Why do most phono preamps lack XLR input even thought cartridges are naturally balanced?

@atmasphere  thanks for your clarifications. I am using an Ayre P-5xe which has balanced phono inputs.  I was bothered that if one uses the rca inputs to customize resistor loading ( I do not) that the use of one resistor per channel might indicate it was not truly a balanced input. Your explanation of the differential connection clarifies that worry.I have wired my own balanced DIN to XLR phono cables (refusing to pay $600+ for something so simple). Of course pins 2 & 3 are signal, and pin 1 is shield on the xlr ends only. I have a drain wire to the center DIN pin as a drain  connecting to the P-5 ground. Is this correct? I have no hum.

@atmasphere I'll try to have not even a ground but direct balanced all the way from TT to pre

@oldears

DIN to XLR phono cabl e

I thinkg this is what I'm trying to accomplish and this would be "truly balanced" 5 pin DIN from TT to 2x XLR balanced on the pre

luisma31, If it is not grounded at either end, then capacitance to what? To electrically floating object?

@oldears  If its not humming I would not worry, but I suspect there is no need for the 'drain' wire, as the preamp is likely electrically grounded via the ground connection of the AC power cord.

We've been making DIN to XLR phono cables for decades; we just tie pin 3 of the DIN (ground of the arm) to the shield which is pin 1 of both XLRs.