150w amplifier

Hi all, i did this amp and i have cross over distortion as u can c in my attach, also they say to add volume control fit 10k pot inline which does not work i can only get the volume right with a 1k pot. Can u please help me set the biasing right to get rid of the distortion as i dont want to half dismantle the pcb, can i maybe use other diodes etc and what do i need to change to get the volume control right. Im building this amp for poorer folk who want something quite powerfull for outdoor entertainment just as a speaker box amp basicly. I just want it to sound descent at all volumes pls someone help. https://www.eleccircuit.com/cheap-100w-to-150w-amplifier-ocl-hifi/
Txs john

If you could kindly render the circuit in a conventional way (in on left, out on right, + on top, com on bottom) and not use text-speak, you may get some help. Frankly, I am far to lazy to wrap my brains around this. E

Hi e
if u just click on the image and enlarge it u will see where is in, out, pos, neg, ground.
Txs john

Hi e
if u click on imgage and enlarge u will see where is pos, neg, ground, in, out.
Txs john.

It's a really, really, poor amplifier - and not capable of 150W.

A simple improvement would be to replace the two diodes (which will cause crossover distortion) with a Vbe multipler so you can adjust the bias. I agree with canadaelk, it's an apallingly badly drawn 'circuit', as well as been a very poor design as well.

Its schematic was saved and posted as a very fuzzy JPG file type instead of as a very clear PNG or GIF file type.

The poor TIP42 driver transistor has a max voltage rating of only 40V but its supply is 90V so it will quickly fail. It should be a TIP42C that has a max voltage rating of 100V.

The total supply is 90V so the p-p output swing will be about 84V. Then the output will be 29.7V which is only 110W into 8 ohms, not 150W.

not 150W.

Click to expand...

Ah, but those are peak-to-peak pink-noise-weighted music watts, not real watts

The output of that horrible amplifier is 150 Whats or 110 Watts.

audioguru said:

The output of that horrible amplifier is 150 Whats or 110 Watts.

Click to expand...

Not off a single pair of TIP141/142's

You'll get 100W+ off two pairs though.