Re: Thinking of buying a mesa 50 cal, care to talk me out of it?
The .50 Cal (and the .22 Cal) was Mesa's "low" cost version of the Mark Series amp. They don't have all of the tone switching features of the Mark, but they are not cheap, or a practice amp. They are built for professionals; rugged and durable, with a lot of good features. The biggest fault is that the Rhythm Channel Gain and Tone controls interact with the Lead Channel. This is still an issue for the Mark III amps, but they do have more control than the .50 Cal. The Dual Caliber amps (DC-3, -5, -10) have two completely independent channels. (Even the Mark IV shares R1 and R2 tone controls; you won't find completely independent channels until the Mark V.) Fortunately, the Graphic EQ can be auto-switched with the Lead Channel, and gives you a range of tonal options not found in other amps in this price range.
If you're doing classic rock and blues covers in a weekend warrior tavern band, the .50 Cal head on one of the Mesa 212 C90/EVM Half-Back cabs is darn near a holy grail amp, IMO. The clean tones are above average, the Lead Channel sings like a Boogie should, and the amp takes pedals well. It's just a good straight-ahead rock amp. They do sound good at low volume, but you won't be coming out on the short-end of the stick if you get into volume wars, either...even up against 100-watt half-stacks.
To be honest though, my preference is for the Dual Caliber amps (I have a 4xEL84 DC-3), or the Mark III, IV and V because of the extra control. I have all of these, and love my tones on any one of them. With the Mark IIIs, I have the fully loaded combos, with the EV, Reverb, EQ and Simul-Class. I also have a 200-watt 6x6L6 Coliseum head and Half-Back cab, which is just a glorious sounding amp if I can get the Master Volume above about 2.75. Above 3.75--you'd better be running for cover. On the Full Power setting, notes just explode out of the amp; it so dynamic. The Mark IV has not only more control over the tones in the different channels, but there are a bunch of power amp switching options that can really change the feel of the amp. The V--well, it's just an amazing piece of gear--like having 27 different amps in one box, very organic.
You can go to Mesa's website and download any of their Owner's Manuals for their amps. It's a good thing to have in hand when you are trying out a Mesa amp, as guide for all the various controls and functions.
So considering the limitations of the 25-year old design, the Caliber Series amps have a lot to offer. I certainly would not feel deprived if one were provided on the backline for me.
I hope this helps.
Bill