balanced output VPI

To be honest though, I would probably just try it with a regular interconnect and see if it shows any promise.

No, you won't have to modify the box. Again, it's all in the manual.

@Riffer,

When I look at the manual:

http://www.vpiindustries.com/manuals/vpi-scout.pdf

I find nothing about how the juctions box is wired.

I am no expert, but here is what I understand. Sorry if this is too obvious and too long. Much of it is just repeating what has been said above. But, here goes anyway.

A cartridge has a + and a - lead, with no ground. My guess on the VPI is that the + goes to the center of the RCA output jack and the - goes to the sleeve of the RCA output jack. My guess is that the switch on RCA input on your phonostage simply lets the sleeve float (balanced) or ties it to ground (unbalanced). In that case, a standard RCA should work for balanced, with Atmasphere's cavity that the shield of the wire is now carrying a signal so can be sensitive to noise.

A wire with 2 conductors and an outside shield is a better option. It sounds like you may already have that type of cable, since you say you have a separate clamp for ground on the cable. If that is the case, you may be all set. Just connect the grounds on your cable to the grounds on the VPI and RCM and you may be all set. But you cable may also just have 1 conductor and shield with an extra clamp to connect the ground screw to the shield. You can check with a multi-meter (see below).

To be sure, I would call VPI and ask them specifically how the RCA outputs are wired. I would contact RCM and ask them what the switch does.

If you can use a multi-meter, you can test what the switch on the RCM does. Just check for continuity from the ground post to the outer sleeve of the RCA input with the switch in both positions, with the unit unpluged and nothing connected to the RCA of course. If it just connects the outer sleeve to ground when in unbalanced mode , there should be continuity.

You can also use the meter to check the wiring of your interlink and be sure that the center, sleeve and clamp are all independent.

You can get a continuity test or cheap multi-meter for 10 bucks if you do not have one.

I have read that you should be careful with a multi-meter on the VPI side, since the current from the meter may damage the cartridge. I have no idea if this is true or not, but I would err on the side of caution. If you disconnect the cartridge leads, then you could test how the leads on the shell connect to the RCAs.

My nexts steps would be to contact VPI and RCM and also check to see how your cable is wired.

My guess is your are all set, but I would check with VPI and RCM just to be sure.

The Ayre phonostage manual gives a good description of connecting a RCA to a XLR. You are not using an XLR, but the diagrams are good for understand the wiring. At least I found them useful when trying to figure this out originally.

AyreP5xe Manual

Mordante, there's your problem; you are looking at the wrong manual.

You need to look at the RCM Prelude Sensor phono manual, not the VPI manual for the wiring diagram.