Pass F5 Power Amp

[fdlsys]

Thanks mate, I'll give it a try.

[HighFidelityGuy]

It sounds to me like a ground loop problem, possibly caused by the phono lead shields (signal 0V) on both channels being joined together at more than one point along the signal path and then possibly being joined back together again through another route like a chassis ground. If that makes sense? I would try and check each piece of equipment and see if the signal 0V from the left and right channel are joined together and also if they're joined to chassis ground. Try to make sure that they only join together in one place, preferably your amp and also that they either don't connect to chassis ground or only connect to it once. Or something along those lines. I'm not an expert on this type of stuff but I've had similar issues in the past and that's the advice I was given. I had to resort to using a ground isolation transformer between my preamp and subs.

Good luck.

[fdlsys]

Makes sense, thanks!
Grrr... I hate de-soldering...