MarkA and all,
Ok don't get me wrong .. as MarkA says, this box isn't touted to be a B15 clone. However, it was my 1967 B15 I had been playing every day when my Studio 1200 arrived. I also have a 1973 Kustom K200, a 1982 Peavey Mark IV, a 2014 V4b, and a 2014 Ashdown CTM-15.
But it was the B15 I had been playing when the new amp arrived, and so when I started playing the new amp the first thing I did was dial in that sound as closely as possible. And keep in mind .. I'm comparing the B15 through its own cab vs the Studio 1200 through my Ampeg 810. And still I believe I have found a comparable sound!
I'll A/B them this weekend, and also I will mic these up and see if I can post a recording of each to compare.
Anyway, I'm very pleased with the new amp and will post much more detail about my experiences with it later this weekend.
EDIT: By the way, my '67 B15 is all original except I re-capped it with the kit available from Fliptops (just the three electrolytics), and installed a three-prong power cord. It has original Ampeg driver and preamp tubes and (not original, of course) Winged-C 6L6GC power tubes. The speaker is original CTS. The B15 was purchased new by my dad in 1967, and now it belongs to me.