@saxaudio1 One of the founders of BAT was one of our customers. He had our balanced preamp called the MP-1. It had the first and for a long time the only balanced line phono section in it. Since the cartridge is a naturally balanced source it seemed the thing to do.
We went balanced so that the interconnect cables would not make such a big difference in the system as we were hearing with single-ended cables. The phono section seemed the place where you really wanted to get it right. To that end we supported the balanced standard, also known as AES48 (Audio Engineering Society file 48). A phono cartridge driving our phono section supports that standard.
It didn't occur to us that other manufacturers might not support the standard but that is what we've been seeing. That is why there is controversy about whether balanced operation sounds better. IMO if its set up right, it sounds better and no going back.
Because building a phono section whose output supported the standard meant making as much circuitry as our entire full function preamp has already, we've never offered a phono section separately. I have real difficulty believing an outboard phono system can actually sound better; this is mostly because the the interconnect required between the phono section and the line stage. Since all the outboard phono sections I've seen don't support the standard, then it can be expected that there will be a degradation on account of the interconnects despite being balanced.
AES48 assures that everything goes right- no ground loops, little or no cable interaction (although with a phono cartridge it still helps to use a low capacitance cable).