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Topic: Bye-bye turntable ground loop! (Read 3781 times) previous topic - next topic

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Bye-bye turntable ground loop!
Just killed a major ground loop affecting my turntable (Technics SL-D3). As it turned out, there is a little metal tab that goes from the cartridge casing to the Right-Negative terminal of the cartridge output (Shure M-95 ED).  The problem with having that way is that the cartridge housing provides another path to ground by means of the screws/headshell/tonearm.

After I pulled that tab out, all the hum went away (which was annoyingly greater in the right channel), and now I'm left with just white noise at about -80dB RMS in both channels.

Life is good...
godzilla525

  • fewtch
  • [*][*][*][*][*]
Bye-bye turntable ground loop!
Reply #1
My problem has been with RFI, but it's an issue related to the preamp, not the turntable.  I'm trying to get my hands on a Technics SU-C01 preamp, which I'm guessing will solve all my problems (including crappy RIAA response from cheap phono stages) .
Bring back dynamic range... www.loudnessrace.net

Bye-bye turntable ground loop!
Reply #2
I went ahead and threw that out there in case someone else runs into a similar problem.

I guess Shure expects people to use plastic tonearms. 

Right now I'm using the preamp in my receiver, which matches the +4dBu input setting of my soundcard perfectly, but I'll probably have to throw a monkey wrench into the perfect level-matching and pick up a new cartridge and possibly make/buy a better preamp, as I am getting what sounds like too much THD.

I've taken better care in aligning the cartridge and stylus, the result of which is no more vinyl dust on the stylus at all. :eek:
godzilla525

  • fewtch
  • [*][*][*][*][*]
Bye-bye turntable ground loop!
Reply #3
Quote
Originally posted by godzilla525
I went ahead and threw that out there in case someone else runs into a similar problem.

Oh come on, admit it... you just want to discuss your equipment, and/or turntables & analog gear...

(i don't blame you  )
Bring back dynamic range... www.loudnessrace.net

Bye-bye turntable ground loop!
Reply #4
Well... yeah.  I finally cleaned off a spot on my desk and got around to hooking everything up.  I also discovered that none of the 3rd party software that came with my sound card works at 24/96 even though it's supposed to.  The only thing that works is Cool Edit--and only in some wacky 32-bit floating-point format.
godzilla525

  • macdaddy
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Bye-bye turntable ground loop!
Reply #5
related link and quite a good read...

  • JonPike
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Bye-bye turntable ground loop!
Reply #6
Quote
Originally posted by macdaddy
related link and quite a good read...


Wow..  quite a piece!  And,  a ton of links..  One for the bookmark file!