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
Sorry, Mapman. I misunderstood. I thought you were suggesting to get one just to test the theory. My bad.
In order to use a power amp that means purchase of a preamp as well,correct?
No, not necessarily. As I suggested previously, you could borrow or purchase a separate power amp, and drive it from the pre-out jacks that are provided on your M6i. You would then be using only the preamp section of the M6i, together with the separate power amp.

Regards,
-- Al
I will ask my dealer Audio Salon if he would lend me an amplifer to try this procedure.
Also to Ralph,I tried your suggestion of pulling out interconnects when the bass fails then reconnecting..
I'm afraid that didn't work.

AP
If someone lives close by in NYC would be welcome to come here & troubleshoot.
I admit not being an expert on these matters
Perhaps I'm doing something wrong
As I have followed this post and looked around on the net, I just found this review on the AudioPrism III conditioner. I believe Fishing uses the II, which is very similar. What is interesting is the comment made in the 3rd paragraph from the end. They also make reference to a similar conditioner. Hopefully someone with more technical knowledge can explain why they say this.

http://www.soundstage.com/revequip/db02.htm
.