Recent content by MisterMojo

Congrats on getting your amp back! I just recently received my 15” DRGX back as well. I agree… they are more than just for heavy tones. A very versatile amp with a bunch of great tones. You’ve got a unicorn there… enjoy it!

Mark IIA’s are wonderful amps! It is a low serial, for sure. A couple of observations: 1.) it looks like it has been modded to remove the Fetron (this is something Mesa has been known to do when servicing IIA’s -if the owner wishes), and, 2.) I suspect that’s not the OG headshell it came in...

Here is what my IIA with Fetron looked like, before Mike B removed it. Looks the same as your pic, to my eye. https://imgur.com/MLZsSG9

Since there is a 12AX7 installed, the switch should be flipped to the 12AX7 position, not the TR1009, as it is in your picture. So, flip it the other way.

Regarding the 60w/100W switch… don’t let that suggest that it’s an H amp. They had limited long chassis faceplates in those days. I’ve had 2 C+ (still have one) D amps that had Full/ 1/2 power on the plate. As far as what to ship them? I only send the chassis. Shipping a 15” combo is $$$. If...

It could be an H (60/100W), which would want to see all 6L6’s. If it’s a D (SimulClass), 6L6 inner and EL34 outer. If you’re not sure what version it is, pull the chassis and check the OT. If it says SimulClass on it, you can put EL34 in outer. Regarding biasing, unless the amp has had a bias...

The set should fetch $5.5-7K in today’s market, depending on condition and tube compliment. If it were a long chassis, maybe $8K.

I’d be concerned about the voltages that the SImulClass would expose them to. You’re looking at around 500PV, and IIRC, WGB are rated at 400PV.

C+’s can be factory, or, upgrades of previous models (IIA>IIC+, IIB>IIC+, IIC>IIC+). Here’s Mesa’s info: https://mesaboogie.zendesk.com/hc/en-us/articles/217026138-Is-my-Mark-II-a-Mark-IIC-

Congrats! Great looking amp! IME, the cleans are primarily what the IIA is about. You can get some nice crunch out of it for late 70’s /early 80’s rock...but it is not a tight, high-gain amp as later versions moved towards. Enjoy... it’s a wonderful amp to have in your fold.

The initials in the top pic... whose are they? https://imgur.com/a/MuaeHxw

If it’s never been serviced, probably a good call to do so. I’ve sent many amps to Mesa, but not a Mark IV. From what I have read and discussed with others about them, it can get a little pricey to service them, particularly a cap job (reportedly in the $700 - 800 range). Best bet is to contact...

I spoke with him (Mike B) a couple weeks back regarding tubes for Coli’s along with other amp service things. Was looking for info on alternative power tubes to STR 415’s. Since Coli’s run such high PV, he recommended JJ 6L6GC STR or TAD 6L6GC STR for current production, STR 415’s (of course)...

Yes, the 7581A’s are quite musical and brutal in it!

Thanks for the update! Running 7581A’s in mine and would have been interested to see if KT88’s would work....