Back in the 70's, I did extensive tube rolling with my 1971 Marshall JPM50. The only tube that seemed to respond was the phase inverter tube, but it really didn't result in a change that I would say was better or not. Back then, there weren't any Chinese or Russian tubes, so my experiments were with the established western brands like RCE, GE, Mullard, Sylvania. My conclusion at the time was that tube rolling was a pointless exercise. I currently have 3 Mesa amps, Mark IV Rev B, Mark V 90, and a JP-2C. I did some rolling on the Mark V when I first got it, and my conclusion is that tube rolling is even more of a pointless exercise with Mesas than it is with Marshalls.
Speakers are a whole different story. If you want to change the sound of your amp, speakers can give you a major shift in your sound. When I bought my used Mark V, it was a combo. I have owned combos in the past, and I hate the sound of open-back speakers. I bought a headshell and converted it to a head and sold the combo cabinet. It all depends on the genre of music you like of course, but I play hard rock and metal, and IMHO you cannot get a decent sound with those genres of music with open-back. Open back is fine for cleaner music, like Indie, jazz, country. I currently have a Marshall 4X12, a Mesa 4X12, Mesa 2X12, and a Mesa 1X12. All sound different, quite a bit different., from each other. The two that sound closest to each other are the 4X12 and 2X12 Mesas because they both have VIntage 30's in them.
Speakers are a whole different story. If you want to change the sound of your amp, speakers can give you a major shift in your sound. When I bought my used Mark V, it was a combo. I have owned combos in the past, and I hate the sound of open-back speakers. I bought a headshell and converted it to a head and sold the combo cabinet. It all depends on the genre of music you like of course, but I play hard rock and metal, and IMHO you cannot get a decent sound with those genres of music with open-back. Open back is fine for cleaner music, like Indie, jazz, country. I currently have a Marshall 4X12, a Mesa 4X12, Mesa 2X12, and a Mesa 1X12. All sound different, quite a bit different., from each other. The two that sound closest to each other are the 4X12 and 2X12 Mesas because they both have VIntage 30's in them.
