I know this isn't a "Diamond amps" thread per say... but I've owned two Diamonds, and sold two Diamonds(Hammersmith and Decada)... still have the cab. If you look at most of their artist/former artists, its the same thing. ( they've kept the 4x12 and moved onto another amplifier) After 2 years of beating my head into the wall over them, this is what I've came to terms with.
They sound EFFN AMAZING, but not all the time. I could walk into the studio and have the most ridiculous tone that evening. Walk out for the night and come back the next day and spend an hour trying to get a useable tone out of it. Seriously some of the best tones I've heard or played by far... just not consistent. I've got friends who play (Heretic and Spitfire) them and their experience seems to be on par with mine. Some nights its amazing and you can't think of ever playing another amp.. Then the other nights come around and boom... you're confused as to why you ever bought a $3000 amp.
Every time I'd try to sell one ,I'd play it and have one of those amazing tone nights and pull the listing.... A few shows or rehearsals later and It be back on the chopping block.. This revolving door of "wtf is going on with my tone" went on for two years and I'm done with the Diamonds for a while. Anyone buying these should try them over a few day period before dropping the dough. With Soldano in on the design it might not be an issue..
Just food for thought