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
Have purchased perhaps 100 tubes for my two tube pre-amps and two tube power amps during the last 18 months.  Purpose is to inventory a stockpile good til I die since the price of NOS keeps climbing.  Of these, three (3) were noisy with crackling, creaking, or microphonics. I feel the only arguement acceptable for “breaking in” tubes is to allow them to mature to sound better.  It seems like the seller may be hedging that replacements from his shop could repeat the problem.  Flag.  If they are cracking/creeking out of the blocks I would consider that a defective tube or indicative an inferior manufacturing process.  In my case, sent them back for a refund and moved on.  Its good your seller offered up front to accept a return.  Good suggestions in previous responses where to find reliable tubes. 
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