GS-1 buzz/noise (ground loop?)

[weemies]

I'm having a buzzing problem with my Headamp GS-1. I don't know if it's a ground loop or what, that's what Justin suggested. I've had the amp for some time now, and until now I've just lived with the problem, keeping the GS-1 volume low, and cranking the volume from my DAC.

I also have a Gilmore Lite, and it's dead quiet, using the very same source. I'm using a step down transformer with the Lite though (I'm in Europe, 230V zone).

My output chain is:
RME Fireface 400 (a firewire audio interface) -> Benchmark DAC1 -> GS-1 -> HD600

Both the headphone and the loop outs give out this buzz. Haven't tried the preamp outs. When I turn off the GS-1, the buzz remains. When I unplug the GS-1 from mains, the buzz is gone. The noise also disappears when I unplug the source from the selected GS-1 input.

I've tried switching audio cables, and I've also tried going straight from the FF400 to the GS-1. Different cables didn't change anything, but the noise actually changed a little, when I went straight from the FF400 to the GS-1. With the FF400 as the sole source, the GS-1 buzz became a bit quieter, and also included a random pattern-like noise, like morse code or something. I guess that might indicate there's a problem with with the power at my house, but that could only a part of the problem, because once again, the Gilmore Lite doesn't do this.

Any advice would be appreciated. Justin suggested a cheater plug, but here in Europe, the electric cables are different than those in the US, so there is no obvious third spike for ground.

 

[Andrew_WOT]

If you are running coaxial, try toslink between soundcard and benchmark.
Had the same problem, cheater plug works like a charm.

 

[socrates63]

It does, indeed, sound like a ground loop issue. I've had a similar issue when using the USB out from my laptop to feed my DAC and amp. I added a M-Audio Transit and used the optical out and that cured the problem, as Andrew suggests.

What else do you have connected to USB or Firewire ports? I suggest unplugging everything connected to your computer as well as other electrical appliances in the same room and begin by connecting your DAC and then the amp.

If you don't want do go crazy trying to isolate the problem, then utilize a optical output from the PC.

 

[dvw]

Quote:

Originally Posted by weemies /img/forum/go_quote.gif My output chain is: RME Fireface 400 (a firewire audio interface) -> Benchmark DAC1 -> GS-1 -> HD600 Both the headphone and the loop outs give out this buzz. Haven't tried the preamp outs. When I turn off the GS-1, the buzz remains. When I unplug the GS-1 from mains, the buzz is gone. The noise also disappears when I unplug the source from the selected GS-1 input.

Indeed you have a ground loop problem. But I don't quite understand what you mean by turning off the GS1 and the buzz remain?

Any way, the ground loop appears to be between the DAC and the amp. Two possible solutions.

1. Connectthe chasis ground of the DAC and Amp together and see if that help. Use a cable and connect it any metal screw and the metal chasis.

2. Alternatively, get a ground loop isolater which is a transformer that isolate the ground.