Interesting, as I haven't looked at my 50. But, it is heavy on the bottom end. I remember a demo where PRSh said something like "like the good vintage amps, when you turn it up, you have to turn the bass down and even the mids down." Something pretty close to that. And mine definitely has to have the bass turned down, even at 10:00 on the master. I cured the bottom heavy voicing by hitting it with a Timmy with the bass cut and the treble boosted, and it's a match made in heaven.
That said, if someone offered to trade me a 20 head (which I have hardly ever see, I've seen all combos) and a little cash for my 50 head, I'd do it in a second. The amp sounds great turned up loud. Somebody who gigs could really use this. For me, it sounds it's best at volumes I can rarely ever use.