Mesa Boogie Mark III / IIIC+ with 105PT & STR-415/416 Imbuia
Posted on March 29, 2019 by Scott French
If you're looking for the best possible Mark III then you can stop here, you've found it. This is a 1985 Mesa Boogie Mark III. It's an early no-stripe version released just after the Mark IIC+, and being a transition model they share a few common elements. The 105 power transformer and heavier faceplate are carried over from the IIC+. This is a DRG, meaning Simul-class, Reverb, and Graphic EQ options. It also has an Electro Voice EVM-12L which was the premium speaker upgrade in 1985.
The hardwood combo cab is Imbuia and beautiful with with a nice wicker grill to match. Far from perfect, but it presents pretty well. FYI, this was an original hardwood amp, but I liked this 1989 cab better than the original 1985 Imbuia cab, so I "upgraded" to this cab and speaker.
In 2017 this amp was sent back to the Mesa factory for service and upgrades. Pretty much every available option was added... the III+/IIIC+/IIC+ circuit upgrade, R2 volume addition, reverb fix, as well as a pentode/triode switch. The amp also had a general service and cap job.
In the time since that service I've also tracked down these vintage STR-415 6L6 and STR-416 EL34 power tubes. Anyone that's looked knows the 415s are hard to find, but the 416s are basically impossible. You have to get really lucky or dig like crazy (like I have to a silly extent).
So to summarize, this was already the best Mark III model (DRG) with the nicest cabinet (Imbuia & Wicker) and the best speaker (EVM-12L) and the best tubes (STR-415/416s) but has also been recently factory serviced with pretty much every upgrade available (save for IIC++ which I'm not a fan of).