Bass leaves after amp warms up?


I don't understand-after my Musical Fidelity M6i amp warms up for about an hour I notice the deep bass & kick drum aren't the same.
They sound less musical with loss of weight/depth.The notes are there but the moving of air have left.Sound is has much less impact and boreing.
I had the same problem with Bryston amp so there is no defect with amps nor with the rest of my equipment/
PSB Synchrony one speakers,AQ cables,Bryston CD Player.
My question has anyone heard similar & is there a plausable reason?
fishing716
No. But if you have problems again when you install it, you will know what to do.
yes,send it back..
I'm sure I tried the system w/o conditioner more than once.
I don't understand why dynamics seem to be regular this time.
About 36hrs
Sound has now changed again..
This will be my last post till I have a solution.
Thanks
Hopefully the new amp is coming this week and will help pave the way out of hifi hell into utopia.