Bass leaves after amp warms up?

Fishing716 mentioned also on another thread that switching sources can bring back the bass. Same happens when he "adjusts" speaker cables. It would imply bad connection somewhere. It is not amp because he tried two, not source since he switched them, not speaker cables because he had this with spades, bananas and direct wiring. I also believe he tried different speakers? It is not line voltage since he stated it is 120V. It is not outlet because he tried few.

Is it related to equipment or room/building? It might be bad connection somewhere in the building (defective breaker, loose screw in the panel etc.) I would set-up the system with small speakers and just CDP to verify that it is still happening and then would get it to my another house.

I considered defective jumper from pre-out to power-in but Bryston has switch.

I said "to my another house" - it should say "to friend's house".

I hope it is the house, as hard as it is to change, because the only alternative is Fishing716 himself (common factor) - musician, 60's, LSD. If that's the case he has to be brought up at completely different forum of "experts".

I'm making jokes but I feel your pain Fishing716 and read your other threads on the subject. You'll find it eventually, I'm sure.

Foster_9, that's true, some amps are better than others but his amp plays fine for couple of hours and then looses bass. Switching source or adjusting speaker cable can bring back the bass performance instantly.

Fishing716, what about amp's power cord? Is it possible that you used the same cord with both amps? Defective cord would be better news than defective house.

Csontos, I did read it but never experienced such big effects from wrong bias. There might be some temperature effect on Mosfets' rds(on) but I cannot imagine why amp would suddenly play fine again after changing source or moving speaker wire. I was asking if the same power cord could be the cause but no answer. I was suggesting trying in different building to isolate the problem, but got no answer to that as well. I'm out.