Premium OUTPUT Module

" BLONX " is an output module for balanced transmission of single-ended (unbalanced) audio signals.
If you want to connect the output of the XLR terminal to a single-ended input device, short-circuit the COLD of the XLR terminal to GND (ground). (If pin 2 is HOT, short pins 1 and 3.)
The signal level remains unchanged because the output driver circuitry acts like a transformer.
The output driver op-amp is socketable so you can replace it with your preferred op-amp.
The standard is implemented by Texas Instruments ' NE5532P.

https://www.dotred-audio-designs.com/en/products-top-j/eurorack-modules/blonx