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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
rar1's avatar
rar1
1,784 posts
 
On the face of it, it sounds like you have a ground loop somewhere. Was the hum introduced into your system when you introduced the turntable? Also, by a ground plug, do you mean a "cheater" plug (converts 3 prongs to 2 prongs)? If not, then a cheater plug for either the phono stage and/or turntable could be the $1 solution.

You can also try plugging either the phono stage and/or turntable directly into the wall socket (bypass your Shunyata Guardian) and see if that takes away the hum.

If you have your cable TV hooked up into your system, that could be the culprit as well. The $100 solution then, would be a product from Tributaries called a "Ground Loop Eliminator." It is available from Audio Advisor .

Regards, Rich
lousyreeds1's avatar
lousyreeds1 OP
286 posts
 
Hi Rar1,

Thanks for your response. There has always been a tiny bit of buzz from the amp, but it only got to be a problem when I added the turntable.

I don't think I'm using the term "ground plug" correctly. The previous owner attached a metal nub on the power supply right next to the power cord. I've been running the ground cable from that nub to the turntable.

The turntable's power cord is permanently attached and it is two-pronged. I tried plugging it into the wall, no difference.
zenek_pereszczako7371
1 posts
 
Grado Prestige Gold is unshielded cartridge. Unfortunately with DD turntable always to hear hum.
Sorry for my poor english.
mcfarland
356 posts
 
Zenek is correct. A few years back, Stereophile magazine had an article which described applying sheets of magnetic sheilding to the plinthe of the turntable (I beleive the TT they were sheilding to be a Rega) which solved the problem well, but may not result in the best cosmetic appearance. They also gave information on just where to buy the sheilding material which was sticky on one side. FWIW, I hope this helps. Someone out there may have more info on which issue addressed this problem with Grado cartridges.
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