2. amps-preamps
  3. 1236409165

Strange ground loop...?

Hey,

I just hooked up a new amp and I'm having a strange noise issue. Only in my right channel, I get this high-pitched whine... maybe around 2khz. My left channel is dead silent.

The problem seems to be an interaction between my DAC and my amp. If the DAC is off, the amp is silent.

The amp is an 84' yamaha, so the cord has no ground. There is a ground screw, though, and I have connected that to my power conditioner, hoping this would solve it... nope.

I've tried plugging the amp straight into the same outlet that the power conditioner is plugged into (into which the DAC is plugged in). That actually did work... but I don't want to run my amp straight into the wall.

I suspect I just need to find a proper place to run that ground wire...

Any ideas?
djembeplay
djembeplay OP
179 posts
 
Sooo... actually there is no need for me to run straight into the amp from my DAC... I know it will be perfect. It has been that way for a few days and it was fine. Also, the fact that it goes away with my pre-amp turned up all the way indicates that something is awry in that area of the chain.
djembeplay OP
179 posts
 
Sorry for all the posts -

Ok, what I'm going to do is try a different amplifier and see if the same thing happens.
jea48
4,605 posts
 

03-11-09: Djembeplay
I just wanted to add... this distortion, again, completely goes away with my pre-amp turned all the way up.
That rules out ground loop hum imo.....

Humor me and try another source other than the DAC.
I think the problem is the DAC
djembeplay OP
179 posts
 
The thing is... it sounds perfect when I run my DAC directly into my AMP.

OK, so.. here's what I just did:

I didn't use my other amp (integrated) simply because I didn't have the right terminals on my speaker wire. I did, however, use it solely as a pre-amp feeding my amp (whereas the pre-amp I have been using was a little passive w/ volume control).

Using my older integrated as a pre-amp, the noise was MUCH MUCH worse. Again, it was primarily in the right channel.

I switched the RCA's connected at the back of my power-amp, and sure enough, the distortion completely switched channels as well. So, we know it isn't a malfunction on the part of the amp I suppose.

It must be line interference somehow... I really don't get it still.

I'm now going to try connecting my amp chassis to the ground on my temporary pre-amp.
djembeplay OP
179 posts
 
Ok, Chassis on amp connected to chassis on DAC or pre-amp = zero difference at all (full distortion still present).
More to discover