2. analog
  3. 1308313851

RF Interferenece and hum on tonearm

As much as I enjoy NPR, I'm having a hard time enjoying it when I use my Denon DP 75 DD turntable, Lustre GST1, and Grado Signature Platinum cartridge. I am running three grounds from the TT system to the preamp:tonearm shield, TT motor, tonearm mounting. The RF only occurs at moderate to high volumes and increases dramatically if I touch the tonearm wand. Touching any other part of the tonearm does not increase the noise.

In addition to the RF interference, I have a hum problem.

The CD player and TT are plugged into an APC power filter. The hum decreased as I added the ground wires. Unplugging the CD, plugging the TT directly into the wall, moving the wires did not change the hum or RF. Moving the tonearm closer to the motor increases th
128x128garibaldi
swampwalker's avatar
swampwalker
5,138 posts
 
Do you have another cart you can swap in? Grados are known as being particularly sensitive to picking up noise and hum.
hifihvn
943 posts
 
It sounds like the tonearm ground has a poor, or broken connection somewhere, is the most likely thing I can think of.Try wrapping some soft wire strands (after stripping 2-3 inches of insulation off it)around the arm, with enough length of wire to ground the other end. Some flexible light gauge stranded wire. Maybe just tape over the strands of wire on the arm wand so it doesn't cause any scratches on it. If this works, that would verify that there may be a poor connection on the arm ground, maybe where its out of sight.
hifihvn
943 posts
 
Swampwalker was posting while I was, and got his in first. I forgot about Grado having this problem, but it still could be the ground for the arm.
More to discover