Old Boogie MKIII - finally! - and tube question

[Anje]

I recently got my first 80's MKIII Mesa Boogie; after a few decades of playing the guitar, never too late
UK classic / vintage amps have always been my main kind of amps and for some reason those Boogie had eluded me, I felt it was time to address this gap.
In the spirit of doing it for good I got a pair ; I always like to compare several examples and be able to run a stereo / dual mono / wet-dry rig:
"+" no stripe combo (with EV12L)
Purple stripe long head (export PT)
both 100w Simul-class with the GEQ; recent maintenance/tech checked but no "mods" I'm aware of.

Could you please share what you preferred tubes for those amps (power esp) are?
I did a search here but couldn't really find a thread focused on this question.
The head has recent JJ 6L6+EL34
The combo has Sovtek 5881 (WXT); I was quite surprised about this.

Here there are, my little "US corner" looks almost complete now :

 

[ChurchHill]

Nice! Wish I could help with a tube recommendation. I've never really rolled tubes through mine, just use whatever Mesa is selling usually. Mark IIIs don't seem to be nearly as sensitive to power tubes as Marshalls or Fenders are. Preamp tubes are a different story, though. Again, I usually just stick with Mesa SPAX7-A, although I've had good luck with Chinese 12AX7s and various NOS US tubes, RCA, Sylvania, etc.

Hope you enjoy your new Boogies and much as I enjoy mine!

 

[Dfwxjer1]

Smart move, buying the pair

Congrats, I have loved all the Mark series amps I've owned along the way, but the Mark III always stood out as my favorite.

 

[mentoneman]

welcome and nice score!
i normally run all boogie tubes.

 

[Chase42147]

Congrats on picking up a Mark III, definitely one of the greatest amps ever built

 

[Anje]

Thanks guys!

About the power tubes:
I have in mind Mesa Boogie has been offering several different “STR” models, which I guess correspond to different rebranded tube manufacturers/models.
For those of you using & liking Mesa tubes, do you know the STR model?

 

[mentoneman]

from the boogie forum:

“STR as we know stands for Special Tube Request. This can be as simple as the color of the plastic base, size of the pins, content of gold on the control grid, shape of the control grid, materials used for the plates and so on. It can be as simple as no logo on the glass. Without seeing the actual work order for the specific tube, it is all based on speculation. Just for reference, the old STR440 tubes made for Mesa sound nothing like the tubes offered by Ruby Tubes as the equivalent or same tube. It may just boil down to how the tube sorting process may differ.

Mesa color codes are miss leading. Have you ever had a chance to run different colors of the same tube? I have every color except for blue or white in the STR440. Reds have the highest headroom. Yellows are moderate headroom, Green is middle of the road so it has a higher degree of early distortion characteristics. Greys will have less headroom and more early distortion characteristics. Just hearing the difference with a given amp and trying out sets of specific colors. Also a good indication how much a given amp relies on power tube distortion. That is how I interpret what the color grading system is. Not what they say it is but how it sounds. And yes, you can hear the difference between the color match codes. (depends on the amp though, if Simul Class, probably not as noticeable, but a Class AB amp, you will notice). The JP2C was one amp I took notice of this characteristic. As for the Mark V90, it was not as transparent. An amp like the Roadster, it was more noted on how muddy the amp got with tubes having more distortion characteristics (I believe the term or phrase many tube supplies use is "onset of early distortion"). At the time I was shopping for power tubes from Doug's Tubes, he asked me what distortion characteristic do I want in reference to the 1990's Groove Tubes GT6L6GCR-2 gold series, aka Svetlana 6L6GC manufactured in St. Petersburg, Russia ( SED =C= 6L6GC and not the fake Svetlana made by Reflektor in Saratov, Russia which are just 7851A with a different logo and base.) After that, it began to make sense. The JP2C was more dependent on the early distortion characteristic than realized as the Red coded tubes sounded totally lame, grey coded tubes were more desired for the STR440. However, the STR415 has its own unique tone and characteristic that is not replicated by a tube with the same color code. If that were the case, an STR441 in green would have the same sound qualities. Fat chance. Those tubes were lame in the JP2C even with more early distortion. They do work well in the Mark V90 Simul-Class. “

 

[nightlight]

Nice score. The Mark III is a sweet amp, and having two of them is a good idea.

 

[Anje]

I found this page on Mesa site, listing the main different STR tube models, I see that the Sovtek 5881 are the STR 425:

https://legacy.mesaboogie.com/tubes/power-tubes/index.html

 

[Anje]

Another tube question for MKIII experienced owners:
do you prefer / recommend the mixed 6L6/EL34 setup in a Simul-class amp, or full 6L6? What do you feel the difference is in the same amp?