A strange phenomenon

A few months back a very similar thread was started here by a poster with PSB speakers and a Musical Fidelity integrated. Going by memory alone, I believe he posted under the moniker "fishing716". Over 500 responses came in. See if you can dig it up in the archives. Tony (his name), are you out there?

Incidentally, the sanest response he got IMO came from an audio dealer in the NJ area who had dealt with a similar problem for a client and determined that there was a connection arcing over in the system owner's service panel which they discovered by darkening the room where the panel was and observing the periodic flashes as they occurred in the panel.

Again, going by memeory, it seems that fishing716 finally determined that the speaker wires were hooked up icorrectly but that never satisfied me because his system (like yours) would play fine for an hour or so and then suddenly go lifeless.

Perhaps it is an electrical supply problem to that outlet or the panel.
There is a surge and then a lag and the amp cannot compete with the irregularity. Personally I would be concerned with a "short" or some other
safety/fire hazard issue and bring an electrician. Last question, is there a periodic large power draw, like a well pump etc. Not an electrician but have
experienced dimming lights for no reasons etc. Lastly, I wonder if the
voltage regulators, capacitors or similar devices within the amp are functioning correctly.

Maybe after a few hours of listening you just get tired or bored. Your mental state could definetly affect your perception of the sound
Alan

If there is no technical problem such as something with your ac or one of your components, then it could simply mean that you have a poorly matched system that once warmed up just doesn't sound good. A system's sound will change when it goes from being turned off and cold to being on for a while and warm. Some never turn off a system because of the warm up process unless they have a system with a tube amplifier. You do not provide any information on your system. It could be the basic issue of amp-speaker matching (the foundation of any good system, imo). Putting together a good-sounding audio system with a separate amp, preamp, sources and speakers can be a real challenge. It requires research, auditioning, listening, trial and error, as well as simple luck sometimes. You can hit and you can miss.