motorola hi fi power

Posted on Feb 7, 2014

The first thing that you must do, is to measure the end transistors (T3 and T4) amplifying coefficient, the hfe or ². 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 ½turning on ½ you must short circuit the input

motorola hi fi power
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s 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 uA.

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