What phono preamps are balanced

Clearaudio Balanced Reference Phono (Dual mono) stage has both balanced inuputs and outputs

Just thought you might be interested in some history:

We introduced the first balanced phono preamp in 1989- the MP-1. It is also fully differential and was the first all tube preamp that was fully differential from input to output. The EQ is handled in differential mode to prevent tube aging from affecting EQ. Although the unit has a line stage it was built with the intention as a stand-alone phono reproducer.

We devised the system of using XLRs with phono cartridges, eliminating the separate grounding wire.

One thing that the high end audio industry does not seem to get is that the balanced line system was created to eliminate interconnect cable problems. Balanced lines allow both long cable lengths without degradation and inexpensive cables to be used, also without degradation. This advantage is not available to single-ended cables. Not all balanced line preamps in high end audio support the balanced line standard, but if they do the difference between a really expensive cable and a really cheap one will be very little. Effectively the hidden cost of the interconnect is removed from the cost of the preamp/volume control system.

How does a balanced phono input work? Don't you need sum and difference from the tonearm/cartridge with some sort of differential driver interface for each channel at each end of the cable?

It is my limited understanding (correct me, someone if I'm wrong) that the signal from any MC cartridge (along with microphones) is already fully balanced. It's also my understanding that most tonearm wires (in the tonearm itself-not external phono cables connecting the arm to a phono pre) have the ground floated, so if you want to connect a MC cartridge/tonearm to a balanced phono input it is simply a matter of having the phono cable properly terminated with the appropriate balanced/XLR connectors. It was that way for me anyway, recently, when I bought an Aqvox 2CI. I'm running fully balanced from turntable right through to my integrated amp through the Aqvox, and in my opinion, it's performance in the balanced mode is superb, and quite a bit better than running it single ended. The Aqvox literature expresses some surprise that balanced configuration is not used more frequently in phono preamps; I think the combination of balanced input/output along with the current mode really provides outstanding performance at a reasonable price.

Which phono preamps have balanced in?