Anyone ever have, use or hear this tube?

Yes , I bought 4 of them about 7-8 years ago for $500. The seller had 5 pair, I bought 2. At that price I regret not buying all of them. I have multiple sets of Tektronix labeled Tekefunkens to compare them with , and they are dead quiet. In my Mid Fi system I can’t tell any difference in tone or soundstage Vs the Tektronix. I also have various Seimens and Amperex and they don’t come close to the Telefunkens in terms of a flat response or depth of sound. It’s sad that NOS tubes are very limited and have become unaffordable. I got back into tubes about 10 years ago after a 30 year absence and went on a tube rolling binge. For me it was such a satisfying experience experimenting with tube rolling and different types of music. 

   @mesch, please let me know if you like them. I’ve tried about a dozen different 12AU7’s and just prefer Telefunkens. That being said Tungsram 12 AU7’s and the nos Tesla ecc82’s  ( Not JJ’s ), sound similar to Telefunkens and are considerably less. As far as nos Mullards, you either love em or dislike em, I’m the latter as they throw a veil over the music. I run a paltry Rogue RP-1 with upgraded footers, power cable and nice interconnects. It actually sounds good for having reached its limit. I’ve not played with the Sphinx , but if it’s not too bright the tubes I mentioned would probably be good. Considering it ships with JJ’s pretty much anything will be an improvement. Happy Hunting, Mike B.