Following on that, about 2 years ago I had the then new PSA Gain Cell preamp which I found lacking a quality PS. I think the internal PS could be bypassed and a outboard LPS added. Seems right up your alley
Modding the PS Audio Directstream DAC MK1 and MK2
I would like to continue discussing all the mods we have created for these two DAC's as it seems PS Audio is no longer allowing discussions about them on their forum.
For reference here is a link to the closed discussion.
https://forum.psaudio.com/t/modding-the-directstream-dac-mki/2680