Grounding problem: I'm clueless


Hi folks,

I'm getting a serious buzz/hum through my speakers when listening to vinyl.

Equipment:
-Kenwood KD500 w/Rega RB300 arm and Grado Gold MM cartridge
-Antique Sound Lab Mini Phono tubed phono stage
-Audio Aero Prima hybrid integrated
-Silverline SR15 monitors

The previous owner of the phono stage attached a ground plug to the outboard power supply, he said it got rid of the hum for him. No such luck here. I've tried running a ground cable from the turntable to the preamp, and from the turntable to the power supply. It's quieter when attached to the power supply, but still not really acceptable.

Some more info: power is being filtered through a Shunyata Guardian. Once in a while I'll heard a very faint radio signal through on of the speakers. Not sure if any of that matters, but there it is.

Any advice would be much appreciated.

Thanks!
128x128lousyreeds1
YOu have somje RFI if you can hear radio through your system. Some Phono stages are prone to this. The 47Labs is one in particular. Where are you hookig the ground/drain wire to on your turntable?
Hi folks, thanks for the advice.

Opalchip, I just tried to isolate the cause as you suggested. The phonostage without the TT going through it is reaaallly loud. When I plugged the TT directly into the amp, it was silent. Does this mean that my phonostage and amp aren't getting along? Is there anything I can do?

Thanks again.
Hi - Sorry for the delay. There are so many possibilities that it's pretty hard to say what's going on without being there.

Assuming all the plugs are polarized (either 2 prong with one big/one small or 3 prong), the first thing I'd try is a "star grounding" pattern of sorts by grounding every single piece in the system to a single point that you know is good - on the amplifier if it has a specified ground screw, or on the Shunyata if it has a provision for that.

Another thing I'd try, if the condition of the tubes is unknown, is substituting them. I don't know the ASL's but I assume it's a pair of 12ax7's or similar which aren't hard to come by. If you don't have spares maybe someone nearby could lend you a pair to try out.

Also since it really appears that it's the Preamp/Power Supply and not the TT, I'd call ASL and talk to them.

Another remote possibility comes up because your amp is of European origin. The grounding scheme/wire colors are different over there, and sometimes people doing mods or setting up equipment to run here get the polarity reversed.
If you want to double check everything, here's a chart of what the internal wiring should look like if it was done to accepted standards:

__________________Ground_____________________Hot_____Neutral

Europe____Green/White or Green/Yellow__________Brown_____Blue

USA________________Green___________________Black_____White

USA Plug type____Round prong_______________Small prong___Large prong