Is there anyone out there who owns a vintage example of each of these? I'd really appreciate a description of the difference in sound. I understand the technical differences (higher B+ in Brown Princeton, 12ax7 vs 6at6 preamp, tremolo in Brown Princeton, etc). I've read through many threads comparing the two amps and most people simply say "they're the same but one has tremolo", "one has higher B+", "the same but with different preamp tubes", or just list the technical differences. There aren't many descriptions of any tonal, headroom, or character differences between the two and I'm curious: What are the sound differences? If you put a 6av6 tube (approximately half a 12ax7) in the preamp of a tweed Harvard are you getting the sound of a Brown Princeton sans the tremolo, or is the lower B+ changing the character of the amp a lot? I have a tweed Harvard clone and do get a dirtier sound out of it when I plug in a 6av6 for the 6at6. Am I getting the Brown Princeton sound just by swapping the preamp tube? The Harvard is such a killer amp and I find myself asking how it could get any better than this? But then I see tons of threads praising the Brown Princeton and I wonder, maybe it can?