There are pros and cons when it comes to comparing amps of each generation. Sometimes some may not bond with the next best thing and favor what was made in the past more than the current offering. At least their first attempt on a IIC+ reissue was not a total flop. JP2C is decent for what it is and what it is not. First Mesa I got my hands on that had midi control. The second was the TC50, why I bought the TC100 was thinking it would rival the RA100 but it did not. Once you figure out what tubes to use in the RA it is hard to beat. Still, the TC series are cool amps. Mark VII being the second gen to get Midi was the reason for me to end up with two of them. I can control both with one footswitch along with a midi cable connecting the two amps. (I swapped the faceplate I ordered for the JP2C to match the V212 cab so that explains why there is a JP2C badge in the lower right corner of the amp on the right).
The Mark V90 becomes a bit more difficult to manage that without extra gear (two midi-matrix units and a midi controller). It is not impossible but not straight forward.
I would not personally choose an amp based on my opinion or video content. Best to actually use it in person and listen for yourself. That may sound easier than it is since not many places are stocking the Mark V90 since the Mark VII rolled out. You may be able to find a used one. The Mark V90 is still in production based on the Mesa website. I was curious to see how long it will remain in production now that the next gen has been out for at least a year. If you are looking to buy new, sit down with the JP2C for a while. If they have one in the showroom sometime next year the IIC+ Reissue may be available to test drive. It all depends on what you are after in terms of features and options. the Badlander 100W is a beast in its own way and from what I hear about the 50W that too can deliver.
I purposely left out the pros and cons of each as there was no point in doing that. What matters most to the buyer is the sound quality and features and options that make it easy to use. The Mark V90 is different than the Mark VII. Chose which you like best. Not sure what changes if any Mesa did to the Mark V90 over the years after I got mine. I do know the transformers have changed over to Schumacker since the supplier that made the transformers decided to close for good during or after the pandemic.
They are tube amps after all. Power tube replacements is rather a simple task. No disassembly required except for removal of the tube cage. When it comes to the preamp tubes, that is where things can be challenging. The Mark V 90 did have some challenges to gaining access to the preamp tubes, more so a pain in the head format. Mesa may have amended their design of the V head for ease of preamp tube access. You can get to them after you take out the power tubes though but it is tight. The tube shields are one thing and trying to get them back on is frustrating. Then trying to seat the preamp tubes by feel is another task. Here are the fun pictures of to look at.
I still have my 2012 Mark V90, it was a head when I got it but thought I could just convert it to a combo with the idea of using an EVM12L Black Label speaker. I recently retired it. Just never bonded with the amp. The amp on the right is the Mark VII when I first got it before I transferred the JP2C faceplate.
The Mark VII is much like the JP2C and the Triple Crown, it is not necessary to use the footswitch if you do not mind switching the mini toggles on the front panel. The Mark V90 on the other hand is not so user friendly. Instead, there are rotary controls on the back to select channels and such. The Mark V90 is a medium width amp often referred to as the "wide body" which was the term used when the Mark IVB came out since they made the chassis a bit longer to fit all of the controls and such.
Back panel of the Mark V90. The Mark V combo never came with an EV speaker, they use the MC90 black shadow speaker which is quite different. I believe the last time Mesa used EVM12L was with the Mark IVA combo before they changed over to the wide body format. That seems to be standard issue with the combo amps like the Mark V, Mark VII and JP2C combos. I just had a preference for the EVM12L speaker. I did have to add a brace to the rear panel as it vibrated like hell from the EV speaker. The power transformer is not very large and I think it is the same one used on the Dual Rectifier Roadster. The small silver transformer is the power choke, the power transformer is just behind it. It is a decent size. Still a decent amp though. Perhaps not so compatible with the EV speaker as I hoped it would be.
The size of the power transformer is easier to see in this image. It is on the left. I had the chassis out to swap preamp tubes and to replace the speaker in the cabinet.
I had other reasons why I converted the head to a combo. Getting access to the preamp tubes was a pain. Always had to remove the power tubes and try to reach around the output transformer to get to the V1 tube. The head did have a removable face plate but that did not make access of the preamp tubes any easier, the panel it was mounted too was solid, no cutout to gain access. That is what I found with mine anyways. Not sure if that changed after 2012. I found it much easier to just pull the chassis out. I took off the tube shields as I was tube rolling the amp. I would not use the amp without the shields as it keeps the preamp tubes secure and may help to limit vibration.
If you want to see the Mark V90 Guts, here is what it looks like.
So, when it comes to the other two power houses in the same price range for a new amp, there are some major changes from the Mark V90 when comparing to the Mark VII and the JP2C. They may be smaller in size but more to the traditional size before Mesa made the widebody format. The Mark IVB was not the first as there were some long chassis formats of the IIC+ and III more fitting of the Coliseum format KRG or 180W if you like. That goes back to the IIB+ up to the Mark III platforms.
Here is the Mark VII next to the JP2C. The Mark VII is the one on the left. The power transformers may look to be different size but they measure about the same. There is a difference in tone between a 90W Simul-Class and a 100W Class AB amp. the Class AB will have a darker voice to it and the Simul-Class will be a bit brighter but not by much. Despite the 90W vs 100W, they are both respectable power house amps that are essentially equivalent in output power peaking around 145W. Same for the Mark V90. Note that you will not experience the full potential of these amps in combo form unless you add in some external cabs. Sure you can do that. They work just fine if you unplug the combo speaker and drive a 412 cab if you so desire. The disadvantage of the combo vs the head is the extra weight. If your intention is to make use of other cabs, you may want to reconsider which format works best for you.
Gaining access to the preamp tubes is quite simple but may be a tight fit unless you place the amp on its side for ease of access. Remove the front panel and there they are. I did try preamp tube access from the back of the amp with the power tubes removed, not possible with adult sized hands. The cutout on the inner board is much larger than that of the JP2C but both provide access to the preamp tubes.
This may be for the standard production version of the JP2C. The limited edition signature model did not have a removable front plate. Chassis extraction method was probably the only practice to gain access to the preamp tubes. Trying to get your hands around the fan and the small transformers was not practical. The Chassis can be removed after you get the power tubes out. JP2C and Mark VII. With the Mark V90 and many other Mesa amps, I can get it out without the need to remove the power tubes. Getting the JP2C or Mark VII chassis back in is a pain, more so getting the reverb and the power cable back in place. and needs to be done before you get the chassis into its final position. I have gut shots of both as well. Chassis is a bit tighter to fit it all in, so there are several layers of boards, and the power tube board is not visible.
Gut shot of the Mark VII:
And here is the JP2C just for kicks:
Owning one or the other or both, eventually you will have to address the preamp tube replacement. Just thought I would add this which is more than most will be aware of before buying. If you do decide on one, just keep your hands out of the internals when handling the chassis. The caps can hold a charge for a long time after power was removed. There are internal bleed resistors to dissipate stored energy but if they fail, there is no way to tell by looking at the internals. Play it safe. It is not necessary to pull the chassis in most cases. Unless you had the JP2C limited edition. Not sure what to expect with the newly released Mark IIC+ Reissue. will be interesting to find out.
