Rb301 Ground Wire Mod

[tiller]

Interesting idea wobbleu... I have some copper tape around here somewhere I could try. Although I'd rather not modify the cartridge if at all possible.

I've managed to get the hum a little quieter by unplugging practically all of my other equipment. Honestly, I am amazed at how susceptible the cartridge is to other equipment as I figure my setup is no different than most.

Just some other tidbits of info that could maybe help out:

- The hum is much stronger on the left channel.
- The cartridge picks up a significant amount of interference from the motor when the TT is running. Do people have this problem with other carts?
- Disconnecting the cartridge and shorting the tonearm wires (L- to L+, R- to R+) results in practically no hum. Using an older cartridge (Shure M91ed) results in practically no hum.
- The only thing that truly makes a difference is physically moving the turntable. I hooked up a very long set of phono leads, cranked the volume, and walked around my room with the turntable. I managed to find a place where it was quietest, but unfortunately that place is not practical for setup purposes.

Anyway, I am moving in a couple of months so I am tempted to try and ignore the noise and hope that it won't be so bad in my new place.

Thanks for the input folks!

Adam

[tiller]

Hi folks,

I felt it necessary to update this rather old thread of mine. I have since moved into a new apartment. I hooked up my deck and preamp and everything and ... no hum! (Or at least it is reduced so much so as to not be objectionable).

Anyway, I think this further reinforces the theory of the Exact picking up stray EMI in my old place. Now, whether or not the Exact is particularly sensitive to this or if my old apartment was really bad for EMI, I'll never know. Either way, I'm happy.

Thanks for the all the comments and help folks!

Cheers,
Adam

P.S. The cartridge still picks up EMI from the motor however. Evident in the increase in hum as the cartridge approaches the spindle.

[Les_Creative_Edge]

Bringing this topic forward, if I may add my situation.

I have a P3-24 and once connected found that I too have a buzzing sound. I made sure the connections were good and then began to run things down. I disconnected all components accept my receiver, my 2 channel power amp which drives my main left/rights and the P3-24 as well as the TT-PSU. Using the receiver's phono section I get buzzing sound ( it also came through my outboard Cambridge 640p phono pre. Turning on the TT-PSU increased this buzzing. I ran a ground wire from the TT-PSU chassis screw to a grounding post on my receiver. The buzzing reduced but did not go away. Next, I ran a length of wire from the receiver's ground post and TOUCHED the counter weight on the RB301 arm. The buzz went virtually silent upon doing this. This leads me to believe that the major ground issue is in my tonearm. I'm also thinking then about running a separate ground wire from the RB301. I did this with out to much difficulty on a RB250 arm I once had in a DIY turntable set up. I suspect the wiring for the RB301 will be similar.

ANY THOUGHTS!?! Thanks.

[Les_Creative_Edge]

To add to my previous post.

When I turn on the turntable and set my receiver to phono. I hear the faint buzz sound that again is virtually removed with touching a ground wire to the RB301 counterweight. But sans doing that the buzz is there. When I touch the tonearm the buzz increases meaning that I myself by touching the arm am feeding a signal into it. If I am thinking correctly I believe that modifying the ground wire from its soldered point into the left channel negative lead and run it as a separate wire will greatly reduce or eliminate this hum. Am I correct?