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
HI AL

What is the goal of what what you are discussing?
(which I don't understand)
Can I ask when you listen to both versions if one sounds more satisfying than the other?
What is the goal of what what you are discussing?
The goal is to characterize the symptoms as precisely as possible, in technical terms. Hopefully that would help to identify or at least narrow down the possible cause(s).
Can I ask when you listen to both versions if one sounds more satisfying than the other?
Hard to say. Partly because neither sounded satisfying, due to the excessively hot treble, and to some extent also due to a general lack of transparency. I have no way of knowing, of course, the extent to which all of that may have been contributed to by the original recording, vs. your system's reproduction of it, vs. your recorder and microphone.

Also, as I indicated, precise equalization of volume levels was problematical, which further increases the difficulty of making any judgments.

Can you provide an answer to my question about whether or not your recorder applied AGC and/or peak limiting when your recordings were created? If you are not sure, let us know the make and model of the recorder. If an external microphone was used with it, let us know its make and model as well.

Regards,
-- Al
AL I petitioned my dealer to lend me a dedicated 250 w amp from Musical Fidelity.
Do you feel this will resolve the problem?
http://www.musicalfidelity.com/products/m6series/m6prx/

Musical Fidelity M6 power amp to be borrowed next week