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
You may be dealing with the inherent shortcomings of the gear

I took that into account that is why I've tried over the last 6 months
3 amps,2 pair speakers and a partridge in a pear tree
Okay, but the operative here is that 'nothing' is perfect. Ivor Tiefenbrun, the inventor of the famed Linn Sondek TT started his quest after buying a system way back when and taking it home only to discover it had no semblance to reality at all. Well, he took it back to the store complaining it was defective. They unapologetically informed him that no, this is exactly how it should sound. He then(thankfully) went on to correct some of the problems. You clearly need a partridge in a pear tree.
Okay. Not following your question. Atmasphere's first post is what I conceded to and my subsequent post is the position I hold. Simply my opinion FWIW.
You have spent too much time dealing with this. There's only one thing in common and thats PSB speakers, which doesn't mean the integrated amps you've chosen aren't the problem. It sounds like your dealer is no help at all. I would find a new one or call mine. You need someone that can start you off on the right foot. My dealer would be at my house right now if I wasn't happy. I'm serious. He would be sitting in my living room on a Sunday night.