I was with stans explanation until it seems it was all about volume and gain. If we're talking about gain, yes, the 600's are easy to drive loud. I just don't think all the crack love is just hype. neither do I think that it has uncontrolled bass. But then again I'm no expert, and I don't know Mr. Moog, although I love his gear.
before this gets crazy, maybe we should move this conversation to the sound science area.
We all agree the 600's are great cans. at least there is that.