I had one of these a few years ago, I sold it to get a .50 caliber, but I never did. A while ago I decided to get one again and so did some research. I actually ended up buying a mark iv instead, but anyway...
As far as I can tell, these are the variations:
-With or without graphic eq, of course.
-The "+" has a lead master volume, otherwise they're pretty much identical. (one more knob on the front) It helps if you're going to channel switch live.
-Look in the back, some have an integrated short reverb inside the chassis, some (later ones?) have an external one on the right side. I would prefer one with the external reverb, if nothing else it's easier to service it if the reverb is not in the way. (and there is more space for switches and knobs in the back!) You could also replace the reverb pan with a longer one if you want.
This is a great amp! I used to love it, and I'm sad I sold it. With the iv, I have no excuse to buy more mesas right now, but if I see one nearby, I'm gonna snatch it! I did a few mods to mine, nothing essential, but I was just starting out in amp electronics so I couldn't help myself... If you know what you're doing:
It would be very easy to incorporate a lead gain, (just replace the 500k resistor to ground following the lead boost with a 1M and put a 1M pot in parallell. This is exactly how the Subway is set up. I would put it in the back.) and the "if only" mid control of the subway amps is actually a classic fender mod; replace the 10k mid pot with a 25k to have an option for more mids. These amps share quite a few design ideas. In the power stage, I installed a triode switch, It made the amp a little bit softer and saggier which was nice at home, just like the iv.
I was planning to put a Celestion neodymion speaker in too, for light weight, and all amps i've tried with them have been fantastic! A bit like how the EV adds clear, loud tone to the iv combo, but without the weight...
Good hunting!
