How long it take before your system/amps sound

I have Atma-Sphere M60s in a medium sized room. In the summer, I can not leave them on for more than 45 minutes before the room gets too hot. The AC will kick in and the AC noise pretty much destroys my listening enjoyment. The M60 consumes 600 watts total at idle and don't know how much my AC consumes. I would be wasting energy leaving them on all the time. But I can't forget the little glimps of heaven I had after 12 hours of leaving them on. It's winter now, so don't have to worry about the AC

About 45 minutes. I play both sides of an LP before it sounds right.

Dracule,

You aren't listening loudly enough if your air conditioning is ruining your listening experience. :)

After two hours of warm up. SS equipment.And time of actual playing...not sure, probably an hour or a little longer. I did try a few times to leave it on for couple of days and heard no difference.

Fiddler, I have a dedicated 2 channel audio room that has been extensively treated. The room is dead quiet...the noise floor is almost nonexistent...no traffic noise, no noise from household appliances, no electrical noise, etc. Listening at around average of 80 to 85 dB in a room like this is plenty loud. 90 dB would give me a headache. So when the AC kicks in, the sound can be very annoying.