I had the 6505mh and it was just ok.IMO Peavey crammed too many features in a small head,yeah the features are nice,but the head I had at 1st always ran so hot when you touched the front panel to make adjustments it damn near burn your fingers,so I sent it back and got another one and same thing if not worse,so I called Peavey and they said a quick bias adjust will fix that,so I checked bias with my tube probes,and 1 tube was at 31mv and the other at 22mv,so I just put in a new pair of matched JJ's and biased at 27mv where it sounded the best and it still ran hot,any colder and the amp sounded so thin and sterile it was ridiculous,and the bias drifted so much,even with a new Peavey installed bias adjust pot I sold it Thank God! What a nightmare! Look on Peavey forum for more 6505mh horror stories! Sorry Peavey that amp head sucked!! Sorry for intruding on your thread !!