The potential issue is co tami action of the digital bitperfect signal by RF ‘noise’, which can modulate the analogue audio produced in the DAC, with some DACs being more susceptible than others, and, I guess, the nature of the effect also varying from DAC to DAC. Some DACs are extremely good at rejecting the RF, so the resultant effect may be negligible or even inaudible (e.g. Chord Dave) while others very noticeable (e.g. Chird Hugo). I don’t know where the V1 stands. The more susceptible the DAC the more things like network cables, switches and switch power supplies may make s difference.
Thanks for Jude and Innocent_Bystander’s insights. I took the plunge on a Linear Power Supply (Zerozone 5v) for the Raspberry Pi and there is a substantial improvement. It all sounds much more “open” and possibly a little clearer in the treble. That’s despite the old power supply passing the Naim ‘Bitperfect Test’, so I guess the Dac V1 isn’t great at rejecting noise.
It’s now so much better that I’m wondering if an iPurifier would make any more difference (on top of now having a decent power supply), so will look to see if I can demo one.