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TT Hum

So... I have not noticed this through my speakers, but in headphones; I get a low hum depending on the location of my tonearm. When it’s resting it’s noticeable, but when I move it to cue the hum reduces. Basically, the closer to the center of the platter the less the hum. I have an SL1200, and the power supply is offboard so it shouldn’t be anything under the platter, there is no transformer, etc. It’s not the ground wire from the arm (Jelco SA750D) either. My PSU and everything else is on another shelf, so I can’t see it being interference, and when moving things around it doesn’t change. The only things I can think of could be some kind of weird interference from the pitch fader (that’s the only thing even near the arm's resting position) or I’ve yet to try yet another cart/headshell. Stumped. Thoughts?
au_lait
tomic601's avatar
tomic601
13,022 posts
 
Ha! Good for you. When you say bar i am
assume you mean same leg of the panel ? Is the stereo and dimmer in same vertical row of breakers? You can seek an even lower noise floor by moving all motors and hash producers to the opposite leg of the audio side.
best to you
jim
au_lait OP
353 posts
 
@tomic601 Yes, leg, thanks Jim, pardon my layman’s terms! But now that I think of it, not sure it has to do with what leg. A month ago my front end and amps were on 2 separate lines on the same leg at the panel, but now since moving my front end across the room, I ran another line to that location using a breaker slot on the other leg, but still had the buzz. The hash only cleaned up once the dimmer was gone. Noise floor is pretty damn quiet now, but I’ll try your suggestion too. It’s an old house and the panel is a mess with loads of tandem breakers.
dover
2,262 posts
 
@au_lait

Dimmers are notorious for generating rf noise - I wont have them in the house anywhere.
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