When I plug it into things such as a guitar amplifier, or TV...seemingly anything I spose....I get this high pitched line noise.

Any ideas on the matter?

Update.

I tried plugging it in just to the BOSS pedals, and it's clean from there as well.

So I'm not entirely sure what the cause is.

Ground loop perhaps. 60 cycle hum from the guitar amp. Bad grounding somewhere.

Tried plugging it into the "Subwoofer" output on my cheapie radio system thing (it doesn't have RCA outputs for the other channels) and it didn't make the sound either.

Hmm...but it does do it on my friend's TV and on his Fender guitar amp which isn't even a crappy one.

I wonder what the heck the problem is.

That's what I was thinking.

I noticed that doing things on my computer seemed to have an effect, though, curiously enough...

I was thinking that perhaps the ground loop thing was the problem, but wanted to see what you fine fellows had to say about it .

I just hope I don't run into this when I'm recording from the record player.

I'm wondering if there's any way I can get around this problem or if this is just an inherent flaw with the hardware that I'm stuck with.

Any other ideas, guys?