I have heard a Plinius SA 100 drive Diapasons right in Shahinian's factory with no hum - so I know it's possible. However, since I don't know myself if it's a unit to unit thing or otherwise, for the money you'd spend you might be better off getting the AVA Ultra 550. It can drive these speakers with no hum and sound also very nice.
Original Plinius Sa-100 series amps for Shahinians
I have read in the archives much about the hum problem of these amps. I am looking for an amp for Shahinian Diapasons. Apparently the hum problem was fixed with the Mk3's use of two power transformers. There happens to be a Mk2 available right now on the GON. How bad was this problem and how expensive would it be to have it upgraded to the MK3 version if it was needed? Were there any other sonic differences between the Mk2 and Mk 3?