150 Watt Amplifier Circuit – DIY Guide to Build Amplifier

admin August 11, 2018 1,104 Comments

Low Cost 150 Watt Amplifier Circuit

In this project, we’re building a simple 150 watt amplifier circuit.


This is the cheapest 150 Watt amplifier circuit you can make,I think.Based on two Darlington power transistors TIP 142 and TIP 147 ,this circuit can deliver a blasting 150 W Rms to a 4 Ohm speaker.Enough for you to get rocked?;then try out this.

TIP 147 and 142 are complementary Darlington pair transistors which can handle 5 A current and 100V ,famous for their ruggedness. Here two BC 558 transistors Q5 and Q4 are wired as pre amplifier and TIP 142 ,TIP 147 together with TIP41  (Q1,Q2,Q3) is used for driving the speaker.This circuit is designed so rugged that this can be assembled even on a perf board or even by pin to pin soldering.The circuit can be powered from a +/-45V, 5A  dual power supply.You must try this circuit.Its working great!

The preamplifier section of this circuit is based around Q4 and Q5 which forms a differential amplifier. The use of a differential amplifier in the input stage reduces noise and also provides a means for applying negative feedback. Thus overall performance of the amplifier is improved. Input signal is applied to the base of Q5 through the DC decoupling capacitor C2. Feedback voltage is applied to the base of Q4 from the junction of 0.33 ohm resistors through the 22K resistor. A complementary Class AB push-pull stage is built around the transistors Q1 and Q2 for driving the loud speaker. Diodes D1 and D2 biases the complementary pair and ensures Class AB operation. Transistor Q3 drives the push-pull pair and its base is directly coupled to the collector of Q5.

Circuit Diagram & Parts List .

150 watt amplifier

150 watt amplifier circuit diagram

PCB’s for this project can be ordered through PCBWay. We shall upload a sample PCB file (for download) shortly.


  • Remember TIP 142 and 147 are Darlington pairs  .They are shown as conventional transistors in figure for ease.So don’t get confused.Even though each of them have 2 transistors ,2 resistors and 1 diode inside ,only three pins ,base emitter and collector are coming out.Rest are connected internally.So its quite OK to assume each of them as transistor for ease.
  • Use a well regulated and filtered power supply.
  • Connect a 10K POT in series with the input as volume control if you need.Not shown in circuit diagram.
  • All electrolytic capacitors must be rated at least 50volts.

Power supply for this circuit.

A  +40/-40 unregulated dual supply for powering this amplifier project is shown below.  This power supply is only enough for powering one channel and for stereo applications double the current ratings of  the transformer, diodes and fuses.

amp supply

Power supply for this project

TIP 142 & 147 Internal diagram and pin out.

TIP 142-TIP 147 Pin Out Diagram and Schematics

TIP 142-TIP 147 Pin Out Diagram with Schematics

Note:- We have explained how to create a schematic of this circuit and its PCB using an online EDA tool – EasyEDA.  You may read the article to understand how to draw and develop a PCB of this circuit.

We have more related list of  Amplifier Circuits that you may like to visit;

1. 2 X 60 Watts Stereo Amplifier Circuitis designed using LM4780, an audio amplifier IC that can deliver 60 Watt RMS output power per channel to  8 Ohms speakers.  Advantages of using this IC are low harmonic distortion compared to other IC amplifiers of similar category and a power supply rejection rate of 85db. In addition it require minimum components and a built in mute function.

2. Headphone Amplifier CircuitThis is a simple circuit which uses only 3 transistors, that can be used to drive your headphone. It can be easily built by any one and can be powered using a 3 volts battery.

3. Mosfet Amplifier Circuit This circuit is designed using two Mosfet’s and one transistor; which makes it an easy to build circuit. It can deliver 18 Watts output power to 8 ohms speaker or 30 watts to 4 ohms speaker; you can do it the way you like it. Another advantage of this circuit is the minimal use of components.

4. 40 Watts Amplifier using TDA1514 TDA1514 is a high performance hi – fi amplifier from Philips. It requires a dual +25/-25 volts supply. Advantages of using TDA1514 are low THD, mute standby feature, thermal protection and other features. It can deliver 40 watts of output power to an 8 ohm speaker. You need a proper heat sink for the desired reliability of this circuit.

5. 2 X 32 Watts Stereo Amplifier CircuitThis circuit is built using TDA2050 which is a 32 Watts Class AB Audio amplifier IC (monolithic) . This IC has many features like thermal shut down, low THD, short circuit protection etc. This circuit uses Two of these IC TDA205o; one for each channel.  An 18 volts dual power supply is required to power this circuit.

  • September 30, 2018

    Hello sir. I need your help because i have a problem with the output sound. when the volume level is max the output sound will distort or noise. my transformer is 15 0 15 6ampere. i Hope for your reply sir

  • joseph
    September 30, 2018

    Hello sir i have a concern with the output because when the volume is in the maximum level it will distort or creates noise. I use 15-0-15V and 6ampere transformer. please help me sir.

  • sijesh tp
    July 5, 2018

    tip 41 – replace tlp 142 instead

  • Nirmal Joseph
    June 29, 2018

    Please tell be the minimum and the maximum volage range of this circuit.

  • May 3, 2018

    Can anyone please help..When i pluged in supply voltage to the circuit Tip 142&147 got burnt…My supply output voltages are +-47 and 3.5 A… Can anyone plz tell me what i have done wrong…

  • Sajad
    March 23, 2018

    Hello sir
    What type of transistors can i use except tip’s??

  • Gopinath G
    January 19, 2018

    Hello Sir,
    With pleasure may I tell that the circuit diagram of 150 watt amplifier is very good to read. The “Stereo Amp” will be identical with “Mono Amp” circuit. Anyway before the assembling, powering and connecting the exact specified load to the system,the sound quality will tell me pleasant and nice. Sir instead of publishing only the circuit diagram,kindly provide the stereo amplifier PCB, the power supply board along with the transformer specifications say the data for winding with gauge of the insulated copper wire for primary number of turns as well as for secondary reminding of ampere, the core size and lamination’s brand etc. Sir I am very much interested in assembling of stereo sound systems with high output in RMS ratio. If you provide me here above items,very frankly indicate, I don”t mind about the cost at all.

  • Ron Thomas
    May 11, 2017

    I am not real knowledgeable on SS…I do have an Ampeg B3158 bass guitar combo. This amp uses TIP 142 and 147’s in it’s power output circuit.
    My question is can these pwr transistors develop lower output volume but still function or they like a diode….it works or doesn’t?
    I ask because when I first got the amp I didn’t have to turn the gain and master up as much as I do lately.
    Just curious and thanks for your time to whoever replies to straighten me out on this……
    Ron Thomas

  • Muhammad Usman
    April 9, 2017

    What is F1…?

  • March 3, 2017

    Sir I’ve built this amp but I’m hearing a loud hum. Is this maybe I should have a good earth to the circuit? Thanks

  • Pablo D
    December 13, 2016

    You can replace tip142 with 2SD718 and tip147 with 2SB688. If yes, is tip41 left unchanged or replaced?

  • Nibin Joseph Kochi
    November 1, 2016

    I want to make 5.1channel150 watt amplifier. post more information about that, and plz upload the amplifier circuit diagrams of speakers and sub woofer.

  • kees kwakman
    August 27, 2016

    works perfect on breadboard for me 🙂

  • mukesh kamble
    August 22, 2016

    can i use 10” 80watt subwoofer for this amplifire .

  • Hi there to every single one, it’s genuinely a good for me
    to visit this web site, it consists of useful Information.

  • April 12, 2016

    Sir I have made that circuit on vero board.All continuity and connections are double checked found OK.But when I give signal input from PC or mobile no audio output is available at speaker.Please help me and guide me sir what should I do.Im using 24-0-24 Transformer and instead to Diodes Bridge combination I am using a Packed Bridge rectifier.Dc out put is ±30.Please please please help me and guide me sir.

  • S.NAND
    March 24, 2016

    SeetaRaman Sir,
    what a fentastic circuit, this 150 W audio ampli circuit of darlington pair transistors Tip
    142 n Tip 147.Boundles of output power.I check the sound quality of this amp. is excellent.
    i use 12 v auto head lite bulb(upper-dipper both filaments) instead of 0.33ohms/7w resistances.
    Sir plz sugest me a suitable bass/treble or 3 band graphic equaliser cir.diagrm for this
    power amp.

  • Jarrod Houle
    February 18, 2016

    i know this is a little old. how will this perform as a guitar amplifier? im assuming this will work fine but is there anything i should know?

    • Mirza Salman
      April 30, 2016

      This circuit doesn’t work properly…. It has a lot of distortion in output further more the output sound is not more than 10 watt rms…
      Noise is removed by replacing 220ohms resistor with 550 ohms resistor. It will adjust the gain of amplifier so noise will be removed.

    • May 22, 2016

      i make this circuit and i buy all components but if i already built this 150wRMS Amp nothing SOUND i hear .

    • Bruno Bonvini
      December 21, 2016

      You can use this amplifier as a guitar amplifier because is a class AB. It means there are a pre-amplifier in the circuit. I hope have answered your question.

  • November 7, 2015

    It’s actually a great and useful piece of
    info. I am satisfied that you just shared this helpful information with us.
    Please stay us up to date like this. Thank you for sharing.

  • July 5, 2015

    can you please tell me about its major applications?

  • fernando
    June 1, 2015

    I build this and it sounds good. but when i increasing volume, R10 become very hot and get burned. please help sir.

  • […] TIP142 / TIP147 Darlington güç transistörleri kullanarak inşa etmek ucuz 150W ses yükseltici […]

  • Rex
    April 9, 2015

    Seetharaman, the 7watt 0.33 ohm resistor and the 1watt 3.3k resistor, are they carbon film resistor or wire wound resistor

    • emmanuel
      March 16, 2016

      they are both wire wound resistor u see watt where added to it

    • Mirza Salman
      April 30, 2016

      Wire wound

  • Rex
    April 9, 2015

    Seetharaman please send me the 7watt resistor O.33 ohn and 1 watt 3.3k resistor image and details to my gmail. Rextech02@gmail.com

  • Rex
    April 4, 2015

    Seetharaman, can i use 1N4148 doide instead of 1N4007 Diode for the Amp circuit

  • Rex
    April 4, 2015

    Seetharaman, can i use 1N4148 instead of 4007

    • Bruno Bonvini
      December 21, 2016

      No, you can´t. 1N4007 is 1A, 1N4148 is 200mA high speed diode.

      Philips Semiconductors Product specification
      High-speed diodes 1N4148; 1N4448
      • Hermetically sealed leaded glass
      SOD27 (DO-35) package
      • High switching speed: max. 4 ns
      • General application
      • Continuous reverse voltage:
      max. 75 V
      • Repetitive peak reverse voltage:
      max. 75 V
      • Repetitive peak forward current:
      max. 450 mA.
      • High-speed switching.
      The 1N4148 and 1N4448 are high-speed switching diodes fabricated in planar
      technology, and encapsulated in hermetically sealed leaded glass SOD27
      (DO-35) packages.
      Fig.1 Simplified outline (SOD27; DO-35) and symbol.
      The diodes are type branded.
      handbook, halfpage
      k a
      In accordance with the Absolute Maximum Rating System (IEC 134).
      1. Device mounted on an FR4 printed circuit-board; lead length 10 mm.
      VRRM repetitive peak reverse voltage − 75 V
      VR continuous reverse voltage − 75 V
      IF continuous forward current see Fig.2; note 1 − 200 mA
      IFRM repetitive peak forward current − 450 mA
      IFSM non-repetitive peak forward current square wave; Tj = 25 °C prior to
      surge; see Fig.4
      t=1 µs − 4 A
      t = 1 ms − 1 A
      t=1s − 0.5 A
      Ptot total power dissipation Tamb = 25 °C; note 1 − 500 mW
      Tstg storage temperature −65 +200 °C
      Tj junction temperature − 200 °C

  • edward
    March 31, 2015

    Is it advantageous to use a constant current source instead of R6? The aim is to emulate an infinite impedance theoretically increasing the common mode rejection ratio to infinity?

    To avoid using positive feedback in the output stage is it beneficial to add two more transistors connected in such a way that the Darlington’s would be made of three cascaded transistors instead of the usual two.

    I did some reseach and what I learnt so far corroborates my impression that this circuit is well designed and worthy of a try.

    Thanks for taking the patience to reply.

  • edward
    March 28, 2015

    I am interested in building this amplifier but am finding difficulty accepting the differential input should be driven between -45V and +45V. I also think, using PNP transistors for a differential input is quite uncommon today.

    1) To meet my criteria I changed parts of the circuit so that the differential input is made of NPN transistors instead that are connected between 0V (common, ground) and the +45V.
    2) The output stage has also been modified so that R3 and R5 are on the negative side of the supply (-45V). I moved the driver transistor Q3 to the other side, that is, the +45V making sure to keep the same resistor values. Naturally, Q3 has been replaced by a PNP transistor.
    3) In the input stage, differential input, the signal ground has been made the same as that of the differential input stage.

    I am attempting to build the amplifier with my modifications.

  • sathvik
    March 17, 2015

    sir what other component can you use in place of TIP147 and TIP142 and please sent me the pcb of the project

  • ravichandran
    February 1, 2015

    I have the amplifier board using transistors TIP143andTIP147 by using
    transformer is 28-0-28,10A dual power supply.My problem is switch on the power supply ,I heard the sound on the speaker is like feedback between the mic and speaker….woooooooo….so you help to rectify the problem

    • Mirza Salman
      April 30, 2016

      Noise is removed by replacing 220ohms resistor with 550 ohms resistor. It will adjust the gain of amplifier so noise will be removed.

  • January 25, 2015

    sir please sent me the pcb of the project and how make pcb from jpg format

  • grigo
    January 24, 2015

    i finished this amplifier and the sound seems very clear but very low comparing to a 100w …i get like 8 or 10w at max ….for a speaker of 80w 8ohm i used a supply of +-45 5A and 2 of 0.22ohms 5w and a pairs of MN2488 MP1620 instead of the tip142/147 and for the rest i used the same as the shema and no picofards for modifications … any suggestions plizzz ?

  • Jefferson Barrion
    January 12, 2015

    Hey guys have you already tried the PCB design of this schematic by jspayne? but there are just some modifications recommended to improve the amplifier’s performance, i think it is good. you can search it in google.

  • Mongo David
    December 26, 2014

    what other component can you use in place of TIP147 and TIP142

  • aiza basquina
    December 18, 2014

    Try this 300W Hi-Fi mosfet Amplifier http://adf.ly/vNFeo. The sound is superb.

  • Aiza Basquina
    December 18, 2014

    http://adf.ly/vLIxB link of 100 watt subwoofer amplifier PCB layout comes from Sir Seetharaman. Install Pad toPad software to open PCB file. Thank you sir for the PCB layout God Bless.

  • sebin jacob
    November 18, 2014

    for stereo can i double this circuit and use a 5A transformer is it enough.

  • Pascual
    November 17, 2014

    Dear Seetharaman Sir
    If i use 2SD2390/ 2SB1560 can i power this from 56-0-56V and what will be the output power? Using TIP142/ TIP147 and power it from 56-0-56V all of the sudden the emitter and collector of output transistor got shorted.

  • sebin jacob
    November 17, 2014

    Dear Seetharaman sir,

    can i power this 150w amplifier from a 25-0-25 transformer.how much watts will be the output if i charge it from 25-0-25 8ohm speaker.
    please find the link below, will it works and give 400w output.which is the better circuit 150w circuit in this page or the circuit in the link bellow.please help me to choose one.


    • Andrew B
      November 25, 2014

      Sebin I’m powering mine with only 11-0-11 8ohm speaker.
      If you give 45-0-45 it gives 150w.
      For 400w you need another circuit.

  • abraham
    November 13, 2014

    Hi is -45V 0 +45V 3A is enough to supply for stereo? Thank you.

  • Michelle Teoh
    November 10, 2014

    sir, can I have your pcb diagram for this circuit? Thank you very much.

  • Andrew Borg
    November 9, 2014

    Sir I’ve built this amp but I’m hearing a loud hum. Is this maybe I should have a good earth to the circuit? Thanks

    • Andrew Borg
      November 21, 2014

      I’m using 4700uf caps as shown in schematic. In one of the comments Seetharaman you said 10000uf for filter!! are these the right caps so?

      • November 25, 2014

        Problem solved. Added more capacitors to 9000uf.

    • Mirza Salman
      April 30, 2016

      Noise is removed by replacing 220ohms resistor with 550 ohms resistor. It will adjust the gain of amplifier so noise will be removed.

  • November 7, 2014

    Sir can i use tip3055 insted of tip147 and tip2955 insted of tip 142. Please,

  • November 5, 2014

    am working presently on this amplifier.. But i couldnt get tip147 could u pls tell me which i can use as a replacemant, and also the 30 0 30v transformer is expensive here, is there anyway i can use the cheaper one… And again the 10k potientiometer how do i connect it to the circuit

    • AB
      November 22, 2014

      Chris if you read past comments there are others who found alternative transistors and regaring volume pot is said to put it in series with input

  • abraham
    October 31, 2014

    It is okay to supply 56-0-56V in this circuit?

    • Mirza Salman
      April 30, 2016

      You must replace bc558 transistors before using this supply. Because! Maximum voltage that bc558 can bear is 60v so search for high voltage transistors in place of bc558…. Hope this solved your quest… ☺

  • Almighty'kingdavid
    October 30, 2014

    i will like to study this oversea

  • October 10, 2014

    Please can anyone help me with this problem; whenever i connect the power supply to the audio amplifier circuit, the +40V and -40V voltage lines always get burnt. This has been recurring

    • Andrew B
      November 25, 2014

      Matti003 it seems that you have a short somewhere if the lines are burning.
      Try to add a fuse atleast the fuse burns until you find the problem.

  • Pascual
    October 2, 2014

    Sir can i use MJL21193-MJL21194 instead Tip142-Tip147?

    • Auxtics Technologies
      October 16, 2014

      yes of course you can use

      • Pascual
        November 5, 2014

        if i use MJL21193-MJL21194 what is the max. supply voltage?

  • September 24, 2014

    Hi sir,
    I did this amp perfectly and also done 100w sub amp. Iam a +2 student.IAM Living in a villege In my area, fm signals not clear. Sir please suggest me a good fm anteena booster ckt. Please help me sir. Thanks

  • omer
    September 13, 2014

    100% working Stereo complete PCB layout of this amplifier including power supply on the single board is available along with all the building instructions and online skype support only for 5 US dollars.
    Visit our link

    For further information.

  • omer
    September 13, 2014

    Hello Guys , i have a complete PCB layout as well as circuit diagram of this great circuit in stereo form along with the power supply on the single PCB board.
    If any one is interested then feel free to contact me

    • February 13, 2015

      hi omer, is it for free, then i would be glad if you can provide me with what you have regarding this project.

    • John Benedict Acelo
      March 4, 2015

      Hi. Can i have one? Can i check it using Multisim?

    • Mirza Salman
      April 30, 2016

      Dear Omer, I have sent you a mail for pcb layout. I need one. Thanks

  • joy
    September 9, 2014

    what if i want to modify this cicuit. i want a 15 watt output.. what should i do?

    • omer
      September 13, 2014

      You can not obtain 15 watts from this specific amplifier.
      For 15watts you must go for tda2030 circuit.
      For more information
      Contact me

  • September 5, 2014

    Sir i again try it. But a proble is that, After 5 minute when play music the power transistors are damageing. I dont know what is the actual problem. I am using 27 0 27 volt 5 amp (+-35volt) transformer and 8ohm woofr. I also check the diodes it is working perfect. I use a wire loop between the base of 2 power transisters but no responce. I think that it is the problem of voltge. Please help me sir…….

    • seetharaman
      September 11, 2014

      Now cold check all components check the wiring thoroughly. Check your heat sink size. By shorting output transistor base is not having any response your driver transistor may be defective. Add 100PF ceramic disc capacitor between collector and base of Q3. Check whether the supply leads are quite short and decoupled properly.

      • October 11, 2014

        Hiii sir I like ur projects very much.. I made 60w inverter ckt but am getting 160v o/p sir plz help me and send me a 100w transister model inverter ckt with out ic ..sir plz help me…

      • daniel
        October 5, 2017

        hm sir I have tried this board but the place of speaker output is supplying voltage – , what should I do ?

  • September 1, 2014

    Sir i did this amp for stereo application 1 month ago. Its working fine. I made another one for my subwoofer it worked . But one problem, when i play music it condinue less than one minute then the power transistors are blooming very hot and a loud noise producing . I dont know what happent. Iam using 35volt 5amp dual supply and 10″ 8ohm jbl subwoofr. Please help me siq,

    • seetharaman
      September 4, 2014

      try fixing jumper wire between Q1 and Q2 base and switch on and try. if output transistors are getting heated up and only the sound is very much distorted check both the diodes.

  • August 25, 2014

    circuit diagram shows 8 ohm driver of 150 watt and description says 4 ohm. Please clarify. Thank you sir.

  • Lavan
    August 22, 2014

    Hello..I have plans to build a good sub-woofer. Can I use the same circuit for the same? Can some one point me to the PCB, sub-woofer box measurements? I believe now a days SMPS power supply’s available, can SMPS supply used to power this amp? Any guidance will be greatly appreciated. BTW, I am from Bangalore, anyone know what is the best place to buy these components?

    Thanks in advance

  • saikat
    August 11, 2014

    How many inch speaker i can use?????

  • anil babbar
    August 11, 2014

    sir I want to add a filter circuit to this amplifier which requires a separate power supply of +12 / -12 VDC at 3 amp, can you give me a power supply circuit that can supply +/- 12 VDC and +/- 35 VDC from a single transformer

  • saikat
    August 11, 2014

    in place of 0.33, 7 watt resistance can i use any other watt and value?

  • omer
    August 10, 2014

    I have made this circuit for more than 1000 times
    If you are in search of PCB of this circuit then
    inbox me

    I will provide you its PCB diagram 100% free of cost

    • Michelle Teoh
      November 10, 2014

      Sir, can I have your PCB diagram for this circuit? Thank you very much.

  • August 6, 2014

    Finally i did it. Its working great what a sound providing this amp. I really thank to seetharaman sir . God bless u.

  • August 4, 2014

    Sir iam waiting for ur replay…

  • August 2, 2014

    Sir i did this. But when i connect supply a noise is producing like “buuuu”. I think that my circut is perfect becouse i chek it somany times using the diagram. I dont know what happent. I use +/-32volt 5amp dual power supply and 4ohm 10inch speker and 0.5 ohm 10w instad of 0.33. When i connect supply, tip142 , 147 and 0.5ohm 10w become very hot. Now i waste somuch money to build this amp. I dont know what happent? I think that it is problem of tip transistors. Please give me a suggestion to overcome this sir, please……..

  • August 1, 2014

    If any problen Can i use +/-37 volt 5amp with 4ohm subwofr? What is the suitable voltage for handling 4ohm 10 inch woofer? Please help me sir? I want to build this in my school exhibition. Thanks

  • August 1, 2014

    If any problem when i connect 4ohm load with 27 0 27 v ac supplay? Is Tip transistors bloom ?

  • July 31, 2014

    Can i use 0.5ohm 10w resister insted of 0.33ohm?

    • usualfellow
      August 1, 2014

      yes surely you can use the resistor of 0.5E it will give more stability than 0.33E

  • Youssef Aly
    July 19, 2014

    I rebuilt the circuit on a breadboard with tip142, tip41c and four quarter watt 3K3 for a one-watt configuration. I test it with two computer power supplies (+12, 0, -12). TIP41C (no heat sink attached) feels cold, TIP142 and TIP147 along with the two 0.33 ohm 7 W resistors are HOT. The speaker goes half way to the negative direction and stays there with no sound coming out. Where should I check for pre-amplified signal and where should I check for drive signal from TIP41C ?

    PS: The PSUs are not exactly 12 volts unloaded, one is ~10.5 v and the other is ~11.3 v, both can supply 8 amperes safely on the 12 v rail. I have a (+45, 0, -45) unregulated power-supply, should I test with it or solve the issue at 12 V first ?

    • usualfellow
      August 1, 2014


      • February 23, 2015

        Hi,i am a Ryan, i have gone through this article here,what i wanna know is you said here, ” SPEAKERS SHOULD BE GOOD QUALITY AT LEAST 12″ 100-150WATT HANDLING CAPACITY” but i wanna know what should be the Impedance? 8ohms 150w or 4ohms 150w? I have a BPL cwx 59 model which has a Amp section made of TDA 2050 & i am gonna upgrade that for my mixing purpose,for the Lower end 20Hz-100Hz. I am geting confused as the pre amp has a section of 5band +/- 10db Graphic eq of 100,400,1k,4k & 12khz also with a bass boost,so if i boost the 100Hz with the Bass boost ‘ON’ that point of time the Speaker need a more wattage as well as the Amp…so what would be the proper wattage of the Speaker to use i am getting confused. Hence A little help would be appricated.

        The two questions are :
        1> 8 Ohms 150w Or 4ohms 150(If 8 Ohms150,i’ll use 4Ohms 300w)
        2> If i boost 100Hzs 10 db that raises all the frequencies 100 below,now with that if i make bass boost on (which is boosting from inbetween 70-80Hz & below, so what would be the wattage of the speaker?

        Thanking you,

        January 27, 2016

        hello ryan
        actually this amp delivers actual wattage of 150watts on 4ohms speakers, and 100 watts on 8 ohms.

      • Jagankumar
        September 5, 2016

        hi, this is Jagan , we are in the need of designing 150dB amplifier with speaker. please suggest me a way. how to achieve it. Currently we have designed amplifier with 125dB using LM3886.

  • Nick
    July 2, 2014

    How to start and what i need to build a very good sound amp

    • seetharaman
      July 2, 2014

      What are your expectation. Hope your budget will not be constraint, if so project can be suggested.

  • Youssef Aly
    June 30, 2014

    Sir, I built the circuit but I’m having problems, C2, C3 and R2 blowed up twice. I checked the traces for shorts but I found none. All capacitors are rated 50 V, R2 is rated 1/4 W. I’m using a 45 V dual supply. The TIP141 gets warm, TIP41C reflects wind like sound in the speaker, TIP147 is cool and on power up, the speaker cone moves forward and keeps it’s position until power is removed. Please help !

    • seetharaman
      July 2, 2014

      Check TIP147 collector-emitter must have become dead short check all your wiring and polarity of capacitors, if they are interchanged( plus- minus polarity of the capacitor) it becomes a link wire instead of an DC isolator. A thorough check is required including D1 & D2.

  • June 30, 2014

    thank u sir I did d same as u said and its working fine thanks a lot

  • June 30, 2014

    Pl print full diagram with sp arts name in colour &its veroo bird number

  • June 26, 2014

    Sir please give me a solution to solve ma problem. I have +/-40v 5amp supply. I made this amp. I using 4ohm subwofr. How can do to connect my woofr on my amp to get good perfomence. Is there any circut for connecting 4ohm load into 8ohm amp to get good perfomance? Please help….

    • Seetharaman
      June 27, 2014

      Connect one more 4ohms woofer in series.

  • June 25, 2014

    How can i connect a 4ohm woofer in a 8ohm receiver. Is there any circut for it? Please help me sir….. I hope ur comment

  • June 22, 2014

    sir I made d modification u told me i.e. Adding a diode n a 22/27 ohms in series with d two present diodes but am still having d crossover distortion.so I want to set the standing current but I don’t knw how to do dat (Whr to place the red and the probes)to carry out d reading and setting of the q-current. pls help me out sir.thanks

    • Seetharaman
      June 23, 2014

      You can measure the milli volt drop across R8 and set it for say you are using 0.47 ohms then 0.47 * 0.06A = 30 to 40 milli volt and set for this value. If you cannot measure milli volt accurately. Use current measurement in the collector circuit of Q1. Break collector of Q1 to positive supply line and insert an ammeter and set the current for 50 to 80 mA.

  • Youssef Aly
    June 16, 2014

    Hello, I can’t seem to find the TIP142, so I ordered TIP131f, is it ok ? I’m making a subwoofer amp by the way .

    • Seetharaman
      June 17, 2014

      Being a TO220 casing transistor it may get heated up and may blow. Use only TIP142 for better thermal stability as it has a better casing TO247. You may have to reduce the power output to <100watts with TIP131.

  • Lucas
    June 14, 2014

    Hi, ive built this amp but it seems that the bass response is too high. What can i do to lower the bass response, maybe decrease the gain?

    • Seetharaman
      June 19, 2014

      You can reduce the gain by increasing the value of 220 ohms of R2 to 470 ohms or 1K. That should take care.

  • usualfellow
    June 12, 2014

    3: use 0.5ohm resister ,in place of 0.33ohm and add 680pf in tip142/147
    I AM USING 2*12″ WOOFER ,AND TWEETERS OF 4OHM LOAD WITH +-42V 10 AMPERE SUPPLY & use 0.5ohm resister ,in place of 0.33ohm and add 680pf in tip142/147
    and the amp is running good trouble free since 1999

    • Seetharaman
      June 13, 2014

      Thanks for your guide line. This will help others to take care and successfully construct the amplifier without any doubt and safely investing their money on the project. Thank you once again.

    • john
      March 15, 2015

      Hello Sir, where/how should i connect the add’tl 680pf capacitor in tip142/147? across base-collector or base-emitter?

      • E
        September 14, 2015

        Yeah, i also wonder that. What i understand is:

        – One 680pf for tip142 with one leg on the base & other leg on collector
        – One 680pf for tip147 with one leg on the base & other leg on collector

        Is it true?

  • midhun
    June 11, 2014

    Sir what should be the heat sink size?and is it safe to use 4ohm woofer with +-40v supply?

  • usualfellow
    June 11, 2014


    • Seetharaman
      June 11, 2014

      Yes I have the original Universal Pre amplifier appeared in 1972 Philips Application book. I will send soon.

  • usualfellow
    June 11, 2014

    I CAN USE 2N3773 =IN PLACE OF 2N6254,

  • usualfellow
    June 11, 2014

    hi all use 0.5ohm resister ,in place of 0.33ohm and add 680pf in tip142/147
    i think than your amp go on without any problem ,i have made these changes in my circuit,and no problem

  • usualfellow
    June 11, 2014

    seetharaman sir,i have three amp i am using in this time as you said this TIP142/147, CIRCUIT IS same and modified version of philips circuit 1972, but believe me sir the low is very good in bd182 circuit in compare to this 150 watt circuit,am currently using it,
    sir i have also observe that using 2N3773 TR,is gives more loud and low frequency in compare to 2SC5200 TR,,I tried many circuit.
    so please suggest me ,even your subwoofer circuit made by 2n3773 is gives good low freq.

  • usualfellow
    June 11, 2014

    I am using preamp of philips amp made by mr. M.D hall,and it is giving terrific sound,with almost every amp,i have used it with more than 20 amps,gives terrific sound..

    in this 150 watt circuit i used 0.5/5watt resister,and rest circuit is same as above believe me than tere is no problem in your circuit

  • usualfellow
    June 11, 2014

    hello sir ,i made the jspyne circuit same as shown on site but it decreases the sound output.but your circuit has no problem iam using it since 2009 and believe me it is giving sound trouble free on 45-0-45,10ampre supply and 150watt load of speaker

  • Youssef Aly
    June 9, 2014

    Hello sir, I can’t seem to find the 0.33 ohm resistor in my country due to it’s high power rating and I don’t wany to order it online as it would be too costly, can I ommit it or replace it by a self made wire wound which I won’t know it’s power rating, or can you suggest other solutions ? Thank you in advance, regards, Youssef Aly.

    • Seetharaman
      June 10, 2014

      Hi Aly you may get 1 ohm 2 watts which is a standard value, use 3nos in parallel to get 0.33 ohms 6 watts.

  • usualfellow
    June 7, 2014


  • usualfellow
    June 7, 2014

    hello all i made this circuit in year 2009, and in first attempt ,the output is good ,but ihave seen the problem is of low frequency,this circuit delvers good output and good mid,and high frequency,but when we talk about low frequency,than it is not good ,i am using sub woofer also but there is no good punch,
    and jspyne circuit cuts the output from the original one so do not try that i tried it 4 times with 1% resistors,and caltron cap,but no use ,jspyne circuit reduce the output upto 50%,than there is no use,so please you people do not waste time
    I have used 45-0-45 volts 10ampre supply

    1.i have made many circuits from net,from efy and other books i have tried 47 diff.circuits but i have seen only one good circuit which is made by philips company based on the book of M.D HULL,THIS delvers 25/40 watt RMS output by 0-60volts, TR BD139,140 AND BD 182,and delever you good sound even you do not have good speakers .
    2. I am not criticizing anybody’s creativity but TRUTH IS THIS ONLY ,so please help me out ,if you have good circuit

    • Seetharaman
      June 10, 2014

      Hello that is the same circuit of Philips (from Philips 1972 Audio Application Book)I modified and used it in my Motional Feed Back Amplifier. In fact I have used 2 amplifiers in bridged mode to get around 150 watts into 8 ohms speaker.
      In the revision 2 of JSpyne the gain feed back circuit was changed to reduce the amplifier gain to R4 / R2 22K / 1K only 22 hence you require higher drive, comparing to original circuit. You can improve the gain by reducing R2 to 220 ohms. a gain of 100. 5 times better. It is customary to keep the gain around 50 in the output amplifier (for better frequency bandwidth)and increase the input through pre-amplifier to achieve the same output.

  • Tom
    May 16, 2014

    It is my plan to try to build this amplifier, however I have got some questions that I hope you answer:
    1. The specification says 150W in 4 ohm, do you know how much it will deliver in to a 8 ohm load?
    2. What size heatsink would you recommend?
    3. The transistors TIP 142 / Tip 147, would you recommend them in TO-247 or TO-220 housing?

    TIA and best regards

  • May 15, 2014

    I made this circut. It worked perfectly. After on day i use it for my home audio systen but one problem a deep noise is producing this ckt and 0.33ohm resistor heating very much . I give +/-35v 5amp power suply and 10inch 4ohm woofer. I dont know what happent? Please give me a solution sir… And i have one more qustion can i use 0.2 ohm instead of 0.33 ohm? I hope ur replay… Thankx…

    • Seetharaman
      May 16, 2014

      Use 0.47 ohms 5 watts in place of 0.33 ohms do not use a lower value. May be for interconnection you have not used proper screened cable. If you have a layout problem connect a low pass filter of 1K ohms resistance vs 470 pf in the input of the amplifier. connect also a 100pf capacitor between collector and base of Q3. refer (http://pcb.jspayne.com/150wattamp.html)

  • abubakar
    May 9, 2014

    Sir i,ve found my flaw n its r2 conncted in d junction of r8 I
    nstead of been in series with r4.after correcting it it works fine.u d best

  • May 5, 2014

    thank u sir 4 d response I will check dem n tell u d observations

  • john
    May 4, 2014

    hi sir!! finally i found the solution for stereo from single transformer,
    (the problem is tip 41 is linked with heat-sink now i disconnect the link the problem is solved. now it works fine thanks a lot.!!

  • sonu
    May 3, 2014

    Hello Sir
    sir I made this circuit first on bread board and it was working perfectly. but after 1 week when i made this again with new components this cicuit not working. . sir plz help me what should I do, i have to submit this project on tommorrow. . |
    kindly suggest me.
    Thank u

  • May 2, 2014

    sir I can’t figure out wats wrong with my amp after building it I tought it will work fine,but instead I’m only having a very little sound @ d output . pls help me sir. D one I made the first time worked fine. N I couldn’t get 3.3k @ 1watt so I used a 2.7k n a 750ohms resistors in series. Wen I read d value across d two resistor with my dmm it showed me 3.35k pls sir suggest me on wat to do.could it b dat my resistor combination led to d@ problem?

    • Seetharaman
      May 2, 2014

      No. you resistance combination is ok. Check C1, C2, C3, R2 and R4 for correct value or a defective component.

  • mian mubshir
    May 1, 2014

    sir how many voltge we can apply on its input .

  • April 30, 2014

    Sir i place tip142 and 147 on a heatsink, suddenly the loud noise stoped. Now there is no sound in my circut. I dont know wht happent.? Please help me sir

    • Seetharaman
      April 30, 2014

      Mostly transistors might have blown. Use cold check with a multimeter to find out damaged components. check the wiring and component values and polarity of each component used. use 33 ohms 10 watts resistance in positive and negative supply rail before switching on again after thoroughly inspecting the assembly again. If any one of 33 ohms smokes switch off immediately and look for the mistakes and correct it. Still if you cannot solve the problem kindly contact a local friend who is well versed in assembling high power amplifiers to help you. If this is the first time you are assembling a high power amplifier it is better take an advice from a local professional in assembling and proceed.

      • john
        May 4, 2014

        place mica sheet between tip142&tip147&tip41 and heatsink.check out and confirm there is no link between heatsink and those transistors.

  • john
    April 30, 2014

    Hi sir !! i bought another transformer for stereo….

    the transformer’s secondary voltage is 30-0-30 5amps,
    now the dc voltage is +60/-60 and 0(GND) after bridge rectifier.
    can i use this volt. or need any changes to this amplifier ckt??

    • Seetharaman
      April 30, 2014

      Looks like a poor quality transformer with bad regulation A 5amp transformer of 30-0-30 cannot give plus minus 60 volts it can give only plus minus 45 volts at the maximum. Kindly use series regulators and reduce the voltage to around plus minus 40 and use. for 60 volt plus minus this amplifier will get burnt you may have to replace all the semiconductors and capacitors with higher voltage rating, which are very expensive.

  • April 29, 2014

    Sir i use +/-35v dual power supplay and 10 inch 4ohm load. I made the pcb layout of this amp using the link you are posted on the site (http://pcb.jspayne.com/150wattamp.html)
    please solve my problem sir,

    • Seetharaman
      April 29, 2014

      Place a wire link between Q1 and Q2 base and energize and see if not getting heated up. It looks there is a problem in 1N4007 diodes. If it is still getting heated up check TIP147 for collector emitter short. Are using 18 SWG or better DC power connecting cables and are they less than 2inches. While switching what sound you are getting from speakers.

  • April 29, 2014

    Sir, i have one problem on my ckt. When give supplay to my circut a loud noise producing. I dont get 0.33 ohm 7watt. But i got 0.33ohm 2watt. I use 2 nos of 0.33ohm 2watt in series and connect parallel with another 2nos of0.33ohm 2watt in series. Tip 142 is heating very much and 0.33ohm resistor in tip142 is heating very much. Tip 147 is not heating. I dont know what is the actual reason of this. Please help me sir to overcome this . I hopeing ur comment. Please

    • Seetharaman
      April 29, 2014

      May D1 & D2 is wired

      • Seetharaman
        April 29, 2014

        May be D1 & D2 are wired other way round that is anode/cathode inter changed. Check collector emitter and base of TIP142 & 147 for correctness. Check the healthiness of TIP147. How much DC you are feeding to amplifier. What is the speaker impedance. What about the input to the amplifier whether connected to ground or left open. Have you taken care of short length of DC power supply cable should be less than 2 inches. Check all the wiring and your layout and DC supply do not exceed plus minus 35 volts DC. Please give more details to give a solution.

  • Akku#
    April 26, 2014

    Sir,the transformer shown in the power supply has a 30-0-30 output,can you explain how it get increased to 40-0-40 V at o/p after filtering.
    I am building a 5.1 amp,i have a 30V 6A single supply transformer for powering the 5 channels(2xTDA 2050+3xTDA 2030),after filtering the tranformer with a 4700mf capacitor how much voltage l get as o/p…??
    ,i am thinking to add 100W amp(mensioned in this site)for sub woofer,is this configuration is correct…..i’m a beginner .i really liked this site..frgve for my bad eng…..waiting for your replay…

    • Seetharaman
      April 27, 2014

      If you use 320 volt RMS AC voltage transformer the DC output will be peak of RMS voltage after rectifying and filtering. THAT is 30 X 1.414 = 42 volt s DC. you will get +42 0 -42 volts DC. you will get 42 volts TDA2030 will get damaged it requires a maximum of 36 volts for 4 ohms load speaker. use only 24 volts transformer. for TDA2050 it is ok as 44volt dc is max allowed.

  • April 18, 2014

    What is the minimum voltage required for run this amp?

    • Seetharaman
      April 20, 2014

      Minimum is + – 30Volts DC and Maximum is + – 45 volts DC with the components indicated. with + – 30 volts DC you will get 85 watts into 4 ohms load and 42 watts into 8 ohms load. with 45 volts 100watts into 8 ohms load 4 ohms load not recommended, will damage output transistors instantly.

  • April 18, 2014

    Sir what is the minimum voltage for this amp?

  • suresh
    April 18, 2014

    i need tip 41 eqiuvalent

  • April 17, 2014

    Thaks seetharaman sir

  • April 17, 2014

    Sir please replay me sir. I want to build a 5.1 system using above amp . So iam waiting for ur replay…

    • john
      April 21, 2014

      i m also want to build 5.1 using this circuit. i build stereo but this is not successful for stereo………….. but for mono this gives very good output.
      if u find any solution for 5.1 plz share here..thank you!!!

      • Seetharaman
        April 21, 2014

        Hi John this is a good stereo amplifier provided the layout is taken care by using thick cable for DC power supply and one point earthing and screen not connected at both ends etc. this project is not just for a beginner. High power amplifier are a bit difficult to assemble. this can be used or sub woofer amplifier and you can use TDA 2030 or 2050 for the surround front left, right and center speakers. This way you can achieve a nice 5.1 ssystem

        • john
          April 23, 2014

          sir thanks again for another reply!! i build this darlington for left right. And for subwoofer i use TDA7294 ic (100watts rms). and i use stk 4141 for center and rears. But there is a problem with this left right channels. both channels inputs are comes out through both left and right channels. this is only my problem. i use unregulated +44/-44 and GND power supply for all these amps from single transformer.is this problem? i think this is the problem. thanks again!!

          • Seetharaman
            April 24, 2014

            Proper decoupling and high value filter capacitors and proper layout and earth loops are a must to avoid cross talk between channels

          • john
            April 25, 2014

            ok sir … i ll try again …. and i ll show you that amp. thanks again!!

  • April 16, 2014

    Sir i don’t get 0.33ohm 7watt resistr. But got 0.33ohm 2watt. Can i connect above 0.33ohm 4 resistor in series to get 8watts? Please clear my doubt sir. Iwant to finish my circut. Please help me sir,

    • Seetharaman
      April 17, 2014

      you can use the standard 0.47 or 0.5 ohms 10 watts which are available readily in the market.
      If space is not at premium in your amplifier enclosure you can use 2nos 0.33 ohms 2 watt in series and connect in parallel with another 2nos 0.33 ohms in series to achieve 0.33 ohms 8 watts finally. Choice is yours.

  • April 15, 2014

    0.33 ohm 7watts resistor not available in my area. Only have 0.33ohm 2watts. What can i do for this. Please help me seetharaman sir. I want finish my amp when clear this problem. Thanks

  • April 15, 2014

    Plz sir i am waiting for ur replay……

  • April 13, 2014

    Can i use a rectifier ic for 6a5 diode in the power supply circut?

    • Seetharaman
      April 16, 2014

      Yes you can use 6A5 it is 6Amps 500v PIV rectifier.
      Please use any circuit which uses dual supply(both plus and minus voltage with zero volt reference)To get +12 volt use 7812 12 volt 3 pin regulator ic, for positive supply and to get -12volt use a 7912, a 3pin negative voltage regulator ic.

  • April 12, 2014

    Sir i want to builda a subwofr filter using my +35/-35v 5amp dual power supplay . I saw a filter circut on this site using +12/-12 dual power supply. Please give me a solution to convert 35v to 12v. Iam waiting for ur replay. Please sir ..

  • April 11, 2014

    I have +35v/-35v 5amp duel power supply. If i connect my supply to the power amp, how much power will get 10inch 4ohm load. Please clear my doubt sir. I’m hoping your replay, have a good day.

  • john
    April 10, 2014

    sir can i place one capacitor loop with one resistor from the positive pin of speaker to ground for my mingle problem? if i place it what happens?

  • john
    April 9, 2014

    AND i use this as subwoofer amp. gives GOOD output .
    BUT i m sorry to say this. THE output of stk 4141 for subwoofer is better this one.(for best effect i use the power capacitors value is 10000/50v*2 for dual)
    OTHER than subwoofer amp. . this darlington are rocks (better use for left right)

  • john
    April 9, 2014

    finaly i use split and pin protect ciruit power supply as you given the link. now i use single tranformer for two(stereo) channells. it works good. …………
    BUT. . . . one major problem that is the input of both chanells are amplifying through both channells. . that mean the input of 1st channel is amplifying through both channel. . AND also 2nd channell input also amplifying through both channels. . BUT no dissorted audio. CLEAR output. PLZ give some solutions for this . . THANK you sir!!

    • Seetharaman
      April 10, 2014

      Chech your layout. The power supply should run independant cables to each channel

      • john
        April 10, 2014

        i use independent circuit of output transistor pin short protection for each channels. and also completely i trace out the circuit for any mistakes. there is nothing to problem. except the ground(0volt) is common.i think this is the problem. because both speakers are looped with common ground volt. this may short with the other end of the output of each channels. but i cant understand this problem.bcoz of my poor knowledge.

  • April 9, 2014

    Thank you sir, god bless you.

  • April 8, 2014

    i use this circut as a subwoofr amp. If i use 25 volt 5amp ac with 10inch 4ohm subwofr what power actually get?

    • Seetharaman
      April 9, 2014

      You have to use 25 – 0 – 25 volt @ 5 AmpAC transformer with bridge rectifier and filter capacitors to get both +ve and -ve power supply required for the amplifier. please refer to the power supply circuit given in 100watts sub woofer amplifier.

  • john
    April 5, 2014

    plz help sir! i finished one channel. it works perfectly. but i made another channel for stereo. here the problem that the first channel input amplifying through both channels. and the second channel input is dead.(no audio) and also the heat is abnormal. what is the solution for this problem.plz help.

    • Seetharaman
      April 6, 2014

      If you are using single power supply for both the channels disconnect first good amplifier connect the one getting heated up by putting a link between Q1 and Q2 base the current through output transistors should fall and the if audio input is supplied it should sound distorted. If it is not achievable check the complete wiring and for a defective component, isolate replace and rectify.

      • john
        April 6, 2014

        i use dual power supply. i found the problem with power supply. that is i gave the supply for both channels from one tranformer.(this is the problem) AND i need solution for power supply for 5.1 using this circuits from only one transformer(sec=24-0-24). IS THIS POSSIBLE ??. If it is possible i m very lucky. THANK you for your response sir.

        • Seetharaman
          April 7, 2014

          Ensure all improvements are carried out as per following site
          Ensure each amplifier circuit is isolated by a diode and 1000uF in parallel with 0.1uF ceramic disc capacitor for both positive and negative supply.

          • john
            April 8, 2014

            ok i ll try sir, and thanks again!!

  • john
    April 1, 2014

    i finished this circuit it runs smoothly and there is no abnormal heat, wow!! great sound ………… its enough for an home!! before making this..i asked an shopper about 150 watt 5.1 amp. they says 3500 rupees for 6 channels. but this cost just 200 rupees per channel with big heat sink. so i m happily says “thank you admin”. now i m going to make 5.1 using this circuit

  • Rituraz
    March 24, 2014

    Good evening Sir can you please help me!I m new in electronics I can’t find tip142, tip147, tip41 Can I use other power transistor instead of these tips I like to making electronic kit. And I also want a perfect amp circuit diagram in one channel with parts list include watt which produce 200watt with deep bass. I m waiting for your answer. Thank in advance.

  • saeed
    March 12, 2014

    can i use a 4ohm speaker instead of 8ohm ,which is written in the first figure?or i need some modifications?

  • Trollman
    March 11, 2014

    Hi, i wanted to ask, can this circuit be used with an antenna rather than a speaker???

  • amer
    February 18, 2014

    Sir can bc558 be replace by 2n3906 ,and tip147 and tip142 replace by note 270 and note 271

  • raymart
    February 15, 2014

    nice circuit

  • abubakar
    February 7, 2014

    sir I have finished assembling dis circuit and d sound is quite good bt d only problem am facing nw is one of d output transistor heating up (2sb1560) but d oder transistor (2sd2390) heat is normal.pls sir how can I fix dis problem? am using bc557 at d amplified stage

  • abubakar
    January 21, 2014

    pls sir I cldn’t find bc558 can I use bc557 instead? n I have d2390 transistor is it dsame with 2sd2390? Pls sir am waiting ur reply sir thanks

  • abubakar
    January 20, 2014

    dear sir seetharaman, I am new to electronic n I have so much interest in building dis circuit.pls sir I need ur assistance.Whr I am I couldn’t find bc558 and tip147. Pls sir I need to knw wat other transistors can I u instead? I will b waiting ur reply sir. Thanks

  • omer
    January 14, 2014

    Hi… Seetharaman sir i have question for you sir..
    i have designed this amplifier in stereo and using dual transformers 25-0-25 for each channel and using a stereo pre amplifier ( bass treble kit) .. All is ok the amplifier is working perfectly and giving me a pure 150 watts output i think more than 150 watts because its running my 4 12 inch speakers very smoothly…
    I am facing a problem when the amplifier’s sound is low then it does not give a clear output it gives me a distorted output and when i increase the problem it gets fine…
    i need to know that what is the problem exactly ?

  • Aqeel Ahmed Khan
    January 13, 2014

    sir pl Sher PCB Lay out 150watt amplifier circuit & ton control

    December 31, 2013

    Sir Happy New Year and im still Waiting for your reply on my Post

    December 13, 2013

    Sir how can test the Tip142 and 147 to know if it is dead. My first circuit worked perfectly and what if the fuse is removed, will cause the transistors to over heat. This circuit im doing now is mine. But the other one i did i sold out. Please i need ur reply as soon as possible my father is on my neck. Thanks alot. I will be waiting. Or send it to my Email address (princestechnology@gmail.com)

    December 12, 2013

    Please what if the fuse is removed can it affect the working of the circuit. My question is that what is the work of the fuse. Please i need reply urgently Thanks for reading.

    • Seetharaman
      January 4, 2014

      By deleting fuse your protection to the amplifier is lost in the event of speaker leads are (amplifier output) shorted both the output darlington transistors will blow off. You can test the transistor with a multimeter in diode test mode. being darlington transistor forward continuity of base emitter junction will be 1.2V and Base collector will be 0.6. collector emitter in reverse bias will be 0.6 due to built in protection diode (see internal details shown above)and forward continuity will be open circuit.

    December 9, 2013

    Mine is working perfectly. I love Circuitstoday or even circuitsforever. Thanks im getting rocked

  • Andrew
    November 21, 2013

    Circuit works great! Is there any way to increase gain in preamp stage? I’d like to use a phono directly, and been having a hard time eliminating rf noise

    • Seetharaman
      November 23, 2013

      Hi Andrew go to the following site modifications indicated to be implemented for stable reception.
      http://pcb.jspayne.com/150wattamp.html first circuit is good enough. if you have layout problems then use second circuit.

  • Biju Raj M.K
    November 19, 2013

    Please help me. 0.33Ohm 10 watt(connected to TIP 147) resirtance very hotted up and no output

  • G S Khokhar
    November 1, 2013

    To enhance output can I use BDW83C & BDW84C in lieu of TIP 147/TIP142 or any other MOSFET? Kindly suggest. After changing Transistor how should I combine two sets (left & Right Channel) of amplifier to produce enhanced output. Kindly draw a diagram. How much supply DC votls and Amperes need for Single pair and combined pair?

  • Krishna Reddy
    October 2, 2013

    Hi all,

    I have a couple of 32-0-32 volts @ 4Amp and 40-0-40 volts @ 5Amp trafos lying around at home.

    So I thought of building an amp which can use them. Any schematics for something like this? I haven’t searched on the net, maybe there are some amps out there. In terms of audio quality, the most important thing is CLEAN and BALANCED sound. We need to hear the little things!

    I was thinking to build a set of mono block amplifiers, not too fancy but nice enough for my Dynaudio Audience 42W speakers. Can someone help me point out some amplifier designs? Think I can handle a build completely from scratch.
    So what is a wise decision? I estimate, with these supplies you should get around 150 watts.

    Thanks In Advance
    Krishna Reddy

  • September 25, 2013

    sir if i want to continue the output stage with one or two power transisor where will i connect the base of the transistor

  • Tilen
    September 15, 2013


    Im not sure whats wrong with my circut because if i mesure the pins where is speaker output i got 37V,and tip41c get really hot but the other two are cold (Im testing without speaker and MP3 only power supply). I hope you could help me with solving the problem. Thank you.

  • malinim
    September 3, 2013

    I would like to drive an 11 ohm speaker from this 150 watt amplifier. I only require a 105 watt output. Using TIP142GOSND and TIP147GOSND both rated for 100v@10amps, I estimate the supply would require around +/- 90vdc. The circuit appears to be able to handle the load if I use all components rated for the increase supply voltage. Do you recommend and changes to the original design? or have any suggestions to drive the 11 ohm load?

  • Rex
    August 29, 2013

    Seetharaman, i cant find 6A5 diode. But i have 6A10 DIODE can i use it, or will the current be too high?

  • Rex
    August 29, 2013

    Seetharaman, i cant find 6A5 diode. But i have 6A10 DIODE can i use it to replace 6A5

    • seetharaman
      August 30, 2013

      Hi Rex you can use 6A5 is 6amps 500PIV rectifier. 6A10 is 6 Amps 1000vols PIV rectifier. both are suited for the project.

  • jayanath
    August 9, 2013

    Request indicate the best circuit for public address system amplifier. with use of 18 inch horn.

  • Rex
    August 7, 2013

    Seetharaman, i want to make the POWER SUPPLY CIRCUIT but i cant find 6A5 doide. Please i need other Doides for replacements.

  • Rex
    August 7, 2013

    Seetharaman, i want to make the POWER SUPPLY CIRCUIT but i cant find 6A5 doide. Please i need other Doides for replacements

    • alele moses
      August 7, 2013

      my brother rex you can use 6A10 diodes it gives a very stable dc it is 10000 volts and 6A

  • omer
    August 4, 2013

    We have built this circuit about more than 1000 times this works well and perfect..
    If you are facing any type of problems regarding this circuit then you can contact us any time….. we are here for your assistance
    We have a complete tutorial ( images as well as videos ) of this circuit’s building procedure…
    If you are realy willing to built this circuit with perfection then contact us below given mail…. we are here to solve your problems… thanks , have a good day

  • omer
    July 30, 2013

    If anyone wants this circuits clear PCB layout then please visit my link
    by clicking on the tab “150watts amplifier PCB board”

    www . it-tronics . blogspot .com


  • alele moses
    July 27, 2013

    someone help me with this, i used a scopemeter(CRO) to monitor the progress of the input signal from the signal generator into the amplifier and at the emiter of Q5 there was less amplitude than from the base and and moving forward it was becoming less and less please i need to know was it because of the lower voltage (-+22.5) i used or there could be some other problem please could it be darlington transistors thanks

  • alele moses
    July 18, 2013

    hi seetharman, i switched on the power supply and the tip 142 heated up very first and eventually the volume of the speaker deminished,the tip 142 cooled and i again switched on the power supply but there was no heat as if the tip 142 was dead. even there was no sign of heating in tip 41 and tip 147 are they dead.i also want to know how i can get some results of the amplifier using the signal generator and the CRO coz i tried and there was no change in the output from the CRO with respect to the input signal ie there was no amplification effect, how can i get this.

    July 16, 2013

    sory for the mistake the speaker impedence is 4 ohms please read my coments below this

    July 16, 2013

    i used the lower voltage because some of my components were at first blowing and burning with higher voltage but i think i can now increaase the voltage thanks to mr seetharman for your wonderfull work

    • Seetharaman
      July 17, 2013

      Hi Moses you can increase the supply voltage to + / – 36volts DC (the upper safe limit with 4 ohms speaker).

    July 16, 2013

    Hi mr seetharman thanks alot for guiding me up to this point the circuit is working but i used +/-22.5V to power the amplifier and the output was low,i also noticed that the TIPs are not heating as expected,i used a DVD as my audio input. so my question is, could it be the low voltage that i used or my TIPs are dead? the speaker is 150watts 5ohms.

  • ben
    July 16, 2013

    nice amp works great…i assembled 8amps with this circuit good high freq. and low frequency response using jrc 4558 ic as tone control..i used it for lead guitar, bass guitar & keyboard…i even use tip41/tip42 & tip2955/tip3055 as darlington pair as output x’sistor with supply voltage of +/-40vdc @6amperes…using dual voice coil speaker @ 450watts 4ohms…heat is minimal low noise no hum…

  • omer
    July 16, 2013

    150 watts tda2030 / tda2050 subwoofer amplifier circuit now available here

    www . it-tronics . blogspot . com

  • turk690
    July 15, 2013

    This circuit works, but D1 & D2, which are supposed to provide the bias for the “A” part of the class AB description, can come from anywhere and therefore have unpredictable actual forward voltages. Garden variety 1N4007 diodes can have forward voltages ranging from 0.3V to 1V! The lower this voltage gets may result in audible crossover distortion, and the higher it is, Q1 and Q2 may conduct heavily (more A than B, at all times including no-signal conditions), become very hot and die if not properly heatsinked! It would probably matter little if this was a lower-power amplifier (<40W), but for a design that aspires to 150W, a transistor in place of D1 and D2 whose base is connected to a pot that can fine tune the bias voltage is essential, IMHO (the www is filled w circuits for this).

  • Olabode
    July 14, 2013

    Dear daniel,ur problem of over heating on this amplifier configuration can be solved by changing only one copmponent on the circuit.For more knowledge on this,email me on “olabodejoseph@gmail.com”

  • daniel
    July 13, 2013

    well, i used a heat sink for TIP142, but wasn’t that big and i also placed a fun beside it which reduced the temperature to some extent, but the sound still distorts and diminishes eventually. when this happens, i turn it off for it to cool. when turn it on it takes a longer time for it to sound and the sound is even very low and noisy.i will have to turn it off and wait for a very long time, even though the tip142 is cool before it sounds. it doesn’t end there, it still over heats and the same thing happens again……Anyway,tip 147 doesn’t heat at all. it remains cold while tip 142 becomes hot. i don’t know if there is something wrong. it looks like all the work is on tip142. I will get a bigger heat sink to try and see the results.

    • omer
      July 14, 2013

      you must replace your both the transistors …… thats not the issue of heatsink

      • daniel
        July 14, 2013

        okay, thank u very much. but then i want to know, tip142 and tip 147 are darlington pair transistors with side base, but i do a diode-test of these transistors, they read as side base and they can also read as if they are center base. is that the nature of these transistors? that is how they were when i bought them from the market.

    • Seetharaman
      July 14, 2013

      Hi Daniel may be your TIP147 is dead short between collector and emitter. check with the multimeter for this and if required both TIP142 and 147 with a matched pair transistors.

  • alele moses
    July 13, 2013

    hi seetharman i used +-22.5V to power the amplifier and every connections seemed to be ok but when i connected to the signal generator for the input signal,the output from the CRO(CATHOD RAY OSCELOSCOP)was smaller than the input meaning there was deamplification instead.please i need also to know into details how the preamplifier and darlington pair works on my email ,could it be yhe lower voltage i used please coment.thanks regards.

  • daniel
    July 12, 2013

    Hi Mr. Seetharaman, the amplifier is now working, but tip 142 becomes very hot when i power it, and the sound eventually becomes noisy and finally diminish.in any case i am using c558 instead of bc558. i don’t know if it is going to be a problem.

    • Seetharaman
      July 13, 2013

      Hi Daniel Hope you have used a large heat sink for TIP142 & 147 (a good extruded alloy heat sink not less than 6″ X 2″ X 2″)

  • alele moses
    July 12, 2013

    Hi mr seetharman my capacitor C2 10mf 100V blew of when i powered it but before blowing it was not allowing the signal input to flow untill i had to shotit,please could there be any problem with this capacitor or could it be some where else, coment (these are the changes i made, i replaced 0.33ohms with 0.47ohms 5W and i used 120pf capacitor instead of 100pf and two 15-0-15 3A TRANSFORMER in series insted of 30-0-30 5A)the way you wrote to me and my power supply was +46/-46V.

    • Seetharaman
      July 12, 2013

      please go through my 11th july comment and give the results.

  • Rex
    July 11, 2013

    Seetharaman, thanks for this 150W AMP circuit, but we need high power amplifeir like, 200W, 400W, 500W etc

  • alele moses
    July 10, 2013

    hi mr seetharman, i powered my amplifier with -46/+46 volts power supply that i made using the 2 15-0-15 3A transformer and the 220 ohms resister got burnt so i am asking my self could it be that the resistance was too small or the watage i used and i have bought half watts instead of quarter watts please coment on this. i also want to use the signal generator and the CRO to determine some x-tics of this amplifier.please coment on this.

    • Seetharaman
      July 11, 2013

      Check polarity of C3 and also for a collector base short circuit in Q4 or there may be some wiring mistake or transistor leads identification wrong. 1/4 watt is sufficient for 220 ohms.

  • daniel
    July 8, 2013

    thank u very much for the reply.i have done the modification and it can now pick the sound of the mp3 at a lower volume. but it gives a hazy sound with background noise “puf…puf” with breakage in the sound what can i do to get a clear sound?

    • Seetharaman
      July 9, 2013

      Hi Daniel you may please go through my 2nd July comment. Implement all the modifications indicated in the second circuit it should take care of all your layout problems.

  • Rex
    July 5, 2013

    Seetharaman, Thank you for your response, what about 1N5408 Doide, can it replace 6A5 Doide?

    • Seetharaman
      July 7, 2013

      Hi Rex 1N5408 PIV1000 and IF is 3 Amps only. Try using 2 nos in Parallel.

  • Rex
    July 4, 2013

    Hello, Can i use 1N4007 Doides to replace 6A5 doides in the power supply circuit?

    • Seetharaman
      July 4, 2013

      Hi Rex 6A5 is 600volt PIV, 5 Amps rectifier diode. You can use any 200PIV 5 to 10 amps rectifier 4 nos or a single 6 amps 400PIV bridge rectifier

  • Rex
    July 4, 2013

    Can i use 1N4007 Doide to replace 6A5 doide in the power supply circuit?

    July 2, 2013

    hi mr seetharman i was able to get 8 ohms 800 watts speaker,can this work for me. trhanks

    • Seetharaman
      July 4, 2013

      Hi Moses you can use 2nos above amplifier in bridge mode to drive 800watts speaker with reasonable quality. If you can get 100 watts 4 ohms speaker use two nos in series to achieve 8 ohms 200 watts.

    July 2, 2013

    please i have failed to get the speaker of 8 ohms,please some alternatives

  • daniel
    July 1, 2013

    thank you very much.but my problem is;
    -i have built the amp and it is working, but the sound is very bad. i also have to open my mp3 player to the maximum volume before the sound becomes stable, which is even a bad sound. what can i do about it?
    -also, the voltage specification of the capacitors. whenever i go to buy the components, i am challenged with the voltage, since one capacitance value can have different voltages. are there any means of detecting the voltage required?

    • Seetharaman
      July 2, 2013

      Hi Daniel check with no signal input to amplifier check the current drawn by the output darling-ton pair (by measuring their collector current) It should be between 50 to 60mA if not adjust by adding a resistance of 10 to 27 ohms and a diode IN4007 in series with D1 and D2 once this current is achieved it should work nicely.
      Refer modified drawing in the following link

  • mehru
    June 29, 2013

    HI. I can’t find speaker of 8 ohms with 150 W. Is there any alternative?

    June 24, 2013

    Thanks mr seetharman for your advice and am doing it but i need image of the pcb connection of both the power supply and the amplifier on my email if possible the videos of the connection.please sir i need this because i want to avoid loss of some components due to connection mistakes because we have very limited components in the market.

  • atamosa
    June 23, 2013

    hi good day to you mr. seetharman….my question is…how to connect in serries of two 15 0 15 3A transformer to get 30 0 30 6A?…..plz reply with this question….

    June 20, 2013

    we also have other types of transformers but with less than 3A, my phone number is +256779268591 please i need your help on this gud time

    • Seetharaman
      June 21, 2013

      Hi Moses use the full winding without center tap of 15-0-15 3amps transformer. It will be 30 Volts. Use one more transformer in the same way in series ensure it gives 60 volts end to end if not interchange one of the transformers secondary winding connection. it will be 60 volts end to end. and use the inter connection between transformer as center tap. Now your power supply of 180 watts is ready. this can easily power your amplifier one channel. do the same for other channel also.

    June 20, 2013

    Hi mr seetharman i have almost made all my connections but my main problem is the transformer. we only have 15-0-15 3A transformer in the market please advise me about this,i also need the pcb connections in my email(alelem@rocketmail.com) may be if possible the videos.thanks

  • Gordon
    June 20, 2013

    I am looking at this circuit and cannot understand how 2 X 1n4007 diodes are able to bias the output transistors (darlingtons) into conduction, surely you would need at leat 4 diodes, to bias the 4 Vbe junctions? Yet many have built it and say it works well, what am I missing?

    June 17, 2013

    I WAS thinking of using 15-0-15 3A AND 15-0-15 2A in series coment on this sir.

    • Seetharaman
      June 18, 2013

      Hi connecting two transformers in series will increase the voltage but the current will be the same, if they are identical transformers. this is the basic. Please conduct the experiments and give a feed back by using different complex combination of transformers. please check your mail.

    June 17, 2013

    thanks mr seetharman for u reply but there is one thing confUsing me about the transformer coz last time u told me to use 2nos 15-0-15 3A transformer and connect in series and it will give 30-0-30 6A my question is what about the TIP 142 AND 147 transistors which requires maximum current of 5A, WONT THEY OVER HEAT WHEN I USE THOSE TRANSFORMERS IN SERIES SINCE THEY WILL PRODUCE 6A.

    June 14, 2013

    sir i think sending me a full report may also help me understand this amplifier into details.please i need a report for this design on alelem@rocketmail.com thanks

    June 13, 2013

    Thanks alot Mr seetharman for your reply coz you have given me another hope of coming out with what the project requires and i think i need to know how you are coming out with some of this calculations of like the output power, input signal and the output voltage of the power supply.may be on my email;alelem@rocketmail.com, good day sir.

  • Alele moses
    June 11, 2013

    sir, i was able to get 0.47 5W resistor that you told me about except that i couldnt find the 15-0-15 5A transformer and am going to use 15-0-15 3A TRANSFORMER and i will try to measure the output voltage.what do you suggest about the fuse coz am still using the 5A fuse and am going to use the 6A10 diodes in the bridge but am not going to change other components in the power supply appart from what i have stated above.i hope i shall go to the amplifier after the power supply.thanks alot mr seetharman for your wonderfull work i have already learnt alot even before finishing the project.meet tomorrow.

    • Seetharaman
      June 12, 2013

      Hi Moses you can use 2nos 15-0-15 3amp transformer in series to get 30-0-30 6 amps. with the above power supply and 4 ohms speaker you will get 150 watts output with 8 ohms speaker around 100 watts out put power with an input of 300 milli volt rms signal.

    June 10, 2013

    i have failed to get 15-0-15 5A TRANSFORMER and am thinking of using 15-0-15 3A transformer. in this case what will be the output in volts of the power supply, what about the output of the amplifier in watts,and what will be the magnitude of the audio input.please we have only 3A transformer and less in the electronics shops of our city and thats why i have choosen now 15-0-15 3A transformer thanks, your reply will be appreciated

  • Mike
    June 10, 2013

    so i could just slap 5 9volts on this bad boy just to see if the circuit works aye?

    June 10, 2013

    Thanks alot mr seetharman.i tried looking for the 15-0-15 5A transformer but i didnt find it in the all of our city but instead i found 15-10-15 3A transformer and our laboratory technician advised me to use it and determine what it will give at the output of the power supply and my question is what will be the output voltage of the power supply if i use 15-0-15 3A TRANSFORMER, what will be the output of the amplifier,and what should be the magnitude of the audio input,will there be any adjustment in the other components like the bridge rectifier and other components in the amplifier.thanks your respond will be appreciated sir and i hope i will learn alot from this project.

    June 10, 2013

    am going to look for 15-0-15 5A transformer but can i use 6A10 diodes in the rectifier circuit instead of 6A5 thanks.what other alternatives are there for 0.33 ohms 7W resistor coz i dont have them in our electronics shops.

    • Seetharaman
      June 10, 2013

      Hi Moses 6A5 is 6Amps 500Volt PIV rectifier. 6A10 is 6Amps 1000Volt PIV rectifier. you can use. In place of 0.33 ohms you can use 0.47 or 0.5 ohms 5watt if both are not available use two nos 1 ohm 2 watt in parallel. you please send me your mail to seethasub@hotmail.com

    June 8, 2013

    thanks alot mr seetharman for your wonderful work i want to use acombined bass cut and treble out filter please advise me about the connections and if possible send me the details on my email including how to connect it and the circuit including my new circuit and again am having problem of getting a transformer for the power supply am in uganda and today i checked all the electronics shops in our city but i didnt get transformer 30-0-30 5A, i got only maximum of 18-0-18 3A i didnt get 0.33ohms resistior for amplifier but all other components were there except diodes for the power supply instead a got 6A10 and i wanted to use it instead.please advise me about the possible adjustments and if possible the circuit diagram on my email coz i dont want to give up for this amplifier.i also have a maximum of 12-0-12volts power supply in our laboratory and i prefered it instead of assembliong anew power supply please advise me about the possible adjustment for this power supply and the circuit diagram of the adjustment.thanks

    • Seetharaman
      June 9, 2013

      If you can get 15-0-15 volt 5 amp transformer can be used as voltage doubler circuit to feed +40 & -40 volts to amplifier. You can use the dual supply indicated in the following link. That can be adopted for any voltage.

      You can use the passive tone control using TL072 appeared earlier in Circuits today can be used with the above amplifier

  • June 7, 2013

    Interesting concept. Can you tell me where is it mainly useful? I mean in which cases we can frequently use this?

  • Alele moses
    June 4, 2013

    i wanted to put this circuit into another use.please help me about this and may be how to connect it for another use.

    • Seetharaman
      June 6, 2013

      Hi Moses please give for what use, then we can suggest.

  • rakesh
    May 30, 2013

    will it maintain clearity like hi-fi systems,
    plzz reply am thinking to go for dis

  • moses akwenya
    May 30, 2013

    these circuit schematics are very good for electrical/electronics/computer/telecommunications engineering students

  • bhaskar
    May 22, 2013

    Hi, i want to use this 150 watt amp or your 100 watt sub woofer amp circuit for my car. is it possible. how to convert 12v DC to 36v/45v DC. pls help. if possible send via email. thanx

    May 20, 2013


  • May 13, 2013

    helow. good to u sir.
    this kind of circuit amplifier, will it work in astereo circuit??

  • Neeraj verma..
    May 11, 2013

    Plz sir if you have a 12 audio stereo amplifire circuit then plz give me..

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