for the delay. the circuit enclosed is for your sub woofer filter. connect left and right channel input to this filter in addition to your LA4040 amplifier, and the output of the filter to subwoofer amplifier. The existing LA4040 will become your front right and left channels 2. and the subwoofer will be your .1 channel.
    http://www.free-electronic-circuits.com/circuits/low-pass-filter-subwoofer.html
    you keep your LA4040 amps bass control little up so that it cannot respond to freq below 120Hz and enjoy the full thumping bass response.

  • pravinsp says:

    I had put an request on 23rd Aug 2010, I was wainting for your reply to start the project with..since then NO reply…Very Interesting…!!!

  • jb says:

    sir, can you give me the power supply circuit so that its easy for me to assemble.. thank you.

  • jb says:

    how to make the power supply for this woofer?

  • pavinsp says:

    Hi Seetharaman, I want to make this circuit, I find it very insteresting as I have stereo amp made up of LA4440 and want to make a Subwoofer, to make my system 2.1. also tell me the circuitry for low frequencies, as input for 100Wtt Subwoofer Amp. Please could you send me it’s Clear Schematic and PCB to my mail ic – pravpawar@yahoo.co.in

  • emmi says:

    hello seetharaman i have send you mail(seethasub@hotmail.com) with attachment having circuit diagram of amplifier please read the mail and reply me soon

  • mounica says:

    what is the THD value of this

  • seetharaman says:

    Hi Emmi Q3 also requires a good heatsink as being a driver transistor. 80volt pk tp pk avilable for the speakers. the RMS value becomes 28volt(ignoring the voltage drop across output transistors around 3volts) power = V sq / Z (spkr imp)
    28 X 28 / 8 = 98 watts approx. with 4ohms it will be 196watts(approx). Power supply must be capable of giving 3.5amps current. Fix a good heat sink for output transistors.

  • A.A.ABDUL says:

    Hi seetharaman,pls i need a preamp 4 this diagram on my mail(aaabdul86@yahoo.com

  • emmi says:

    Hi seetharaman

    i put trim pot between emitters of t1 t2 and adjusted offset voltage and also put 2.2k at r11
    sounds nice thanks for you reply
    but q3 is getting hot and q4,q6 are not getting is this normal

    i have put +/-40v to this circuit what will be the power rated at output how do you calculate

    can i use two 100watt speakers in parallel having impedance 8 ohms each

  • seetharaman says:

    Hi Emmi fix a variable resistance temporarily for R11 say 5k 5W. adjust till you get zero voltage at out put. fix anearby preferred value. check the current drain of both supply rails without input signal itshould be within 100mA.

  • emmi says:

    hi seetharaman

    the out put is getting nearly 1 volt at no input this is very high how can i decrease this
    i think we have to add 100r in parallel with diode at emitter of Q6 to adjust instability of Q7 because its getting heat

  • seetharaman says:

    Hi Pravinsp i was away on a pilgrimage and back. unfortunately my desk top is down. i can do drawing etc on it. now for email i am using my inspiron mini. please bear with me for few more days i will send you the circuit as well to Mr. Adnan on variable power pack.

  • pravinsp says:

    I had put an request on 23rd Aug 2010, it seems since then your were not online. I was wainting for your reply to start the project with..but on 30th Aug 2010, you were online and just one reply to Mounica…Very Interesting…!!!

  • seetharaman says:

    Hi Mounica you can connect a zobel network (of 10 ohm in series with 0.1uF) in parellel to K1 loudspeaker.
    Vi limitter can be provided just before the capacitor C1.

  • mounica says:

    Hello seetharaman

    How can i add vi limiter and zobel network to this amp please tell me

  • emmi says:

    hi seetharaman i have build this circuit but Q5 is getting too hot at no input i found that voltage across r16 is high and also humm sound is coming

    why it is happening like that i checked everything all transistors are working perfect

    help me please

  • emmizeb says:

    Hi seetharaman i have build the above circuit the problem is q5 getting hotter and a humm sound is coming at output i found
    voltage across r16 is higher at no input

    what will be the problem ? i have checked everything all transistors are working
    help me please

  • pravinsp says:

    Hi Seetharaman, I want to make this circuit, I find it very insteresting as I have stereo amp made up of LA4040 and want to make a Subwoofer like 2.1 sound system also tell me how circuitry for low frequencies as input for 100Wtt Subwoofer Amp. Please send me it’s Clear Schematic and PCB to my mail ic – pravpawar@yahoo.co.in

  • shreya says:

    I found that voltage across the R14 is greater than R16 thats why Q7 is getting hotter than Q5

    If i increase the value of R11 (as you said) what will happen?
    voltage at R14 will decrease or not?

  • seetharaman says:

    Hi Shreya increasing R11 to 2.7K to 3.3K should solve your problem.

  • shreya says:

    Hi seetharaman where you have gone all these days

    i shorted R9 & R10 the temperature of transistors decreased but Q7 is getting hotter than Q5 why ?

  • abhishek says:

    Hello mr.seetharaman ur doin vry fine job by helpin people coz at times we are really clue less about the fault. so thanx a lot ………I wanted to ask u few things please suggest me …….i willb really thankfull to you
    iam makin this circuit and iam using transistor 6110 in place of 6107 and 5296 in place of 5294.
    please tell me will they work!! coz the actual values arent avialable here.
    and i have auto variable transformer which has a output range of 0-220 volts at its output it can give any o\p from 0 to220 volts and current ratig of 8 amps.please tell me how i can use this as it has no ground point. please tell me as soon as possible mail me if can .

  • edits says:

    hi can i ask you something regarding in this circuit

  • shreya says:

    Hi seetharaman

    i found 3input mic pre amplifier
    can i use that for two amplifier if so how can i

  • luky1020 says:

    sir i have an strio amplifier circuit i want to build three chanal circuit 2 speeker and 1 woofer.
    spouse i have three mono amplifier in same condition.
    can you help me about it? plz
    how to convert my circuit for woofer?
    how to convert from 2 input to 1 out put?
    if you give me diagram i will be very very thanks

  • mounica says:

    Hi seetharaman
    i am asking about R8 not R9 and R10
    if i increase or decrease R8 what will happen?
    if i increase or decrease R13 and R15 what will happen?
    if i increase or decrease R14 and R16 what will happen?

  • seetharaman says:

    This amplifier is a class B amplifier. that is it will conduct only when input sgnal is present(an ideal class b amp.
    If you use only D1 then if the input to out put pair is greater than 600 mV only it will conduct, up to that no conduction will take place. if you see the output waveform by feeding a sine wave input, the discontinuty at zero crossing. this is called cross over distortion.
    r9 and 10 are used to avoid the above phenomena by having a small conduction in out put pair. if you increase thiese resistance value the no input signal current through out put pair will increase. if you reduce the current will reduce but the cross over distortion may set in.

  • mounica says:

    Hello seetharaman
    i have some doubts could you please clarify
    this is what type(class) of amplifier?
    if i remove d2 what will happen?
    if i increase or decrease R8 what will happen?

  • seetharaman says:

    Hi Mounica the amplifier will become Class A amplifier. Out put transistors require a very large heat sink.

  • mounica says:

    if i add one more diode to d2 what will happen

  • shreya says:

    Hi seetharaman i shorted R9 & R10 the temperature of transistors decreased but Q7 is getting hotter than Q5 why ?

  • seetharaman says:

    HiJoel MPSA 42 is a better transistor to 43. i will send soon.

  • Joel says:

    Hi seetharaman

    MPSA43 is not available can i use MPSA42?
    could you please give me preamplifier circuit that it should have 2 AUX (100mV/470Kohms) and 2 Dynamic Mic inputs my e-mail address joelchristii@gmail.com

  • seetharaman says:

    Hi David It is very high. please check the wiring around Q3, Q4, Q5. Q6 and Q7.
    My prototype consumes around 100mA standing current. (no signal current)

  • david says:

    Hi seetharaman i shorted R9 and R10 but the standard current is not reducing it is around 800mA what i have to do now

  • seetharaman says:

    Yes Emmi no signal current drain.

  • emmi says:

    Hi seetharaman

    what do you mean by standing current?

    the intake of current to the amplifier at +/- rail at no input signal right??

    please explain me i am new to electronics

    can you send your mobile number to my mail i have to ask some doubts emmizeb@gmail.com

  • seetharaman says:

    Hi KVS you can use. The DC will be 34 0 34 that is the most suited. if dc shown is x volts your transformer has to be x X 0.7, speaker impedance 8 ohms is preferable. 4 ohms can be used, use fast acting 5 amp fuse in both plus and minus supply.
    Hi Emmi PCB is not available. other project one is available on the net, which you can adopt. i will send it to your email id. The only standing current is adjusted to 50 to 75mA depends on the out put transistor matching, by varying R9 and R10 from 10 ohms to 27ohms

  • emmi says:

    Hello seetharaman
    Please read my comment dated July 29,2010

  • kvs says:

    hi seetharaman please reply me.
    i have 24-0-24v, 6A power supply.
    And my subwoofer rating 100w, 4.8ohm.
    May i use this power supply for this circuit?

  • seetharaman says:

    Yes short them

  • shreya says:

    I don’t understand “put a link for R9 and R10″ what do you mean by link?

    shall i shot them

  • kvs says:

    i didn’t have 35-0-35v transformer in my area.
    can i use 24-0-24v, 6A for this circuit?
    anybody reply me please.
    And i have 100w sub woofer & it shows 4.8ohms between it’s two lead.

  • seetharaman says:

    Hi put a link for R9 and R10
    between C1 and R1 add 2.2 k resistance
    add 470 PF in parellel with R1.
    use a good quality shielded wire and connect to mp3 player through a 100k log volume control

  • shreya says:

    Yes seetharaman the output transistors are getting heated up without input signal

    Without any input signal the speaker is quiet but when i give input signal burring sound is coming

  • seetharaman says:

    Hi Shreya whether it is burring sound or motor boating sound. Without any input signal the speaker should be quiet. Whether output transistors are getting heated up.

  • emmi says:

    sitharaman

    how to test this amplifier like adjusting bias current etc….

    you didn’t give any notes

    do you have PCB design? if it has can you send it to my mail emmizeb@gmail.com

  • rambabu says:

    Hello seetharaman

    i think R14 must be connected to collector of Q7 once check the diagram

    also tell me where should i use variable resistor of what value to adjust bias current

    sorry for my poor english

  • shreya says:

    Hi! seetharaman

    when i touch the input a barrrrrr sound is coming i thought that it is working but when i give input signal thru mp3player disturbance is coming and still barrr souund is coming
    i gave +/- 48v at 5 amperes to the amp
    please help me

  • seetharaman says:

    Hi Mounica its quality is quite good. you please go through my earlier comments on the modification required

  • mounica says:

    is the quality of the output is good??

  • seetharaman says:

    Hi Mounica it is a general purpose low audio frequency amplifier to be used with proper subwoofer filter

  • mounica says:

    This is what type of amplifier

  • di2k says:

    Hi Seetharaman

    I already builts some subwoofer above but the audio result
    was not so good !
    Would you like explain me and answer my qustions :
    - what are we using the power rated subwoofer speaker same with the power rated output of the amplifier ?
    - why the quality of sound was different if i changed the input source,example tv and radio or many type of tv audio
    out ?

    thank alot
    br
    di2k

  • seetharaman says:

    Hi David it is measured at the collector of Q5. Actual currnt depends of the component manufacturers production spread . All the specimens assembled cannot have identical values. To set it correctly feed 1KHz sine wave signal to the input of the amplifier and feed output to rated load and also connect it to an oscilloscope adjust the quiescent current till there is no discontinuty in sine wave at zero crossing point. it can be anything from 20mA to 200mA as per the matching of the compoung complimentry output transistors.

  • Biman says:

    Hi can any one give me circuit diagram of 2 channel to 5.1 channel sound conveter

  • David says:

    what is quiescent current actually ? How and where it is measured

  • tharindu says:

    Hi Seetharaman,
    I want to know this circuit how output frequency in this circuit???????????????????????????????

  • seetharaman says:

    Hi Shreya around 60 to 100mA depends on the components.

  • shreya says:

    what is the quiescent current of this circuit

  • Biman says:

    Hi Seetharaman,

    Can you give me the circuit diagram of
    streo to 5.1 channel converter.

  • eldejay says:

    I have an Infinity BU-120 subwoofer that has a bad amp. Can I use the factory installed RC connectors, off/on switch, phase switch and the like with this board?

  • Soumya Sumitra Behera says:

    Hi Seetharaman

    Can u please wtite me the name of the parts for http://electroschematics.com/103/40w-audio-amplifier-tda2030-bd712-bd711/-(What-resistor, capacitor, diode, IC chip). I cant understand from the c.diagram. Pls tell me what will be preferable for input voltage? Can i use simple circuit board which have many holes in it and we have to solder 1 by 1?

    Please show me how to construct 5.1 home theater. I have the speakers only. (Schematic Diagram)

  • seetharaman says:

    Hi Soumya in 5.1 system you have to use 5 amplifiers and speakers. sub woofer will be a single channel amplifier only. low bass notes have no directivity they are not heard but felt. hence mixing both channels and using a suitable low pass filter you can get the low notes amplified through subwoofer amplifier. thisd project givs only the subwoofer amplifier portion.
    Hi monica you can use NE555 timer with the relay it has appeared in electronics today earlier.
    hi Shreya you can use this for any application as i informed earlier only a small modification is required, increase C1 to 4.7uF and reduce C5 to 47 to 100PF. before C1 provide a volume control

  • shreya says:

    Hi Seetharaman

    can i use this amplifier for keyboard and guitar

  • mounica says:

    Hi seetharaman

    can you please give me the circuit diagram of five seconds timer

  • Soumya Sumitra Behera says:

    Sir, i really really thanku from my heart. Thanku for your kind circuit diagram.
    http://electroschematics.com/103/40w-audio-amplifier-tda2030-bd712-bd711/
    Can u please wtite me the name of the parts-(What-resistor, capacitor, diode, IC chip). I cant understand from the c.diagram. Pls tell me what will be preferable for input voltage? Can i use simple circuit board which have many holes in it and we have to solder 1 by 1? Usually sub woofer has 2 RCA for Stereo Input and 6 RCA for 5.1 Input and 5 RCA for Output(Center, Front and Reer) Are these are Included in this circuit?

  • seetharaman says:

    Hi Monica initially you will be connecting the amplifier output to a resistance, for the output coupling capacitor inside the amplifier to get charged. In 5 seconds it will get charged. once it is fully charged you can connect the amplifier to speaker without the click problem.
    to do this automatically when ever you switch on the amplifier, the resistance will be connected to the amplifier output through the timer, once the required time is lapsed the timer will connect the speakers to the amplifier by disconnecting the resistance.

  • mounica says:

    Also Tell me that 5 second timer

  • mounica says:

    Hi seetharaman

    i didn’t understand whare i have to connect 100ohms resistance and switch

    please explain me

  • seetharaman says:

    Hi Shreya you can use any transformer with 1.5 amp are greater. 1.5amp is sufficient. if you have 5 or 10 amp you can use it. still at higher volumes the consumption cannot be more than 1.5amps. Then why we prefer the current rating. since if you inadvertently short the amplifier output nothing will happen to the amplifier with higher rating transformer the current drawn by the out put transistor can reach the maximum capability of the transformer and will get destroyed to avoid it use a fast acting 1.5amps fuses in the power supply both positive and negative supply rail.
    Hi Mounica A simple solution will be conect the speaker through a switch, first connect the amplifier to 100 ohms resistance and switch over to speaker after 3 to 5 seconds, this will enable the out put coupling capacitor to get charged and the thump can be avoided.
    You can also use a 5 second timer to do this job.

  • mounica says:

    Hi seetharaman

    i have an ahuja 100watt amplifier when i switch on a big sound “pat” is coming out of speaker how can i prevent this sound

    thanks

  • shreya says:

    Hi Seetharaman

    can i use this amplifier for keyboard and guitar

    also need some clarification about using transformer
    i have 35-0-35 5A transformer
    i will use 16ohms load
    but you told to joe to use 1.5A
    because i don’t have 1.5A
    if i use 16ohms load at 5A any problem will occur please let me know clearly

  • Soumya Sumitra Behera says:

    And also sir cant we have volume control for it.
    I connect Front speaker=10Wx2, Reer speaker=10Wx2 and center=10W.

  • Soumya Sumitra Behera says:

    Sir, i really really thanku from my heart. Thanku for your kind circuit diagram. Can u please tell me the name of the parts-(What-resistor, capacitor, diode, IC chip). I cant understand from the c.diagram. Pls tell me what will be preferable for input voltage? Can i use simple circuit board which have many holes in it and we have to solder? Where should i connect front and reer speaker pins? Pls teach me in detailed…Pls…Pls…Pls

  • seetharaman says:

    Hi David check the polarity of bias diodes D1 and D2. short R9 & R10 and check the standing current, may come down to just few mA, without any signal input to amplifier. at low volumes it may sound highly distorted. you can adjust these values to increase the standing current to 50mA or so. By shorting R9 & R10 if the current not reducing, then there is some wiring mistake kindly check up thoroughly.

  • seetharaman says:

    Hi Soumya you can use the motional feed back amplifier apeeared in Circuits today, which will be most suited for your application and your speaker.
    you can use TDA2030 with 2 complimentry transistors to get 40watts into 4 ohms speaker(you must always use a little higher power amplifier than what the speaker can handle)
    http://electroschematics.com/103/40w-audio-amplifier-tda2030-bd712-bd711/

  • Soumya Sumitra Behera says:

    Dear Sir,
    I gota 30 W, 4 ohms speaker for sub-woofer. I am going on scarping my head. I dont know how to construct the amplifier for it. This sub-woofer is going to be used in 5.1. Please show me the way to construct this. Please provide me your kind guidance, by the circuit diagram and the parts to be used and where to be used. I am a beginner. Pledging your kind reply.

  • David says:

    Dear sitharaman

    Thanks for your kind reply

    i found that bu407 is npn and 2n6107 is pnp

    anyway i changed to 2n6107

    but the transistors which are in the output(Q5 and Q7) are getting to hot

    when we touch the heat sink our finger will burn out that much heat is coming from them

    it is getting hot with in few seconds

    i am using 32-0-32 5A transformer

    let me know what changes have to be made to the circuit

    reply as early as possible brother..

    thank you

  • seetharaman says:

    Hi David all your component selections are ok. 40 volt power supply published is the correct one only change is you have to use a 25 – 0 – 25 @ 2.5amps transformer. Q1 & Q2 you may use only BC107 or 547 not BC108(some samples may fail).

  • David says:

    Dear sitharaman

    i have used BU407 instead of 2N6107
    For R2&R5 i have used 560 ohms instead of 680
    For R4 – 4.1K instead of 4.7K
    For R7,R9,R10 18ohms instead of 22ohms
    For R11 1.8k instead of 1.5K
    For R13&15 120ohms instead of 100ohms
    For R16&R14 i have used 0.5ohms instead of 0.33

    all these are changed due to lack of availability

    Please Help me it is not working to me
    i have checked many times but no use

  • David says:

    Dear sitharaman

    i have center tap transformer but when i connect to +35 -35 and ground its getting shorted my fuse burnt out

    i have seen the circuit diagram of 40v in this site done as it is but it happens as stated above

    what i have to do now please tell me .
    is this ciruit is correct?

  • seetharaman says:

    Hi David You require a total of 70 volts DC with centre tap. Hence with reference to Zero (common) you should have both positive 35 and negative 35 volts. like operational amplifier plus minus 15 volts.

  • David says:

    Dear sitharaman what is +35 and -35 can i combind those please tell me

  • Benzman says:

    Hi seetharaman
    could you please give me the circuit diagram of active sub woofer filter my mail address comasus@gmail.com

  • seetharaman says:

    Hi Nirmal you have to use a pre amplifier since the amplifier requires around 400mV RMS input for the rated output.
    If you want to use this as an exclusive sub woofer amplifier increase C1 to 4.7uF and use an active sub woofer filter before the amplifier

  • seetharaman says:

    Hi Shreya since he is going to use 15 ohms speaker 1.5amp is sufficient for 8 ohms load you require 3amps rating. you can comfortably use 5amps transformer.

  • nirmal says:

    hai is there is any pre amplifier need for this circuit

  • shreya says:

    Hi Seetharaman

    So i can use 35-0-35 5 Amperes Transformer by changing Q1 and Q2 with MPSA43 Right?

    But you stated to Joel dated July 7 1.5 A

    can i use 5A for single amplifier

  • seetharaman says:

    Hi Shreyas upto 200watts you dont require to use any parellel transistors.
    any way to parellel out put trasistors connect both bases together connect both collectors together. but for emitter for each transistor use a seperate 0.33 ohms resistance. this will protect the transistors from thermal runaway.

  • seetharaman says:

    Hi Shreya This amplifier is a general pupose amplifier. To make it into a sub woofer amplifier you have to use the sub woofer filter. If you want to use it as a general purpose amplifier increase C1 to 5uF and reduce C5 to 47 to 100PF.
    35 – 0 – 35 transformer will give you a no load voltage of 35 X sqr 2 = 50 volts. It will be quite high, you refer to my reply to mr.joe dated 6th july for the required modifications.

  • shreya says:

    Hi Seetharaman

    is this amplifier can be used for speakers
    what changes have to be made can you tell me please

    and also how can we add two more transistors along with same model of Q4 and Q7 to share the load

    can you suggest me the transformer like how much amperes should i use

    i have ’35-0-35 5A Transformer’ can i use this for the present shown circuit
    please tell me

  • seetharaman says:

    Hi Joel Higher the load impedance – higher voltage, less current to get the same power. A 1.5 Amp transformer will do for a single amplifier.

  • Joel says:

    Thankyou Seetharaman

    So i have to increase only supply voltage.

    Then what about current 5A is enough???

  • shreya says:

    Hai SEETHARAMAN

    i want to use this as normal amplifier not as subwoofer amplifier so what changes have to be made

    and also want to add two more transistors to Q7 and Q5 with same model to share the load

    i don’t know how to do it can you please tell me

  • seetharaman says:

    Hi Joel you can use higher than the rated impedance speakers with any amplifier, only thing is the available power will get reduced. In this circuit it will get reduced to 45 to 50 watts. To increase you have to increase the supply voltage to plus minus 55 volt and replace Q1 and Q2 with MPSA43. use all capacitors with 63 volt or higher rating

  • joel says:

    i want output load to 16ohms can any body tell want changes have to do to this circuit

  • kvs says:

    k. i want that time delay line circuit. the above attachment will not open.

  • seetharaman says:

    Hi KVS you can use a direct signal mix with delay signal and use a single amplifier. but to avoid inter modulation and distortion problems I always use a spare amp for delay line. the delay line is required to give the reverbration of a big hall. so your existing room will look like enlarged into a big hall or auditorium. this is called commercially as echo effect. there are bucket brigade chips available for different time delay line.
    http://www.diyaudio.com/forums/attachments/solid-state/44028d1115536209-echo-reverb-using-bucket-brigade-delay-lines-panasonic-bbdl.jpg

  • kvs says:

    hi seetharaman can you explain me that above?

  • kvs says:

    so i create another circuit to another woofer for theatre effect? what can i do for a small time delay circuit in the second 100 watts amplifier with woofer? please send that time delay circuit to me. my mail id http://www.senthilkvs88@yahoo.com

  • seetharaman says:

    Hi KVS It will reproduce heart thumping beat. But for theatre effect you require a small time delay circuit in the second 100 watts amplifier with woofer.

  • kvs says:

    is this circuit produce theatre effect? that i mean heart beat thumping? with 8inch,100w,rubber woofer? in 15*15feet room. please send reply for me mr.seetharaman.

  • seetharaman says:

    Hi Gouranga you have to use center tap transformer and a bridge rectifier with minimum 4700uf capacitor in both positive and negative power supply
    By increasing C1 to 4.7uf you can achieve response down to 20Hz.

  • GOURANGA says:

    how mach frequency this amplifier respond?
    is there need bridge rectifier in power supply?
    or how connect the power supply in to the amplifier?

  • seetharaman says:

    Hi Nayak
    All Capacitors to be of 50 volts rating. This amplifier as such can respond to voice also may be upto 6KHz it can respond. Hence you have to neceesasorily use the sub woofer filter to take care of it. Increase C1 value to 2.2 to 4.7uF.

  • what is the voltage of all capacitors. also any one tell me that the amp. outs only bass. no voice. or outs voice also?

  • seetharaman says:

    Hi Chris The second wire should get connected to the 0 volt of +35 & -35Volt. similarly the input side ground also should get connected to 0 volt of the power supply. the input socket common also should get connected to 0 volt of the power supply and to the metal chassis as close to the input socket as possible. (power supply o volt should not get grounded anywhere else except near the input socket as indicated). If your home theatre has got subwoofer output connect it to this amplifier. To get 100watts output use 12″ 4 ohms impedance speaker, front mounted in 20mm thick wooden cabinet of inner volume not less than 35litres.

  • Chris says:

    hi, I am planing on building this circuit to go along with my old home theater system. can you post or send me a parts list of all the components I will need and some tips on building it.
    I also see that the speaker has only one wire going to it. where is the second wire? If it is a ground wire, do i connect both ground wires together, then ground it?

  • seetharaman says:

    Hi Allan low frequencies are not heard, but felt by our body. in my experience a clean 100watts (as per DIN45500) of bass is more than sufficient to be felt in a room of 3000 cub ft.

  • allan says:

    sir, why does our output is so small that we can only hear a sound about 40hz? how can we make our output sounds better?

  • seetharaman says:

    Hi this amplifier is designed as a sub woofer amplifier to cover low frequecies only, you have to use this after the sub woofer filter. but can be modified easily as a full rane amplifier also.
    you can use a 100Kohm potentiometer in the input. slider connected to C1 and cold end of the pot to common, input signal between hot end(other end of the pot) and cold end of potentiometer. increase C1 to 2.2 or 4.7uf non electrolytic capacitor to improve low frequency response to 10Hz or so, with the present value the roll of will be above 50Hz itself.

  • Chris says:

    Is there a volume Control?
    Is the diagram of the circuit in the picture a design to work as a subwoofer (120 hz and below),or is it designed to cover all frequencies( about 80 hz-20,000 hz)

  • seetharaman says:

    Hello Gannex this is the best tone control circuit. you can add it before the sub woofer amplifier at C1 (‘in’ signal)with its own power supply as it uses only a single supply. reduce C5 between 47 to 100PF, if you want to use this amplifier as an independant hi-fi installation, not as sub woofer amplifier.

  • GANNEX says:

    Hello Seetharaman, thank you for your advise.
    I found this tone control at http://www.aaroncake.net/circuits/tone.asp and i want to integrate this in the circuit. Where should i connect the input and output of the tone control? Is it in series between the output of Q1 to the input of Q3 (not Q2 sorry)? Or just to place the tone control before the input of the 100W Subwoofer Amplifier? Thanks you.

  • GANNEX says:

    Hello Seetharaman, thank you for your advise.
    I found this tone control at http://www.aaroncake.net/circuits/tone.asp and i want to integrate this in the circuit. Where should i connect the input and output of the tone control? Is it in series between the output of Q1 to the input of Q2? Or just to place the tone control before the input of the 100W Subwoofer Amplifier? Thanks you.

  • seetharaman says:

    Hi connect a tone control network before the main amplifier with its own power supply. you can use a simple passive tone control and add a transistor amplifier with a voltage gain of 50. if you want to use the same power supply use suitable regulators and tone control circuit with dual supply. these circuits are availabe on the net

  • Gannex says:

    Hello Guys!
    I just would like to know if is it possible to add Bass & Treble control in the circuit, perhaps using a potentiometer? How and where to place the controls? Thank you very much.

  • seetharaman says:

    Hi Anthony Deane are you supplying both +30 and -30 volt(total supply voltage is 60volts). if so it should work. The groud indicates that it should be connected to zero volt reference. Q3, Q4 & Q6 require a small cooling fin each. For Q5 & Q7 use a good quality extruded alloy heatsink insulate them using available ready made kits.

  • Ace says:

    hi,
    Is this circuit is for subwoofer only?what i mean is,is output only low frequency no high frequency coming out?i want to build this circuit,is there any one can guide me,
    thanks,

  • Anthony Deane says:

    Hi Guys,
    I Build the 100w subwoofer circuit and power it with 24v 4amp transformer, which when rectifies gives an output voltage of 30v dc. My problem is when i test the circuit with this 30v, it send an output signal to the speaker and then stop.
    I then test back all the components on this circuit which test o.k, but i am not geting back the signal to the speaker.what advice can you give me, one more thing how to layout the output transistors do all them have to moumt on the same heat sink insulated properly.

  • Anthony Deane says:

    Can You please send me the power supply diagram for the 100w Subwoofer project.

  • seetharaman says:

    Hi Suku you can use a 100Kohm potentiometer in the input, slider to C1 cold end to common, between hot end and cold end of potetiometer input signal. Except C5 no other feed back or filters are used. this can give a good frequecy response upto approx 8KHz beyond 10KHz it will be rolled of. For a hi-fi application you can reduce this to 47PF add 1Kilo ohms with 470PF input filter to amplifier. increase C1 to 2.2 or 4.7 micro farades poly carbonate capacitor.

  • SUKU says:

    Hi
    Can you tell me what is the range of frequency response and any way to control the output like using pot or so

  • elango says:

    hello admin,
    To obtain +35v&-35v,which type of voltage rating step down transformer can we use?

  • Seetharaman says:

    Dear Ram Iam using this amplifier as an Hi-Fi amplifier at home. Hence the suggested improvements. To use as a sub woofer amplifier for which it is designed leave C5 as it is. increase C1 to 2.2mfd poly corbonate capacitor. with 8 inch venyl rubber surround woofer in 25 litre infinite baffle gives eccelent thumping bass reproduction. assemble and listen to believe it.

  • Seetharaman says:

    Yes Mr Ram
    This simple amplifier is really sounding very good you need not have any doubt about it. If you use good practice in laying out the components the given circuit will work very well. You may require small improvement depends on your layout. You can provide input filter with 1kohm resistance in series with the input and by passing it with 470pf to common. This will limit the amplifier responding to frquncies beyond audible range (simple low pass filter) You can connect 100mfd electrolytic in parallel with 0.1 mfd ceramic capacitor to positive and negative supply rail close to power transistors for power supply decoupling due to long inter connecting wires if used. After these modifications If you feel high frequency response is little lesser reduce C5 to 100 to 150PF. wishing you happy listening.

  • Ram says:

    is this cricuit working????????????
    or any correction is requried

  • Ram says:

    is that 10k (R8) is include….
    is that connected to base of Q4..

  • rajeev says:

    realy fentastic site this one, very very thanks to you ……
    so many new ideas from here. thank you…

  • twits4twats says:

    Is this Circuit Working ?

    Nilesh

    The circuit looks like it will work allthough I haven’t built it myself. This uses a high pass filter and a class A amplifier. Active filters are a better solution and the only resistors that require a higher wattage rating are R16 & R14.

  • mukba says:

    hi buddies….mukba from georgia
    amplifier is excellent,great
    if u have any questions you can ask me

  • ian cabajar says:

    can we use an 8 ohms speaker for this amp.?

  • ian cabajar says:

    what is the voltage of all the capacitors? electrolytic and ceramic

  • nilesh says:

    Is this Circuit Working ?

  • shyam says:

    how do you connect the heat sinks to Q4 and Q7 and why heat sinks are required here??

  • Adam says:

    IS there anything else that can power this circut other than 35v.

  • kiran says:

    hi i have made this circuit i am having some kind of hum sound in this i need to know wats the problem in the circuit and should i use mica for output transitors to the heat sink can u pls guide me

  • ganesan says:

    I have 35 0 35 secondary transformer and the rectified output shows around +47 0 -47..

    Is it suitable to connect for this circuit.

    • YED KRiz says:

      NO IT WILL DESTROY ALL OF UR COMPONENTS IN THE CIRCUIT….
      USE 25/0/25 VOLT RMC AC @ 3 AMPS,THIS WILL PRODUCE +36/0/-36 volts DC best suited for this amplifier.

  • jery says:

    wat type of capacitors are c2&c3 resistors whose wattage are not specified must be 1/4 watts is’nt it

  • pwill says:

    c1 is what type of capacitor

  • neto oliveira says:

    gosto muito de projecto amplifier e outros

    fortaleza brasil

  • Tende ivo says:

    I must say I’m very proud of this site but i will be very glad to hear you say whether the circuit needs a power transistor or not
    and how it is connected.
    I am waiting to hear from you people.
    Thanks

    • admin says:

      the transistors used in the final stage are power transistors itself.

      • jonas says:

        sir, pls send a complete layout of your 100w sub-woofer amplifier. i am very interested to make and assemble this circuit.thks & happy new year.

      • JayCee says:

        g’eve sir, .,if you have time plsss send me the pcb layout of this design!, .,thanks much!

        • SEBIN JACOB says:

          seetharaman sir,

          I want a stereo amplifier circuit.The 150 w amplifier using tip147 in your site and this circuit, which will work fine which one gives the good sound clarity and good output please help me.I am already using this circuit as a sub woofer amplifier it works good.if i want to double this for stereo amplifier how much amp transformer i must use is 5 ampere enough.