I have had 2 of these in the UK. Amps both work fine with my active basses, but with passive bass or my active basses switched to passive, there is a "Hum" when the guitar volume control is backed off from full. Mesa say they couldn't recreate the problem with the first amp when it was sent back to them. The USA store say they did have the problem on the amp when it was sent back to them, and they sent it back to Mesa. The store tested a second amp which was fine, but when I tried that in the UK, it had the same "Hum" problem as the original.
I have to say apart from the "Hum" issue, the amp is great and because I don't use passive mode on my basses, it has become my first call amp...D800 is now spare and or used for louder gigs.
All cables/mains checked.....the Hum issue doesn't happen with my D800 or D800+ di.
D800+ di fed to the aux in on the D350 is also fine, suggesting a D350 input/preamp problem.
Hum happens with my 3 Sadowsky's in passive mode. Also my Xotic jazz bass. Also happens with other basses I've tried..Fender Jazz Bass, Maruszczyk Jake PJ and a Gibson jazz guitar.
Anybody else using one of these in Europe 230V/50hz?