Jeff, I don’t believe you will hear a difference in weather or not you have a 20amp breaker or 15 amp unless you’re running full tilt maximum output, which I doubt it if you in an apartment. The only way the breaker will come into play is if you suck more power that it can handle and it will trip the breaker. Now, that being said if you have a dedicated line for the amp with nothing from the rest of the apt on it, then that will sound cleaner due to isolation tho no the breaker size. As far as harming the amp: well I have be running a Krell 300c on a regular 15 amp line for years with no issues but I don’t play my music at ear shattering levels. My amp was built in the late 1990s and is working fine to this day. It does run run a little warm being class A however I like the Class A sound. I’m sure there are many amps out there that will sound a bit better but I’m pretty happy with this one for now. If you’re really concerned I’d call Krell.
Can you put a Krell in an apartment?
As you see I am a total "goner" living in a cheap apartment with about 50 grand in Audiophile equipment. I am looking at purchasing an old krell "FPB 400 CX" amp that the manufacturer says needs a dedicated 20 amp line. Can you still run this amp off a regular electrical outlet? If you can, will it sound like crap?