I have both a Boulder 1108 phono-stage and just got a Weiss DAC. Both have balanced outputs, but I use a NAC 252 which is of course single ended.
When I got the Boulder Chris West made a custom AVO cable that’s a XLR to DIN5 Y-cable. Now that I have the new DAC (replacing a NDX2) I decided to future proof myself and use balanced cables, but with a female XLR/male RCA adapter into the 252 RCA inputs.
Chris West warned me that Weiss states in some manuals (for pro gear) that those adapters must leave Pin 3 open. However, virtually all commercially available adapters short Pin 3 to Pin 1. This is wrong for many applications. Like this…
I asked Weiss why that’s a problem to use a shorted adapter, and Daniel Weiss responded to say,
In that case one of the the output stages is shorted and that causes distortion in the other output stage and also may destroy the shorted stage
I asked Chris West why those pins are always shorted. He says,
The pin-1 to pin-3 connection is required for certain Pro-Audio equipment to “un-balance” the output
Those that have Transformer-Coupled or active "Cross-Coupled Outputs”
Strangely, my searches haven’t turned up a standard adapter that is made with pin-3 left open!…
The ones I have came from Amazon with Pin 3 shorted.
I also looked at my Boulder manual, and it also expects Pin 3 to be left open when using a single-ended cable (Boulder only has fully balanced inputs/outputs). Like this,
So back to that AVO XLR/DIN5 cable Chris made for me. He did it correctly and leaves Pin 3 open, so I can use it safely with either the Boulder phono or Weiss DAC.
My dealer loaned me some balanced cables to try and gave me a set of those single-ended adapters. It took me about 5 minutes to open the adapters and snip away that shorting wire between Pins 1 and 3.
Thanks to Chris West for the heads up. I might not ever have realized it otherwise, so I’m sharing that here now.