Loss of bass & full spectrum sound


Can anyone shed light on my audio system problem?
I have PSB Synchrony one,Musical Fidelity M6i + cd player & turntable along w/video
The sound is Full with deep bass then after an hour it reverts to a different unenjoyable presentation with no life..
This has been going on in my NYC apt for about a year
I have a great sound then it changes (white-washed).
I adjust speaker cables(AQ biwire comet)& occasionally it regains a full body sound however after about one hour it's gone.
All my components have been checked to function properly.
I suspect an electrical problem but voltage is steady 120
Any similar experiences?
fishing716
My Amp is Brand new(Musical Fidelity M6i) after replacing a privious brand new amp (Bryston B135).
It's unlikely the power supply capacitor is failing in my amp.
What you said about RFI is worth investgating
My prior statement that the system changes when warmed up was not accurate..
There is no reoccuring pattern when the sound will changes.
The kick drum & heft behind the bass lasts up to 72 hrs.
Has anyone tried Highwire powerwraps to rid RFI interference?

http://www.musicdirect.com/p-7195-highwire-all-clear-rfi-coils-pr.aspx

http://www.musicdirect.com/p-7194-highwire-powerwrap-ea.aspx
Clearly, no one here has had those interference issues to warrant an expenditure worthy of paying more than the cost of the ear buds Kijanki is promoting on another thread. I bought two pair. Problem solved.

A few suggestions:

1.
Use 10 gauge or 8 gauge speaker wire. Get the Belden 5T00UP (10awg) or the Canare Star Quad 4S11 (8awg). The thicker cable will offer less resistance than similarly designed smaller gauge cable. In my experience, I get deeper bass with the larger gauge cables. If you're bi-wiring, get a pair of speaker cables per speaker, even if you get the Canare 4S11.

2.
If you have a source with Balanced output, use it instead of RCA.

3.
Get to audition an isolation transformer type of power conditioner, such as Torus Power or Bryston BIT units.

I'm also in Manhattan and I have experienced something similar some years ago with another system. I did some experimentation a few years back looking into the effect of speaker wire gauge and bass response. Using cheap speaker wire, I found out that as the wire got bigger (smaller gauge), I got deeper bass and a more balanced sound.

Also, in my system, I get better bass response using copper wire instead of silver. Silver provides better definition, but I get a more balanced sound from top to bottom using copper-based cables.

I hope this helps.
Not likely. But I agree with everything you've said. IME, you really do need 8awg, all the way to the power supply itself. Change it out in your amp and you'll be blown away.