This is a very simple, low
cost, Hi-Fi quality power amplifier. You can build it 5 ways, like it’s
shown in the table (from 20 W to 80 W RMS).
- The first thing that you must do, is to measure the end transistors
(T3 and T4) amplifying coefficient, the hfe or â. If their disagreement
is bigger than 30 %, the amplifier would not give a clear sound. I used
MJ3001 and MJ2501 transistors, and this disagreement was around 5%.
- Before the first “turning on” you must short circuit the inputs of the
amp, and put a mA-meter on the output, than turn the amplifier on, and
tune the R13 pot, to decrease the DC current on the output, to some
uA-s, or in a lucky situation to zero. I was able to decrease it to 10
I am very contented with this amplifier.
It gives a very good sound quality.
Have fun with it!
6. 5. 2005.
Download this project in .doc format