The Dynamo MKIII is now available on special order optimized for 300B output tubes instead of the EL 34 which is still standard.
You are both right. The amp can be special ordered with 300B output tubes.
Yes I was considering the 300B version but opted for the EL34.I sold my MKII with the stock tubes keeping my vintage tube complement.Tube rectifier is a 1945 RCA 5AR4GY with hanging filament,power tubes are Genalex KT77's,and signal tubes are Tungsol JAN 6SL7WGT.I have spent hours auditioning several brands of vintage and current production tubes with my MKII and in my opinion for this amp the aforementioned tube complement is the most desirable.Power cable is the Silver Ghost by Mark Tunis and interconnects are Mad Scientist.Will update on my impressions after 100 hours.
The MKII version of that amp seems like a cool thing...I was on the fence between one of those and the Dennis Had amp I actually bought, but Had's amps are somewhat less available or at least rarely available anyway so there's that. Also, I currently prefer the Tung Sol 7581As over anything else I've tried in this amp including the excellent GL KT77s.