Princeton

[JC@]

I have a princeton AA964 on the bench, and it works perfectly good except that it has very little volume, maybe this is normal I don't know for sure as it is my first princeton.

All controls respond as expected, even the breaking in comes where expected too, but the volume is definetely too low.

Where am I loosing signal? Output tranny maybe?

[JC@]

Improper bias. Now fixed.

[Mandopicker]

What was it biased at before...and what did you bias it to after the solution.

Just curious...

[JC@]

What was it biased at before...and what did you bias it to after the solution.

Just curious...

I didn't measure the current, but I checked the bias voltage and it was about -70 volts if I recall right. The amp had a simple adjustable bias circuit mod and that was the closest to -34 volts it would go, changing a resistor now has a range that goes from -35 to -45 volts or so, and at -35 it sounds right, I have to take current measurements and fine tune accordingly.
This amp comes from a recent repair so I guess they forgot to check the bias in the circuit they installed.