That seems like its running a little warm to me. The noise coming from the amp probably is the power supply; I can hear a slight noise coming from the power supply in my dac, snd two external power supplies that I have also. The hiss is normal too in my oppinion; be thankful it's not a hum (ground loop hum) because if the hiss is slightly bothering you, a ground loop hum would drive you nuts. Removing your ground pin might lead to shocking results ;-)
Hum inside adcom amp and hiss at tweeter
I just bought a used adcom 5503 and noticed it has a hum inside the front of the amp. I think it's the toroid making the noise. Up untill this amp there have been no noise or hiss of any kind from my system. I have a marantz sr7005 as a preamp and have an adcom 555 that I was using until I got the 5503 and it was silent. Also had some marantz ma500 that were silent. The 1 thing I noticed was the buzzing is altered when I power on and off my receiver. Does that mean it is dirty power? Also the amp seems to run super hot. I measured it at 125 deg f at the heat sinks. Does this seem to hot for low level listening? It does take a while to get that hot like 2+ hours. What I was going to try was the cheater plug without the ground and see if maybe I have a ground loop. My speakers are b&w 683 and are 8 ohm so the load is not that bad for the amp. Thanks for any advise. Mike