My ND5XS2 is connected via DIN to my XS3. A few days ago, I toyed around by also connecting it to another non-Naim amp via RCA interconnects. I just shifted the Output settings whenever I shifted on what amp to use.
One day, I noticed that the sound lost its deep bass when I was playing the ND5XS2 via the XS3. After checking the settings in the Naim App, I noticed that the Output settings was at “DIN + RCA”. When I shifted to “DIN”, the deep bass was back. I further toyed around and also noticed that if I removed the RCA interconnects to the other amp, the sound was good (with deep bass) even if I set the Output settings to either “DIN” or “DIN + RCA”.
Fascinating issue. I sometimes have DIN + RCA outputs running simultaneously where the RCA output feeds a cheap blue tooth transmitter so I can listen to my music on headphones if I’m doing something out of doors, eg mowing the lawn and quality of sound isn’t critical. I always turn off the RCA output when finished, but leave the bluetooth device ( battery powered but turned off,) still plugged in to my NDX. I’ll have to do a comparison later this week, if I get some spare time and will let you know if I get the same effects, although I’ve not previously noticed any lack of bass. With luck someone else will already have investigated this before I get to reply!