Nice find. I have owned 3 adcoms and had good luck with all of them. They are built like tanks.
That's a great amp for a great price. I used to have one mated with an Adcom 5500 and an older Adcom 555 II (for a 7x200w setup) driving a set of very inefficient Dynaudio speakers until I switched to my current Rotel 7 channel setup (RB-1080/RMB-1095) to get back a little room in my cabinet. Frankly, I can't tell the difference between the two setups other than form factor-the Adcoms are one of the best "bang for the buck" product lines available, especially the older models, and the amps will drive pretty much any speaker that exists-I think they can handle a 2 ohm load in spec, but I don't have the data sheets anymore. Just remember to use your legs when you pick up that bad boy off the floor; otherwise, you'll be enjoying the sound with a back brace.
If you want to see some serious power supply components, pop the cover off and take a look at the massive toroid and capacitor bank inside. BTW, I had my 5503 set up for the front three speakers so I could swap amps in and out of the side and rear channels-that setup worked very well.
