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
Fishing, definitely appears to be a very high quality integrated and I do hope this new amp works well for you, however someone has misinformed you about the power. The ratings I quoted was from the company's website.

http://www.accusticarts.com/pdf/produktblatt/power-I-mk3.pdf

Agree with Mapman, what's on paper never tells the whole story.
I'm with you Seikosha. I very seriously doubt that Fish's audio gremlins have anything to do with the amp.
High damping factor for perfect speaker control
What does this mean?

listed under features of amp I'm about to audition
Damping factor is speaker input impedance/amp output impedance. High damping factor means lower amp output impedance. Amps with high damping factor are better able to control driver movement, when needed. Some speakers will benefit more than others. In general this should help produce a clean, detailed articulate bass as opposed to one that is less controlled, looser sounding, or possibly muddy. This will likely be of benefit with more full range speakers like the PSBs that tend towards lower impedance in the bass frequencies. Amp damping factor can be a significant factor in how one amp might sound compared to another.