Hi Brian:
I happen to have some experience with just that amp. Back in the early 90's I lived in NYC (actually, I lived there all my life until 2 years ago when a 3rd child forced a move to NJ for more room) and I wanted to buy a MK IV. I had a friend who actually purchased one of the first MK IV hardwood combos directly from Mesa, back when you could do that. I went to both Sam Ash & Manny's and tried to get my amp. In both cases, the folks at those stores knew considerably less about the amp than I did *AND* at both places the hardwood combos that they pulled from the stock rooms were damaged (one, at Manny's, had the hardwood cab's dovetail joints seperating!). So, in desperation, I called Mesa/Boogie. They were very nice and sent me to their East Coast Artist Rep in Rockaway Beach or Far Rockaway (I'm a Manhattanite, so it's all the same to me). I got a friend of mine to drive my brother and me out there on a winter afternoon (by the time we headed back we were in the middle of a *MAJOR* snowstorm) and we met the Boogie Rep, a guy named Mark Snyder (I belive he went on to be Vernon Reid's guitar tech and now builds big "Racks"). Well, this guy had a whole storeroom filled with boogie Chassis and cabs. He let me pick both my chassis and cabinet and choose the speaker and then he put the chassis in the cabinet and mounted the speaker (a Celestion 90w Black Shadow) as I watched! My cab doesn't even have casters, just big rubber feet (bummer!). Anyway, I found the Celestion to be a slightly warmer speaker and that is why I chose it. As I understand it, the EV is a 200w speaker and tends to remain very "tight"; I prefer the "looser" sound of the celestion. One other thing of interest is that he had a couple of monster rack systems there and in one he had 2 different MK IV chassis. He let me check it out and pointed out that there were 2 distinct lead voicings available for the MK IV. I don't recall what he said the actual difference was, ( I *THINK* he said that one had a lead voicing akin to the MK IIC amp, whereas the other was a newer more "modern/high-gain" setting; this was right around the time that the Dual Rectifier came out and I think that the lead channel in my amp is supposed to be a little closer to the Rectifier lead sound, but, truth be told, I don't remember), but I chose the higher-gain version. I can't remember now whether or not the version I chose was the less-common, "custom" version, but I as far as I know, Mesa never mentioned that option in any of their ads, so perhaps it was only available to "recording" artists or something. Anyway, that's my experience.
Cheers,
David in NJ
