Looking for thoughts/opinions on tube seller's response to my question...


Hi All!

I recently bought 4 balanced and matched reissue Tung Sol 6SN7GTB preamp tubes from a guy that I've bought 3 different sets of tubes from in the past (with no previous issue). 

I rolled out the early Russian tubes that came with my Schitt Freya and rolled in the new Tung Sols.  Immediately in system idle there is more noise in the form of hiss, scratchy air, etc.  I ran the Tong Sols for maybe 15 hours or so. No change. 

I emailed the seller to which he responded: 

The 6SN7GTB can take a break in period in some applications. If you Google you will see this phenomena is common. Run them in your equipment for 24 houts and re-evaluate. New ones I exchange would have the same break-in period. The factory has indicated it has to do with the cathode coatings used to extend tube life. No problem returning them if the problem persists.

Have you heard of cathode coatings causing this issue?  While I generally like NOS tubes a bit better than reissues, I've never had a new noisy reissue tube.  Also, I really do like purchasing tubes from better stocked places like Upscale Audio because this issue never seems a problem. But when it comes to new reissues, I don't look first to Upscale.  Maybe I should? 

I'm running them in to see what happens.  I'm not optimistic though. 


128x128jbhiller
Are these the same Tung Sols that Schiit sells for $100 ? Have you asked them about noise ? Did you remove and reinstall the tubes in different sockets ? I run high efficiency speakers and my system is susceptible to pre amp tube noise , especially when I rotate in the higher power amps . I will get more hiss , vibration feedback , and a ting sound when unmuting .  I Don’t have the Freya yet ( plan on one in about 2 months ). I also run isolation feet and Herbies dampeners . I’ve purchased from Upscale and consider them overpriced . I’ve also had a brand new Gold Lion KT-77 let go and damage an amp , so many things are possible. Good lunck, as I will be going there shortly . I will learn from you . Happy Listening , Mike. 
Good luck getting any help from Schiit. All my experiences
with their preamps sucked.
A few years ago I bought a quad of 80's Tesla EL34 tubes from Tubeworld and one of them was "dead" in the sense that it didn't start to glow and after a few seconds my amp shut down......switched to another socket; same thing. When I called Tubeworld the guy started telling me how to fix it but I cut him off immediately and told him that when I buy tubes I expect to have them in working condition right out of the box. I sent all four back and he replaced them; he also fixed the one not working tube, which I had stuck a piece of red tape on top to indicate the bad one. He sent me a pic of that tube glowing. Tubeworld is an ethical dealer. I also bought a pair of Telefunken ECC801S (12AT7) tubes from him a few years ago and they are wonderful. No worry about buying again from him. 
Others more knowledgeable about this, perhaps @mechans , could chime in here, but I recall something about 6SN7GTA vs 6SN7GTB compatibility being an issue on some circuits, but not others. Are you sure that the B is recommended on that piece of gear. If A is required, that could be the culprit. Cheers,
Spencer
Spencer, that tube was originally a 6SN7GT/G and the GT/A ant GT/B were later versions that were rated for higher plate watt and current. If you go to Brent Jessee Audiotubes you can find detailed descriptions of the different versions of these tubes as well as many others. He is also helpful if you send him an email if you have some technical question. Best tube dealer I’ve ever been involved with.