How to accomodate a balanced only phono stage ?

07-31-10: Tdaudio
you don't have to do anything the turntable, it is naturally a balanced signal. Its a matter of physical connection. Some balanced phono preamps have xlr inputs instead of rca connectors which require either an adapter or a custom made interconnect, if that is what is needed/can be used, that has rca on the tt side and xlr on the phono pre side.

It's that simple.

Phono interconnect with RCA connectors + ground wire on the turntable end, and XLR connectors on the phono preamp.

I have a set of these made by Atma-Sphere that work perfectly (Atma-Sphere is differentially balanced, and all phono cartridges are fully balanced, as has been mentioned already).

I think to be truly differential it needs a center-tap 0v.
MC cartridges do not have a center tap so the ground (0v) is floating and does not form part of the signal. The ground path of the tonearm should not be part of the balanced signal - pin 1. The chassis is normally pin 1 with 2 hot and 3 cold OR pin 1 CT (center tap), 2+, 3-.

A mains transformer has a center tap for the 0v which the preamp or amplifier uses as the 0 volt reference and is used as the 0 volt reference for the system.

I don't think anyone produces a Moving coil cartridge which is truly balanced - having a center tap. This would mean having 6 pins.

Dcarol is not on the same page as the folks who have actually used a cart with a balanced phono section. Theory is ok in theory, but in real life this particular theory does not matter. Not having a 0V wire does not matter.
No one needs a 'balancedcart, not a tranny to do it, straight up is perfectly fine.

Just keep in mind that the typical "RCA" cable will have only one conductor for the signal. The "ground" connection in an RCA-terminated cable will typically be carried on the shield that surrounds the "hot" wire. In balanced configuration, there is no "ground". The "hot" wire of an RCA cable fed a balanced signal will carry only the positive half of the signal, and the negative half of the signal will travel on the shield of the cable to the outer ground connection at the RCA plug. Even if you use RCA to XLR adapters, this is the case. Some contend this degrades the signal. Better, IMO, to do a little soldering and change over to XLR, 3-conductor cables all the way.

And Lewm. How does your post add any help to a person trying to understand how to use a balanced input phono?
I guess I have been guilty of info overload, but there ARE NOT three wire in a cart to phono connection. So your advice IN THIS CASE is useless.
Just use the cart wire pos to pos pit in XLR, and grounf to negative pin in XLR, and do not worry about the 0V neutral pin. Thanks you.
(Usually folks can't get an answer, lately too many answers with the wrong info for the question.. Lewm is correct, BUT NOT IN THIS CASE! Jeez..)