Problem is, no matter WHAT the amp or circuit, they just can't truly be cloned can they? Because no matter who tries (Plexi for one) these clones still don't sound or feel like the originals. The circuit is EXACTLY the same, right value resistors/caps throughout, yet they are still far apart soundwise? Because the TYPES of resistors and caps aren't made anymore nor are the transformers. So they won't be the same, no matter what anyone says about 'it's not voodoo' they still cannot clone correctly any of these amps because the vintage parts used are LONG GONE.
That's why the originals will always be sought out, because no clone will sound like them.
This is a good thread.
Although I have no interest in circuit cloning, so wasn't commenting on that, your statement on parts selection requires some nuance. This is a matter of diminishing returns. No amp sounds quite like itself from day to day due to thermal, voltage and even humidity variations, and no two of the 'same' amps off the assembly line, especially those with a great deal of hand labor to build like an early Mesa Mark or Marshall Plexi will sound exactly alike. Therefore, if you WANT to talk about cloning, it's a bit like tilting at windmills. Are you also using those terrible Black Diamond strings, a real PAF...do you have a brand new old stock greenback which hasn't been worn out...NOS tubes...dare I say technique...the list goes on and on.
The good news is that from a parts selection perspective, you don't need all vintage components to sound good. Certain locations of the circuit have a greater influence on tone, and for those if you have to replace a failed small signal component it is worth tracking down a quality vintage part. I think Metroamp has demonstrated with some smart analysis you can pretty well recreate a specific example of a vintage amp by using the critical quality components where they matter most.
Where the story gets harder is with the high voltage (crappy) electrolytic capacitors. Even if you could find NOS versions on ebay, it would be silly to use them because they are probably questionable. Which brings me to the amps. I agree the original Marks will always be sought out, but they are now at the troublesome age of needing new electrolytics. You can delay this service because you like the tone, but soon those are going to be toast, and when they leak they will likely damage those beautiful hand-drawn circuit boards, and if they fail catastrophically they could damage adjacent components as well. When this happens in the future, if Mesa is no longer able to service the vintage amps, hopefully there will be an accurate schematic to put humpty dumpty back together again and solder in some jumpers to repair the boards (this is where the Marshall turret board construction method makes things easier). It won't sound exactly the same because the parasitics have changed in the layout. It will also get brand new caps, so likewise won't sound the same. None of the amps will over time, and that's the cycle of electronics. They will turn into at least a partial ship of theseus. (isn't folklore that Adam Jones keeps his SuperBass in a freezer to delay this, lol, much vanity)
I bring this up because these products are cool, and I want your crap to work. All of the awesome vintage digital effects processors from the 80's are going through this phase right now as well, they all need new electrolytics or they turn into Eventide doorstops (or degrade into really noisy/unusable machines, plus the EEPROMS will likely start failing in another decade or two). In general the digital stuff is more fickle to component degradation than analog amps, and you can certainly find examples of old Superleads rocking their original caps, but the clock is ticking and they definitely don't sound like when they were new, even if they sound good.
Just something to think about. Option 1: get it serviced/recapped now by Mike before he leaves, buy yourself another 30-40 years piece of mind, but possibly lose some sweet toans (isn't it all metal anyways, haha). On the other hand do nothing, enjoy your vintage Mesa until it does fail, and hope the factory is still willing to service the vintage stuff and/or local techs finally have access to the right schematics to help you out. Hope they don't unintentionally disable some of the custom circuit tweaks due to lack of documentation.
Analogy time: I remember when Harley Davidson stopped carrying parts for or servicing anything with a carburetor, because they didn't want to train their techs on the old stuff and wanted their customers to purchase new bikes instead of wrenching. Fortunately the body of knowledge had migrated to the public, so you can find all kinds of mom&pop parts suppliers and techs. This has already happened with the old Marshall designs, and similarly will need to happen with Mesa to keep the old Marks happy for years to come.
The Triaxis is a whole other level of timebomb though, haha. I need to buy 4 for future organ transplants.
WIMPS beast of an amp.
