150 Watt amplifier circuit
Description
This is the cheapest 150 Watt amplifier circuit you can get,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 transistorsQ5 and Q6 are wired as pre amplifier and TIP 142 ,TIP 147 together with TIP42 (Q1,Q2,Q3) for driving the transistors.This circuit is designed so rugged that this can be assembled even on a common 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.
Circuit Diagram & Parts List .
Notes.
- 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.
TIP 142 & 147 Internal diagram and pin out.




Hi sitharaman
Thank you for your reply
The polarity of the diodes is correct
Where i have to check the standard current please tell me
In series with the supply positive and negative lead. one at a time if you have one meter only.
if a device need 12volts 1 ampere but we give 12volts 4 amperes?what will happen?will the device works or get burn??
@ADNAN – nothing will happen, just the transformator (that is supplying your device) will not get hot when working. if you give your device a transformator with 12V and, for examle, 750 mA, it could work but probably not too long. ampers define strenght of transformator, so its like if u need $1.000 every mont but u get $4.000 it will be easy for you to survive but if you need $1000 and you get only $750 you will die :p …hehe….
@ADNAN – if u have speakers that need 150W of power and 24V, that means you need: (150W / 24V) = 6.25A for speakers to work at full strnght but its recommended that you use 7A
a transformer have rating 50-0-50 500va than how much ampere of transformer is this?
500V/A…? are you sure..? thats alot… thats 500W meaning max 10A on 50VAC ..is that a microwave transformer..? :p
no meex its for a 500watts amplifiers
if i have a power supply of 30 volts 12 amp.Is this is possible to get 30 volts 6amperes from the 30volts 12amps power supply????
if i have a power supply of 30 volts 12 amp.Is this is possible to get 30 volts 6amperes from the 30volts 12amps power supply?
Hi Adnan yes you can use for any current from 0 to 12 amps at 30volt. Voltage will be constant as per load requirement the current flow varies. the current consumed depends on the load resistance.
its mean i will vary both of voltage and current as my load requirement????
plz send me any example or any circuit on my email or here with variable voltage n current power supply??
Hi Adnan you will be feeding constant voltage to amplifier but its out put voltage to speaker will vary as per the loudness you want. since speaker is of constant resistance the varing voltage to speaker will produce varying current through the speaker hence the wattage.
I searched the thread, and didn’t see this question. Does anybody have a jpg of the PCB? I would like to make a PCB using laser-printer method, but need a pic. If anyone has done a layout with a PCB creator, please post a link.
Thanks,
Scot
Hi Scot
try the following link. it gives full details including the PCB
http://www.diyaudiotr.com/islecler/tammetin.php?metinid=6&durum=e#sonyorum
Hi! seetharaman
i want q1 and q2 to be TO3 type can you tell me the model of TO3 casing transistor
also tell other corrections to the circuit if i use TO3 type
You cannot use in the input stage, TO3 transistors which will generate lots of noise and input impedance will be very low. you have to use low noise small signal high voltage transistors in the input stages.
Hi seetharaman
in the given diagram Q1 and Q2 are not input stage they are in output stage
now tell me the TO3 model instead of TIP142 and TIP147
if we use TO3 type what changes have to do in the circuit
Hi Shreya sorry i got confused bet 100watt sub woofer and 150 watts. TO3 equivallent with higher power is MJ3001 / MJ2501. if you cannot find them use BD139-2N3055 with BD140-2N2955 as compementry pair for the out put stage with external resistances and diodes to achieve protection.
can you give me the resistance values,diodes and how to connect if you have circuit diagram you can send to mounicashreya@ymail.com
can i use 2n3773 instead of 2n3055?
HAI GUYS STILL I AM USING THIS CIRCUIT ITS WORKING FINE AND GREAT CAN I USE 75 0 75 IN RAIL VOLT IT HANDLE
any one please help me can i use 75 0 75 7 amps in rail for this circuit i am having 55 0 55 transformer this okey
Hello seetharaman
can you give me noise reduction circuit for this amplifier
Hi Shreya the resistances are shown above use 8.2K and 39 ohms you can use BY127 or 1N5404 for the protective diodes.
Hi Jagadish the maximum voltage for transformer is 32-0-32 @ 4amps or higher.
Hi Emmi noise reduction (DNL) at the input of the amplifier.
can i use 2n3773 instead of 2n3055?
hello. sorry o bother you with another transformer related question but i need a powersupply 2 of these amps i have recently built. i can get a 35vac 600va transformer for a resonable price, do you think the amps can take it or is +49,5 0 -49,5 volts to much ?
for 2 amps *
And what would the °C/W be per amplifier if the transistors shared heatsink? the best i can get around here is 1,1°C/W
or could i use a intel p4 heatsink with fan ?
hi if i use 35-0-35v @4A will the amplifier works or not?
hi admin wheres the seetha raman
Hello seetharaman,this circuir required a dual volt supply,but i don’t have a 30v-0-30v transformer,however if i used a 12v-0-12v transformer will this work.You can e-mail me at ajdeane03@yahoo.com.
can i use 35-0-35v @4amp with 6amp bridge with 2x4700uf capacitors for this amplifier?
Hi seetharaman
subject: 100watt sub-woofer
i shorted R9 & R10 the temperature of transistors decreased but Q7 is getting hotter than Q5 why ?
Hi Adnan 35 0 35 will give a DC of 50volts which will lead beyond the maximum dissipation of the transistors may damage the output transistors with transients. 30 0 30 will be ideal for 8 ohms speaker. with 35 0 35 use 15 ohms or higher impedance speakers.
can i use 2x8ohm speakers in series at 35-0-35v @ 4 amp
Hi Adnan why not please go ahead use a good heat sink for output trasistors. use 2amps fast acting fuse for + & – power supply line to protect output transistors during an inadvertant shorting of speaker wires.
this is jagadish thank you seetharaman can you please tell me any ic handle 75 0 75 volt and 7 amp
other wise stk 4050 v where i can find
hai Onkelf i used processor heatsink with fan
cheer jagadish
hai seetharaman but tip 147 and 142 can hadle 100 volt right ,other wise can we change any resistor value to reduce volt
and also please tell me how to reduce 55 volt to 30 volt using resistor value
regrads
jagadish
power supply for Tda7295 ic transformer 24-0-24v @4amp with 6amp bridge with 2x15000uf capacitor is OK or any addition in capacitors are needed?
Hi Adnan This will be the best power supply suited for this IC. for filter you can add 0.1uF ceramic in parellel with the 15000uF to take care of HF instability.