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
Al, have you ever hi-jacke4d a thread? If I were you I would seriously consider it.
The back of PSB speakers are biwire & I use AQ Comet

Proper connections are top half treble(red/black)
bottom half bass (red/black)
I was doing top half treble+bass(red&black)
Bottm half treble+bass(red&black)

2high pass
2low pass
I was connecting high/low + high/low
Which AQ speaker cables are you using? IIUC, they would have to be a thinner gauge for the treble than they have for the bass before a miss wire would mess up the bass.

If the treble wire was thin enough it would conceivably get worse as the cable got hot.