you are welcome, no need to apologize, the information will be here.
I am also disappointed with the STR445 tubes. They were ok in the MWDR which is what they are currently building as Rectifiers are concerned. Ok meaning they will work but there is so much content missing from the amp that I was getting with the STR440 tubes. The MWDR came with the STR440 gray bias color which was the same used in the JP2C. I bought the JP in 2016 and the MWDR in 2018.
I would not say it was like placing a blanket over the amp, it was more of a neuter job with ill effects because it lost its balls. If I never heard the MWDR with the STR440 tubes I would think the MWDR was just ok but not great. The STR440 just opens the amp up and rips like it should. Without any changes to the preamp section (all stock Mesa tubes) I thought the STR448 were ok as well, they had more of a blanket effect on the amp. However, I was able to run a 7 string through that amp without the mud, I got this really unique low end grind I never experienced before. 6 string with standard tuning just sounded weak in structure, more on the thin side. STR440 tube is way better. I never respected them before, but now I do.
Roadster, I admit I replaced the preamp tubes with old Mesa Chinese 12ax7 made in 1990. I wanted to see what effect they would have on the amp. I lost the low end drone and gained more aggressiveness. The STR448, I do not remember how they sounded. The STR445 was just swamped with low end and made it sound like no mids or treble, just bass. That was odd. I really like the STR440 reds in the amp, never tried those before. It was always the yellows. I tried green, and gray and though it was just too much more fizz, less detail. So with the yellows or the Reds along with the complement of old Mesa preamp tubes, I was able to play the amp with the 7-string without any mud or low end drone swamping the tone. Had I realized that would actually work I would have been using them long ago. I found the Mesa (JJ ECC83s) to be less than ideal in the Roadster. Very much like I found with the Mark V90, they suck. However, the MWDR, JP2C, Badlander, TC100, TC50, and the Mark VII they seem to be good for those amps as if the circuits were specifically tuned for the preamp tubes. I have tried other preamp tubes in the amps mentioned only to find the stock Mesa branded JJ ECC83s to sound the best.
I still have both Roadster and MWDR out in my way of my stereo rig I have set up with 2 BADS, and the Mark VII or may even bring out the RA100 again. Sort of miss using that amp. I may revisit the power tubes with the Roadster and MWDR as I was more or less under the weather with COVID when I did it. Perhaps my hearing is better now that I am free from the illness. I will give it another try this weekend.