I picked up a few of the Tung-Sol 12AX7A tubes. They are identical in appearance to the Electro Harmonix EH12AX7's. With the exception that the getter is slightly different. They have plenty of gain and are pretty linear sounding with a big bottom end. The highs are a little edgy and harsh like the other New Sensor (Sovtek offerings). They do not sound like the NOS Tung-Sol tubes. IMO they are beefed up versions of the Electro Harmonix 12AX7's with more gain and a more linear tone. I think these would do better in Hi Fi amps. They were very punchy and compressed sounding. I much prefer the JJ ECC803's for current production tubes. I would say these are the best Sovtek New Sensor 12AX7's. High gain users may like these more than rock or blues players.
to me, the 803's sound like regular JJ 12ax7's but not as dark and more 'complex'. the high end sounds very nice and 'airy'. i'm a fan for most amps. i prefer the standard JJ's in my soldano astroverb due to it being a very trebly and bright amp.
The ECC803 tubes are very sweet sounding with nice harmonics with average to high gain. They are not high gainers like the Chinese 12AX7's but have plenty on tap for most applications. I like the the ECC803's because they are very clear and detailed very transparent but also focused and forward sounding. The highs are very nice not dark like the JJ ECC83's. IMO I would say these are the best all around current production 12AX7 type tybes for almost any music type. There are others, but they seem to excell only in certain areas where this tube covers a wide spectrum.
I actually bought 3 of the Tung-Sol reissue tubes. And I was dissapointed in the tone. They are sitting in their respective boxes in my "tube drawer" Actually the plate materials have a big effect on tone. Every Sovtek, New Sensor preamp tube I have tried (I own versions of all of them) they all had that linear, harsh high end. Some people like them, which is just fine. But the re-issues are far from anything near a real Tung-Sol. I characterize the Tung-Sol 12AX7's as a upgraded version of the Electro Harmonix 12AX7EH.
Of all the tubes NS makes, (and I deal them so I have been throw a lot of them) the EH 12ax7 seem's to have the least harshness, and closer to vintage tube's like mullard/tungsol. (not that they sound anything like them, just less fizz on top)
They are bactch sensitive, and some EH-12ax7's are rounded, and pretty sweet yet fat sounding. you almost need to
buy a fe more then needed and weed out the fizzy ones. VDG