G'Day Tweek48,
I suggest removing the input coupling caps. This will remove any leakage due to them and the signal switching stuff on the inputs.

The amp of course will not work with an input.


I would strongly suggest that you use a cheap speaker to do this. 500mv is rather high for the dc level and could damage the speakers.

Firstly track down the noise problem then you can adjust the DC level and bias.

Before you replace all the caps, it is really good to find the offending part. (I find a small pleasure in taking it all out on that part)

BTW don't do this in bridge mode.

Regards Scott