@cal3713 One other thought is that you mentioned what 6SN7s you had but you didn't mention where you put them. I have found that any given mixture of 6SN7s will give very different results depending on where the tubes are located in the amps. In my case with the 3.3's, I have some NOS grey glass RCAs in the two most important positions, (back row, left and right). I have a Sylvania GTB in the back center position. This position seems to want a tube with great dynamics, sparkle and air. When I put a third RCA in that position, everything gets kind of sleepy, almost sirupy. But the Sylvania that works so nicely in the center position does not play nicely on the outside positions. In those positions there seems to be a decided lack of smoothness with the Sylvania. In the 4th position out in front, I've tried new production Sophias and Tung-Sols. The TS was better than the Sophia, but Ralph has warned against the new Russian TS tubes elsewhere. The best tube I've tried so far in that position out front is a 1960's RCA GTB. I've got a pair of GE GTA tubes on the way to try in that position. In the end, regardless of tube complement, the M-60s are not going to sound like a 300B SET. I listen to a lot of live orchestral and chamber music, and have a good perspective on what I "should" be hearing. After 18 months with the M-60s, I would argue the M-60s are more faithful to that live music standard, and in my case I really need the extra juice. Ralph and others can offer guidance on how to get the best from the M-60's, but no one can tell you what you ought to prefer. For me, choosing between these amps is a real Sophie's choice. Its going to take a lot to pry either one from my hands. There is no wrong choice between these two options. They both have their own beguiling charm. Some like blue eyed blonds, some like dark eyed brunets. I guess that makes me an audio polygamist.
