Nagging Ground Issue

garpt · 15th March 2013, 06:23 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

epicyclic · 15th March 2013, 09:24 PM

Hi Gary

have you made your own pcb or used the Elliot .

garpt · 15th March 2013, 09:29 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

Rundmaus · 15th March 2013, 09:29 PM

Quote:

Originally Posted by garpt

Hi all,
The ONLY thing that makes the hum stop is me holding the ground wire.
Any ideas for a permanent (proper) fix would be appreciated!

A nice piercing with a ground lug and a long cable would do....

*SCNR*

Rundmaus

garpt · 15th March 2013, 09:34 PM

Quote:

Originally Posted by Rundmaus

A nice piercing with a ground lug and a long cable would do....

*SCNR*

Rundmaus

It would have to be long enough for me to reach the kitchen fridge to grab another cold one.....

Rundmaus · 15th March 2013, 10:15 PM

... I am allowed to jest - having a nagging grounding/noise issue with my own circuit as well...

See: Locating hum source

Andreas

garpt · 16th March 2013, 12:31 AM

Quote:

Originally Posted by Rundmaus

... I am allowed to jest - having a nagging grounding/noise issue with my own circuit as well...

See: Locating hum source

Andreas

There's nothing (almost) more frustrating for a DIY'er at my level, anyway.
Thanks for the link. I will explore some more....

Gary

15th March 2013, 06:23 PM	#1
garpt diyAudio Member Join Date: Jul 2012	Nagging Ground Issue 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

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15th March 2013, 09:24 PM	#2
epicyclic diyAudio Member Join Date: Jan 2012	Hi Gary have you made your own pcb or used the Elliot .

15th March 2013, 09:29 PM	#3
garpt diyAudio Member Join Date: Jul 2012	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

15th March 2013, 10:15 PM	#6
Rundmaus diyAudio Member Join Date: Aug 2005	... I am allowed to jest - having a nagging grounding/noise issue with my own circuit as well... See: Locating hum source Andreas