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Ground loop hum

My technics turntable developed a ground loop hum when I got a new preamp Rogue RP7 and power amp Aesthetix Atlas.  I had a ground wire connected to the turntable and grounded it to each, one after the other when the first had no effect. Neither did the second grounding. It has been suggested I ground it to both at the same time which I haven’t tried yet. Any other suggestions?  I am running the system from two dedicated 20 amp lines. Running Vandersteen Quatro wood ct speakers.  Thanks in advance. 

kavakat1
panzrwagn's avatar
panzrwagn
659 posts
 

@jea48  You clearly understand what causes hum, now its a matter of where and how. You’re doing all the right things. That the hum is controlled by the volume control and only on the phono input narrows it down a lot.

@kavakat1 One more variable though, what kind of cartridge is being used? 

kavakat1 OP
141 posts
 

Using MC cartridge

kavakat1 OP
141 posts
 

Same cart as with the NAD AMP

kavakat1 OP
141 posts
 

Something to report. I unplug my phonograph power plug and the hum is still there. What’s that mean. Will move phono to line 3 to see. It’s presently on line 2 and cd is on line 3. Too much fun. 

erik_squires
16,924 posts
 

I’m late here.  First try moving everything to the same outlet.  This will ensure your "ground loop" isn’t really imbalanced voltages causing imbalanced center tapped ground differences. 

Unplug anything metallic besides your audio.  Ethernet is OK, but coax is not, and USB is not. 

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