Nagging Ground Issue

garpt

Member
2012-07-20 10:39 pm
Hi all,
Just completed a build of the Elliot P06 phono stage. It sounds terrific. It is being powered by a +/-15VDC hospital-grade power supply, which previously worked great on my Lehmann Black Cube with no issues.
I have all the RCA inputs/ outputs isolated from the case and grounded together. Checked all ground points on the PCB, very strong continuity. No unusual hum issues with my other preamps. When I touch the ground wire, the hum goes away. However, grounding the TT to the ground lug I installed makes no difference. Running a temporary ground wire from the PCB to *Anything* (so far) makes absolutely no difference. The ONLY thing that makes the hum stop is me holding the ground wire.
What should I look for? Any ideas for a permanent (proper) fix would be appreciated!

Thanks.
Gary
 

garpt

Member
2012-07-20 10:39 pm
Hello,
I used the Elliot pcb. I don't think I would trust myself with a breadboard or some such (yet). I have tried every grounding point I can think of and tried removing the ground leg on the power supply as well, although I do not believe this is a ground "loop", per se, because of the way it behaves.

thanks. Gary