My $.02 for whatever it’s worth at this point. I like what I’ve heard from this amp from people who actually dial it in. I didn’t mind some of the TGP-audience tones as the Marks can be pretty damn versatile in the right hands. The IIC+, III and IV can do more than just metal. Of course when heavy tones are the main course of the amp you expect to hear them.
Now on to the construction. I ain’t gonna talk shit about the amp because I know Mesa’s build techniques have evolved a bit since the 1980s. And depending on who you talk to, they’ve never been built well. They’ve always been overbuilt and disasters for techs to work on. In the case of this amp I do have some qualms with some build choices. Mainly some of the ribbon cables and molex connectors. I would expect that Mesa is using high quality stuff here as they’ve used it in recent amps pre-Gibson with seemingly no issues related to these things that I’m aware of. At the same time, this is supposed to be a reissue so I would have expected the wiring to be closer to how it was done in 1983/1984 especially for the price paid. Some hardpoint soldering and flying leads wouldn’t have been the of the end world. Hell, folks flipped out when Marshall and reissued with the 1959 with modern wiring and everyone pitched a fit until they got the HW version for a while. For what the cost of this amp is I would have thought more parts of it would have had flying leads like the originals did. Just my thoughts. I know the old amps had pc boards. In fact, Mesa used to etch their own back in the day. At the same time, I expect that current Mesa PC boards are high quality so I don’t see that itself being the issue.
As to the oscillation thing: I don’t have an amp to test but I don’t doubt folks posting it. It is weird that it seems to be happening and users with OGs aren’t having the issues at similar settings despite the feedback from Mesa. Not exactly confidence inspiring. Unfortunately a lot of things can cause parasitic oscillations including something as simple as lead dress. I’m not a tech or the designer on this version.
This isn’t to say I hate the amp. I actually like it a lot! I actually prefer the old Marks that have the multiple volume and cascaded gain controls. I loved how I could fine tune and dial in my IV on the lead channel and I felt like I lost some of that with the V. I want this amp to be a success and hopefully Mesa can get the oscillation stuff sorted instead of doubling down on it. Extreme settings? Yeah I get that. Even my Egnater seminar amp will do that with everything on 10. You’re squeezing a ton of gain out of two preamp tubes without a cold clipper the 2nd gain stage (not counting the loop tube and pi). It’ll oscillate. If it’s not extreme settings though then I question what’s going on with components, board design, etc.