2. analog
  3. 159402-146077

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

Showing 2 responses by chakster

chakster's avatar
chakster
6,144 posts
 
@au_lait

-What is the cartridge?

-If you have a few different cartridges do you have a hum with all of them?

-Any proper platter mat on your Technics SL1200 or just a felt slipmat or stock rubber mat ?

-Hum is noticeable on normal level or on high volume only ?

-Can you hear the hum only using your headphones and its amp or you can hear it in the speakers?

P.S. First thing to check is ground wire from your Jelco tonearm to your phono stage. You can disconnect it and try again to see is the hum is gone or increased. You have to check headshell leadwires and headshell connection (lock) with the arm. DIN connection of the phono cable to the tonearm base. This is basics. Put some nice metal mat on Technics platter and try again.




chakster's avatar
chakster
6,144 posts
 
I don’t think it has anything to do with the stylus, you’d better try one of your mats on the platter to block EMI effect. It can be tonearm internal wires in the arm tube or something related to the tonearm. It is true that some people having problem with Grado MI cartridges hum on Technics turntable, but not with Nagaoka MM. Anyway try different cartridge first and if the problem is there with another cartridge than it’s definitely turntable or tonearm.
More to discover