I know the feeling. What year is your Mark V that you are willing to part with?
I have had the love/hate relationship with mine ever since I got it in 2012, the hate part of the relationship followed though shortly after having tube issues and since then it has just been the odd ball in my lineup. Why have I kept mine for so long? I often ask myself that question many times even now. If one wants that answer it would have to be the clean channel character that has held my interests this long. There is also one other thing that is easily overlooked and that stems from the CH3 character that is hard to replicate with all of my other amps including the JP-2C. Harmonics ! The Mark V is loaded with them. I have replaced the lead roll of my Mark V with the Roadster but that being said, it lacks harmonic content. Pinch off harmonics are next to impossible with the Roadster and they zing off with every attempt using the Mark V. I have noticed that the JP-2C that the harmonics are also a bit more difficult but yet still obtainable (depends on how you dial it in). It is obvious the Mark V has a fundamental tone that is different from most Mesa amps. However leads just jump with ease with the Mark V. One thing I did in a circuit mod was to remove a filtering capacitor that couples the grid to the cathode on one tube position (V4) that improved the response and feel of the Mark V. It is not an easy thing to do and if you decide to sell the amp, best leave it alone. That mod will make the CH3 brighter as well as improve the midrange content the amp has been lacking. If not for that trick I would have sold the Mark V as I found the 12AT7 tube swap does improve the distortion characteristic but does not address the fundamental tone issue. To me that was the last ditch effort that removed the Mark V from the "for sale" category. Note that this will not turn it into a MKIII or JP-2C. There is no way to get that JP-2C feel and bottom end power the Mark V is lacking for that sinister attack or palm muting perfection but I have learned to accept the Mark V for what it is and what it is not. So far the few amps I own that excel in palm muted tone would be the JP-2C or TC-50, the Mark V falls short but is much better than the Roadster or the RA100 for palm muted chords or chugging. Roadster drones out for palm muting on the modern voice of CH4 but that is the flavor that drives me to insanity for the heavy metal mayhem that may take place in my dwelling with that need is there (JP-2C takes that to another level and then some.) So far, I do not have an amp that overpowers the JP-2C in all its glory and thus I would agree with the desire to lessen the load. I may have gone to great lengths in order to attempt to bond with the Mark V and finally that is a reality but it took far more effort that what most would endure. From one extreme to the next I can finally say I like the Mark V. Started as a head and wound up converted to a combo, and it took a few speaker changes to become a favorite. Organic Timber Rhapsody was one savior among a few others that has changed my mind on this particular amp. However, that speaker seems best suited for the Mark V than say a Mark III or JP-2C. The V is okay with V30 speakers but tends to get ear heavy at times and becomes tiring too soon. I can play the JP-2C or TC-50 all day long though the V30 speaker and love every minute of it. Then there is the EVM12L black label speaker, that is one hard to beat cone driver that works equally well with the Roadster and the JP-2C as much as it does with the Mark V when applied in a 412 package. Considering how bright the Mark V can get, the OTR seems to compensate and does not reduce the midrange where as the EV seems to lack but has ample top end frequency. However when paired with the JP-2C in a 1x12 format the top end seems to be reduced a bit more than desired, and this roll off is not needed with the JP-2C, Roadster or TC-50. So when it comes to paper products and the driver used to push air it does make a difference on perception of the amp in question. Basically it boils down to your intended needs. the JP-2C or other Mark series amps may not offer the same versatility as the Mark V but it does much better at what the Mark V was targeted for, Heavy Metal and Hard Rock. Heck, even classic rock sounds better though the JP-2C than the Mark V in stock form. Actually I have yet a need to swap any tubes in the JP-2C as this amp is just nailed to awesomeness out of the box. So far the JP-2C has served me well though a single vertical 212 and recently got another so I can run a pair of them. WOW. I am still blown away by that experience and the OS Recto 412 cannot even come close to that. Do not be sad, be happy. It may be hard to let go of something that may not be ideal or suit your immediate needs. As someone else had mentioned you can always come back to the Mark V farm or wait and see what may happen next in the Mark line up.