Comments on: Easy 100 Watt Power Amplifier

By: tahir

tahir — Fri, 08 Jan 2021 18:48:17 +0000

i use same circuit with a power supply of 25v positive negative and find it working perfectly

By: Ron Hoffman

Ron Hoffman — Thu, 25 Apr 2019 13:17:34 +0000

I took a look at the schematic and know what the problem is. It is called crossover distortion. This results because the two diode drop does not provide enough voltage to bias the output transistors when they are idling at zero volts. The output transistors are Darlington types that have twice the base-emitter voltage drop as regular transistors. To correct this problem, you need to add one more diode and a small resistor, 22 ohm, in series with the two diodes between the bases of the two output transistors. Simulations indicate that this should eliminate the crossover distortion. The T4 and T5 emitter resistors should have 6 to 8 mV across them with no signal input. This means about 20 mA is flowing through the output transistors at idle, which eliminates the crossover distortion. Hope this helps. Good luck.

By: D. Khumalo

D. Khumalo — Tue, 26 Feb 2019 14:56:09 +0000

I built the Amplifier but it sounds like there is a leaking capacitor, Audio is very low and slightly distorted. Initially I thought that one of the Darlingtons was gone but after testing them they are ok. I then discovered that my power supply voltage was at 49 – 0 – 49. I am still working on it, any helpful hints are much appreciated