Hum with the Avenger with a LOMC ...
 

McIntosh C200 w/ Ortofon SUT
VPI Avenger w/ 12” 3D arm and Ortofon Per Windfield

Have tried shielded, triple shielded, twisted pair, and twisted twisted pair interconnects between the VPI and the C200 MC Inputs to no avail. I measure 2mVAC between the ground studs of the C200 and the JWM arm box with my Fluke 87 with a ground lead connected between pre and VPI and over 1VAC with it disconnected. Connecting a ground lead between the C200 and VPI has no bearing on the noise - its the same with or without it. I can:

Unplug RCAs from the tt only and have no noise
Unplug the Lemo connector on the JWM box and have no noise
Ground the shield of the RCAs at the JWM box and make the noise worse
Touch the ground lead to various parts of the arm mount to no avail
Connect the ground lead to the ground stud on the JWM box and do the same with a 2nd ground lead from the box to no avail.

Both units are plugged into the same source of power.

The combo sounds sweet but I can’t really give it any volume to speak of. Suggestions?

Wow - you have tried everything I would have tried. What happens when you pull the Lemo connector?

Possibly bad cartridge; contact the source.

The hum is gone completely upon disconnecting the Lemo connector ...

So that tells you the hum is coming from the cartridge and/or internal arm wiring, correct?

This is what I would check out next.

Measure the resistance from the center pin to sleeve on each RCA jack. You should see somewhere between 5 and 10 ohms since the Winfield is an MC cart.

If that is ok then measure from the RCA sleeves to each other and to the ground post on the turntable. Those should measure open. Measure the center pins of both the rca’s. They should measure open.

If all of the above is true then you know the arm/cartridge is wired correctly.

Tom

Is the setup new, or you’ve had it for a while and the noise recently developed, i.e. did the noise appear with an equipment change?

Also do you have another cartridge you can try?

Thanks for the input! I have work to do. I'll report back.

I previously had a Dynavector DV10x5 on this arm. It hummed a bit as well, but at a much higher setting on the volume control (at "70" it was audible whereas this is audible at "40"). I never thought much of it.

Have you tried without the SUT? Volume will be way down for a similar setting, but should provide an indication if it is a bad match to the C200.

Found the problem. The SUT was damaged in shipping... I had no idea as I never used it. At this point I'm unsure what I may do ...

Is this an external sut or the one in the preamp?