I used Neutrik XCC XLR-F connector for this flexible LV-61S video cable, it works clean with AES > S/PDIF compatibility for MixPre-D to PMD661 at 24/96.
This AES to SPDIF cable uses a quality 75 ohm coax video cable, converts the 110 ohm AES source into a 75 ohm load impedance with 237 ohms of resistance across pins 2 and 3 within the cables AES's XLR-F connector with the center conductor of coax to pin 2 and shield to pin 1. Terminated the other end of the coax with a 75 ohm RCA connector to match PMD661's S/PDIF input.