2. analog
  3. 1186090158

Ground Hum

I need some suggestions eliminating ground hum from my VPI Scoutmaster.

Cart is a Shure V15Vmxr (or whatever it's called)
Tone arm is JMW9 with stock wiring
Preamp is Dynavector P75.

I have tried a few different cables ranging from monster cable to cheap stock audio cables you find with most electronics. Makes no difference. If I touch the tone arm wtih my finger, the hum gets louder. If I touch the gold connectors on the back of the turntable the hum goes away. Touching any other parts of the tonearm output block or the preamp causes hum to get louder. Any suggestions?

A_L
arnold_layne
rwwear
2,867 posts
 
Did you connect the ground wire? If not, it will hum.
arnold_layne OP
141 posts
 
Sorry failed to mention, yes the ground wire is connected. Disconnecting it made it slightly louder.

A_L
cableplex
40 posts
 
Run a ground wire from the dynavector to the tonearm headshell. Does it go away?

Run a ground wire from the headshell to your main preamp. Does it go away?

If it does go away that will tell you at what point the problem is.

Make sure your rca plugs are clean and make good contacts... Most likely you have a break in your ground wire.

Other possible cause could be the pivot point needle bearing is dirty and breaking the ground, or the contacts to your cart are damaged or dirty.
buffyjames
38 posts
 
Try turning the power plug 180 degrees...use a cheater if you need to. Sometimes the hum comes from the 3rd pin - eliminate that for further experimentation.
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