If you want to make the Studio 22 less noisy try out a NOS Zaerix 12AX7 tube in V1. If you prefer more headroom a JAN-Philips 5751 tube in V1 might be your choice.
Quote from interview with Randall Smith on Mesa Boogie´s website:
"The basic architecture of the F-50 originated around 1980 and first appeared in our Studio .22 – a great sounding but noisy amp. It’s simpler and more stripped down than the Mark II and the basic arrangement more resembles the...
Soundwise they are definitely in the Mark and F-30/F-50 family. Phantastic clean channel and nice typical Mesa lead channel. The only problem is that you have a quite big volume jump between the 2 channels which makes it a little bit difficult if you play live. On this board someone mentioned a...