How to accomodate a balanced only phono stage ?

Just a matter of changing the connectors and having it wired correct on the Balanced side. There is a great reference doc on Rane.com in the Notes area on wiring, I think RANE NOTE 110..It will show how to terminate correctly..

http://www.rane.com/note110.html

I own an Audio Research PH-2 which is fully balanced in to out, and has balanced input connections.
The cartridge on any turntable is OK to use, all you need to do is use a RCA to XLR input adapter. The signal from the cart is fine going into the connector and being connected to the bal input of the Phono stage.
I made a cable with RCAs to XLR as that TT had RCA out on the base of the TT.
If you plan on a permanent installation, you can just replace XLRs on the Phono cable, just leave thee ground XLR pin unconnected, and put the plus and minus wires on those plus, minus XLR pins. No problem.
A few companies have a special adapter (VPI) for balanced phono.

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. I have used an Audioquest cable made that way and it worked great. Any TT setup can run into a balanced phono pre with the right connection.