996: Stereo constantly hums when on (CDR22, Hifi/Nokia amp)

[slknv]

So for about a month now, when I turn on my radio (CDR22) there's a constant low humming from the speakers. Stays there with FM or CD, doesn't change with faders, doesn't change with revs. Goes away entirely if the stereo is off.

I suspected a bad ground somewhere, so I pulled the CDR22 out and checked the amp - nothing much that I could detect. Of course it doesn't use standard RCA connectors so it's a little hard to narrow down which one is at fault.

Don't suppose this has happened to anyone else? Or is there anyone in Melbourne who's upgraded their car and might have a spare head and/or amp that I can temporarily swap in to try and diagnose the source of the problem?

I've got about 4 old head units and same amount of aftermarket amps in the shed I could install, but I kind of like the old school aesthetic of the oem unit.

[Masterwerk]

I'm going through the same thing with a customers car at the moment. The problem appears to be in the head unit. James at Soundlabs is checking it out, I'll let you know how I go.

[slknv]

Yep, was the head unit. I bought an adapter from ebay that would allow connection of RCAs to the Nokia amp, hooked up a spare ancient kenwood unit and bingo - no more humming. I did like the stock look, but the new/old unit has bluetooth and USB at least.