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Yet another need help with a ground hum thread

Hi all I am hoping that someone can help me out here. My sources are split between the living room and a small bedroom. I have a pair of Mackie monitors and a pair of SVS sb1000’s in the living room with a Schiit passive preamp and a Schiit mani DAC. I have my Technics SL 1200 in another room with a Icon Audio ps1 mkii. The turntable is in the other room to solve a feedback issue I was having. Upon first setting the turntable and preamp up I got an  immediate  ground hum. I tried the ground lift on the preamp and it didn’t help. The only thing that seemed to help was running an extension cord to the same outlet everything else was plugged into. I lived like this for a while until I could install an outlet on the same circuit thinking that would help. The circuit is run from the panel to a junction box where it splits to go to the living room and the room where the turntable and preamp are. Upon hookup the hum was back. The hum is present even when the preamp is not turned on. No idea what is going on with that. I have a super cheep Pyle phono preamp with a wallwart power supply I keep as a spare. With the Pyle hooked up no hum just a very slight buzz which I assume is the power supply.  My question after all of that is does anyone have any thoughts on how to eliminate the hum with the Icon Audio preamp? Do you think it is a issue with it being a tube pre. Would a solid state pre have the same problem?
wilson667

Showing 2 responses by erik_squires

erik_squires
16,592 posts
 
I'm not worried about how well it's shielded. I'm worried that the guage of the shield is too thin. What happens if you shorten the RCA cables to 1 meter, and lengthen the power cable?

That's the kind of diagnostic I was hoping for. :)


But have fun, I've helped all I can.
erik_squires
16,592 posts
 
I think the issue you are having has to do with the long RCA cables having an unexpectedly high resistance due to the length.

Try this.  Move the turntable into the same location as the preamp, but use the SAME RCA cables.

If this still causes your problem, then the issue is you need interconnects with beefier shields.
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