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.
Show Comments

773 thoughts on “100 Watt sub woofer amplifier.

  1. Gautham

    Hi i want to know,,,, is this possible
    Normal stereo amplifier to subwoofer amplifier
    Convert -> Normal -> Sub ?????????

    Reply
  2. SEBIN JACOB

    Dear Seetharaman Sir,

    i am using this circuit as a subwoofer amplifier for past 3 years…working fine..but when i am using it as an amplifier with out any subwoofer filter then the 2m3773 is getting hotter when it is worked at its full volume.Plse help me to rectifiy this because i love this amplifier it sounds good and simple to make

    Reply
  3. SEBIN JACOB

    Dear Seetharaman Sir,

    I was using this amplifier for past 3 years i checked my amplifire recently and i found the resistor R13 100R 2W is blown. it is not actually blown but it is burst out.i replaced with a new one and i found that while working the R13 is getting very hot but the amplifier is working properly. please help me to resolve this problem sir.

    Reply
  4. Prajyot

    hello,
    I have a pair of car Speaker with old magnetic car tape And also have a 12v power eliminator to connect at home but this is old fashion.

    Now i want to make a circuit that connect to my mobile to play the music.
    Using these sound and 12v power suppyer.

    So please help me to make it working.
    Also want to know what components should be required to make a circuit.

    Please help me.

    Reply
  5. markson 5.1 ch front displ pcb

    Sir i need remore control 5.1 chanal with display .(clk.dat .5v .acb and ic 07bana005e3 i have caicuit but dont no correct ic no

    Reply
  6. harith

    sir..i made this circuit…i designed the PCB and buld it…but it works in best way for 3 mins and then lower the sound and produce a humming sound with varying bass sound… one 3773 transister is heating up… i cant understand why it is happening… can any one help me….

    Reply
    • anil babbar

      please check Q5 & Q6 , and re-solder all the connections ( to rule out any dry solder- its a common problem with etched pcb)
      also check the pcb it must be an etched pcb sometimes it is not able to carry the current the best way( for the hobbyist) is to solder a copper wire all along the pcb connections
      finally the Q 7 is bound to heat up and iff u mount Q6 also on the same sink it will also get heated. USE A GOOD QUALITY HEAVY HEAT SINK OF NOT LESS THAN 8″ x 4″ WITH GOOD FINS

      Reply
  7. anil babbar

    sir I want to add a filter circuit to this amplifier which requires a separate power supply of +12 / -12 VDC, can you give me a power supply circuit that can supply +/- 12 VDC and +/- 35 VDC from a single transformer
    thanks

    Reply
  8. Ateeq

    my question is that i can not get the transistor 2n3773 because in the circuit diagram you have shown three legs of that transistor but in market it has only two legs.could you please tell me the substitution of that transistor or please guide me because i have to submit my final project in two weeks. please help me……….

    Reply
  9. Riyaz

    Sir how can i convert 12 -0 -12 suly to 25-0-25 with a transistor power suply please give me diagram

    Reply
  10. john

    hi sir which is the best for subwoofer amp. this circuit or 150 watt amp circuit.???? i want to make subwoofer amp.

    Reply
  11. vinnie

    Hello sir,can i use 12v input to the amplifier? if yes pliiz provide the circuit containing 12v input signal.
    another request sir…please send me the dual 35+/35- power supply circuit of the amplifier.

    Reply
  12. john

    Hi sir! is this ckt need separate transformer? or can i use tip 142 and 147 150 watt ckt’s powersuply. if i connect like that, is this both amps output transistors will short?

    Reply
    • Seetharaman

      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.

      Reply
  13. Rituraz

    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 .

    Reply
  14. abubakar

    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

    Reply
  15. Chris

    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!

    Reply
  16. abubakar

    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

    Reply
  17. babu

    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.

    Reply
    • Seetharaman

      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.

      Reply
  18. abubakar

    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

    Reply
  19. harith

    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.

    Reply
  20. IH55T

    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.

    Reply
  21. krishna

    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.

    Reply
  22. sravan

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

    Reply
  23. RAVI

    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.

    Reply
    • siva.R

      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.

      Reply
  24. cooool

    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

    Reply
  25. Harry Cat

    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

    Reply
  26. vitthal

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

    Reply
  27. Janaka

    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..

    Reply
    • Seetharaman

      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

      Reply
  28. ASHISH KUMAR

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

    Reply
  29. Janaka

    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..

    Reply
  30. Janaka

    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.?

    Reply
    • Seetharaman

      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.

      Reply
      • rohin

        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.

        Reply
      • rohin

        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.

        Reply
      • Seetharaman

        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.

        Reply
  31. Petar

    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.

    Reply
  32. Ch.shashank

    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…….

    Reply
  33. srinivasan

    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

    Reply
    • sino

      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 .

      Reply
  34. migs

    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..

    Reply
  35. manish

    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

    Reply
    • Janaka

      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.

      Reply
  36. manish

    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……

    Reply
  37. omer

    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 ?

    Reply
  38. Kennedy Marquez

    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.

    Reply
  39. pradipta pal

    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.

    Reply
    • rohin

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

      Reply
  40. YED KRiz

    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

    Reply
    • rohin

      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

      Reply
    • seetharaman

      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.

      Reply
    • rohin

      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.

      Reply
  41. sai ram

    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

    Reply
  42. PRAMOD MANUJA

    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.

    Reply
  43. omer

    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.

    Reply
    • seetharaman

      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.

      Reply
  44. omer

    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.

    Reply
  45. PRAMOD MANUJA

    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 ?

    Reply
  46. sai ram

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

    Reply
    • Seetharaman

      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.

      Reply
  47. Punam Pradhan

    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

    Reply
  48. rohin

    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.

    Reply
  49. ishan1211

    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?

    Reply
  50. sebin jacob

    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

    Reply
  51. NASA

    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…..

    Reply
  52. Pankaj

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

    Reply
  53. Seetharaman

    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.

    Reply
  54. kanagaraj.s BE

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

    Reply
  55. Pankaj

    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??????

    Reply
  56. Seetharaman

    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.

    Reply
  57. Pankaj

    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…..

    Reply
  58. Pankaj

    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

    Reply
  59. jocel

    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

    Reply
  60. P.Srinivasan

    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 ?

    Reply
  61. bal wolley

    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?

    Reply
  62. seetharaman

    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.

    Reply
  63. P.Srinivasan

    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 ?

    Reply
  64. Sujeesh

    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

    Reply
  65. seetharaman

    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/-

    Reply
  66. P.Srinivasan

    Dear seetharaman sir,

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

    Reply
  67. Seetharaman

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

    Reply
  68. Ajith

    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.,

    Reply
  69. rohin

    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.

    Reply
  70. P.Srinivasan

    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.

    Reply
  71. harshit

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

    Reply
  72. rohin

    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.

    Reply
  73. kutty

    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????

    Reply
  74. Seetharaman

    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.

    Reply
  75. Ajith

    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.,.

    Reply
  76. rohin

    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

    Reply
  77. ajay

    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.

    Reply
  78. ajith

    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…..

    Reply
  79. rohin

    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

    Reply
  80. rohin

    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.

    Reply
  81. seetharaman

    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.

    Reply
  82. ajay

    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..

    Reply
  83. Seetharaman

    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

    Reply
  84. seetharaman

    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.

    Reply
  85. P.Srinivasan

    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

    Reply
  86. rohin

    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

    Reply
  87. P.Srinivasan

    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

    Reply
  88. J S Nagaraj

    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.

    Reply
  89. J S Nagaraj

    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.

    Reply

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