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Re: One step at a time.

Hi Peter:

I've made some progress using this approach.

I disconnected the coupling caps (both the 4 .1uF caps from the bias pcbs and the 2 .47uF caps to ground, correct?). MOST of the noise dissappeared, however I still have some low hum, prob. 60hz, present.

Reconnected coupling caps. Noise present, loudest in left channel. However, it will occasionally drop out, and things are relatively quiet. I suspect I have a loose connection in that channel somewhere, I just haven't been able to track it down yet.

I did some further tests with the volume control. Starting from lowest position, I can raise the volume pot quite a ways without any increase in noise. Then I reach a point where the noise decreases dramatically to where it is almost inaudible. With any additional turn of the pot, the noise increases rapidly and is very, very loud.

In conclusion, I think it's clear that I am looking for 2 sources of noise. The first is in the power stage, the second is ?? A final question: When shorting the signal inputs (step 2, previous post), should I short them to ground, or connect them to one another?

dv

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