The last week or so I’ve been getting an intermittent static in one channel of my Aleph J. It comes and goes. Sometimes quite loud then later almost disappears. Amp is four years old and has been very reliable and basically dead quiet until now. I opened it up and don’t see any loose connections? This is a dual mono amp with two separate power supplies in one chassis if that’s relevant.
if static measurements (offset, Iq) are OK, revisit each and every solder point, recheck mosfet tightening to hsnks
No, it’s definitely the amp. Tried swapping channels and noise stayed in the same channel. Also tried output into a different amp to the speaker and it was quiet.
I once had something similar with a DIY F6 and it was a cold joint on a binding post. So don't forget to check that as well.
Check that insulators haven't failed by measuring for open circuit between middle pin and heat sink.