MIke I do like the Grimm PSUs quite a lot. They are dead quiet and since I own KM54s, M221s and a M221B I can use them on multiple microphones. As I mentioned it's a bit of a pain because they use XLR 6 and 7 pin connectors (your choice; the idea being you can avoid units with different voltage settings being plugged into the wrong microphone) so I had to have new cables made because I did not want to be unable to use my old PSUs. Since I record so much quiet material (as I know you do as well Mike) noise floor is critical to me. For most users it would likely be less relevant. Also, I'm really not sure if Bruno was involved in the PSU design, though I share your high opinion of him (I want to hear those Kii speakers bad). However, Eelco Grimm is also a sharp guy and I like his designs as well. The fine fellows at Grace Design turned me on to it and they're damn sharp too!