I just got a brand new kicker zx500 amp and hooked it up in my car. I don't have a sub hooked up to it because UPS is slow. When the amp turns on it makes a very faint high pitched noise, maybe like 10k hz, its not audible sitting in the drivers seat but if you put your ear up to it you can hear it, so I doesn't really bother me. Is it normal for an amp to make noise?
I have the same noise from my Earthquake. It's only noticeable when I'm just chillin' at night and nothing's playing. It works fine though. Yeah, that's right, MS. :P