Hello Jdurso,
is that Roadster a combo or a head? I find it interesting that the only instances where I've seen tubes with damage to the bottom like this have been from Mesa users on this forum! Could it be that those military quality ceramic preamp tube sockets have a bit too ferocious of a grip to the pins and therefore are preamp tubes a bit sensitive as to how they are inserted and pulled? I have no experience with Sovtek LPS. I do have experience with nearly any vintage old stock (VOS)12ax7 ever made.
The siemens you picture is a long ribbed plate 12ax7, not as common as their shortplate 12ax7. Four types of Siemens 12ax7's exist: the shortplate ecc83, which is most common and the design resembles the short plate Mullard and Amperex bugle boy, the e83cc, a shortplate that has an extra mica and more robust getter halo support, the king daddy of them all, rated 10,000 hours, the long smoothplate ecc83 resembling the famed Telefunken smoothplate but with no diamond between the pins, sometimes found in the e83cc designation, and the long ribbed plate which is your tube. It has less of a midrange than the shortplate siemens types, but has a bit more upper mid and top end complexity to its tone. That's the good news, the dirty tone is rich in harmonics, the bad news is that they are prone to being microphonic,k which is not a good thing to have in a combo amp with the kind of massive power a roadster has.
If you do have a combo, I'd like to suggest you purchase an RFT 12ax7 if that siemens was sitting in a dirty channel spot. The distortion is very smooth, lots of mids and decent top end, it's design is among the most resistant to microphonics of any 12ax7 ever made. They are found on eBay for 30 45 bucks each plus shipping and are worth every penny, often rebranded with other labeling. Two other 12ax7's which offer a similar bright top end are the Matsushita short plate12ax7 with 45 degree getter halo, the infamous "Japanese Mullard" made on Mulllard tooling in Japan, and the hard to find raytheon long grayplate 12ax7a organ tube sometimes found with the yellow Baldwin labe. The long blackplate raytheon 12ax7a organ tube is slightly less bright than the hard to find grayplate, and it is wonderful sounding with a bit less top end. All of these tubes suggested are more resistant to microphonics than that siemens of yours. The Rays have a partial 3rd mica on top of the top mica to damp vibrations, the Matsushitas are so well made that I never has seen a microphonic one, and I have several of them, they need to be used like a few hundred to maybe a thousand hours to get them broken in, (Really!) their top end is particularly bright. All of these tubes offer wonderful sounding distortion dripping in harmonics, with plenty of mids and a decent but not overwhelming bottom. The uber-spendy siemens e83cc short grayplate is one of my two or three fave 12ax7 types of all time, but they cost like 80-120 bucks apiece NOS or slightly used VOS, but worth it if the one you get is not a bit microphonic. Huge mids like their Mullard shortplate cousins but more complex when smacked into the dirty. All can be found on ebay. The matsushitas commonly go for like 20 bucks or less each, the rays 20-30 ballpark. Again, I recommend the RFT if you have a combo amp, it won't sound like the Siemens you had, but I'd be very surprised if you didn't like it one heck of a lot anyway. You might get a Jones to start collecting vintage tubes, Shredd got you a very good one. YOu have a taste for very nice equipment, great tubes make great equipment sound greater.
Hope this helps you, I have greatly enjoyed reading your posts here. Peace.
