Re: Mesa Boogie Studio Series.
Well, Mesa actually produced three amps with the Studio moniker, not including the Studio Preamp.
The Studio .22 features a 2XEL84 power section, rated at 22 watts. Its bigger brother is the .50 Caliber, and you'll see these with both 4XEL84 and 2X6L6 power sections. The original Studio .22 amps were designed for players who didn't need the power and tonal versatility of the Mark Series amps. They have fewer switching options; but don't mistake them for budget amps. These are built to the same high quality standards as the other bigger Mesas, and offer a professional quality amp with professional features. However, if you're looking for an amp where you need total control over the RHYTHM and LEAD CHANNELS tone and gain--this might not be the best amp for you. I think these amps work best in a studio situation, where you can tweak it to get a great tone for a clean rhythm track; and then reset the tone controls to overdub your solos with a searing lead voice.
It Studio .22 Plus is basically the same amp, but the preamp now features a LEAD MASTER control to help better balance the channels when used in live music situations. I believe that there were notable upgrades made to the power amp supplies, and to the effects loop. But again, one set of tone controls for both channels.
One really great feature that can be found on both the Studio .22 and the Studio .22 Plus is the optional GRAPHIC EQ. Most Mark Series users will tell you that the GRAPHIC EQ is a very handy feature to have. I have two Mark III amps, and I can't imagine not having this feature.
The final step in the Studio Series is the Studio Caliber .22 DC-2. The Dual Caliber amps now offer independent gains, tones, and master volumes on each channel--plus, an overall MASTER OUTPUT LEVEL. The RHYTHM CHANNEL is said to be from the MARK IV; while the LEAD CHANNEL is based on the Dual Rectifier's LEAD CHANNEL design. The effects loop is now a parallel, rather than a series loop. A switch on the back panel offers the option of SILENT RECORDING, removing the speaker output for those late-nite sessions. There are three more amps in the DC Series: DC-3 (4XEL84--35 watts); DC-5 (2X6L6--50 watts); and the DC-10 (4X6L6--100 watts) I have a DC-3, and it is one of my all-time favorite amps. Alas, no GRAPHIC EQ option on the DC-2.
These are all terrific amps to have around for recording, practice, and even playing out. A lot of jazz players love the warm tones of the Studio amps; and the blues and rock player with find some searing tones when these amps get cranked. Loud enough to hang with a drummer; just don't expect the tight chunka-chunka of a big 100-watt amp and 412 cab. The little 112 combos do have their limitations. Mesa amps typically handle pedals well. If you want to use the Studio set for clean tones, you can always add a good distortion box in front if you need to.
The Peavey Classic 20 and the Classic 30 are generally well-regarded amps; but I think the Mesa Studio amps just smoke the Peaveys. You might pay a little more, but you'll get what you paid for: more professional features, better reliability--a better-built amp that will last lifetime.
The Studio .22 Series amps are long discontinued, but their legacy lives on. The Nomad 45/55/100 are direct descendants of the DC-3/DC-5/DC-10; the F-30 used the popular 2XEL84 power amp section of the DC-2 with a newly-designed preamp. And now, the Mesa Express 5:25 and 5:50 keep that tradition alive. Like their ancestors, these amps may be small; but they are potent--and 100% professional.
I hope that helps. For more info, check out the User's Manuals at
http://mesaboogie.com/Product_Info/product_info.htm
Bill