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Update on VPI Prime noise issues

Hi everyone,

Thanks for the advice you all shared on my previous questions about my VPI Prime noise issues.  As an update, the motor noise has quieted down significantly with about 50 hours of play time, so I'm happy to report that the motor noise is no longer a problem.  

However, I am still struggling with the hum that comes from the tonearm wire that connects to the junction box.  I'm using shielded phono cables (Silnote), but apparently the unipivot tonearm is not grounded.  I measured the volume of the hum by turning the volume all the way up on the preamp (Van Alstine Fet Valve) with no record playing.   Obviously I would never listen to anything with the volume pot wide open, but the hum itself measures 75db, which seems excessive to me.  I've tried grounding the tonearm, but that hasn't made any difference.  Even if I'm listening at moderate volumes I'm sure that the noise floor is higher than optimal and that I'm missing out on some low level details.  The dealer suggested trying another pair of phono cables, which I will probably do soon (don't have any on hand).  

My system is the Prime > Manley Chinook > Alstine Fet Valve Pre > Alstine Fet Valve 600R > KEF LS50.

Any more thoughts would be more than welcome.  And Happy Thanksgiving to all.
Best, Scott
smrex13
hwsworkshop
36 posts
 
Shielded cables can mean anything, run a ground wire from the back of the junction box to your phono section, I do that with every cable that does not have pig tails on both ends.
You leave out the most important item, the cartridge!!

Make sure you phono is actually grounded because some of these power distribution cables lift the ground, this is phono, it must be grounded.

You should have no noise at all at normal listening levels.

HW
slaw's avatar
slaw
5,785 posts
 
hwsworkshop,

What do you mean when you say "power distribution cables"?

If a user of your 3D arm is having issues regarding hum or noise of any kind, what do you recommend?

Thank you!
jperry
1,408 posts
 
I recommend having your dealer take care of it, or sending it back to the manufacturer. A turntable should not take 50 hours of run in for the motor to not be noisy. That would indicate a manufacturing defect.
slaw's avatar
slaw
5,785 posts
 
jperry,

I'm not surprised that hwsworkshop did not respond.

It would seem to me that (he) would want to have his post/words explained in a way that all could understand.

If you go to VPI's  forums, you'll see that there are quite a lot of VPI user's who have ongoing issues regarding hum/noise/pops... and when switching the motor on/off.

 Is this a standard that should be ongoing from a 40 year old company? If not, Harry, please just respond to a basic question!

Instead of contacting him directly, I'm currently using the old method of going through my dealer.

We'll see?


smrex13 OP
423 posts
 
Thanks for all the replies.  To respond to some of the questions/suggestions: 

1.  The phono preamp is set at low gain
2.  I have to use shielded phono cables.  Regular ICs cause even more hum at all levels of listening.
3.  I have a ground wire connected from the junction box to the phono preamp (and I even tried a different wire just to be sure).
4.  I have tried two different cartridges with the same hum problem.  
5.  I don't see any obvious breaks in the wires/connectors.

I am going to try a different phono cable to be sure that the problem isn't just a poorly shielded cable.  Keep y'all posted.

Thanks, Scott 
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