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. 


jbhiller
Never heard of this problem. One time with reissues there was some hiss but they became quiet with some run-in. 
At least you can return them if need be. I've purchased reissues from Upscale and have no problems.

If you want quiet tubes(essential, for a preamp or phono stage), Upscale sells a, "Platinum Grade", available in most of their lines. I’ve never had a noisy tube, that quieted down after burn in. However, I’ve never bought anything but NOS, 1940s, 6SN7s so, what do I know? (https://www.upscaleaudio.com/collections/vacuum-tubes/products/tung-sol-6sn7gtb?variant=21830453701) Kevin’s grading is mentioned, toward the middle of the page.
Yes, I like upscale and don’t have this problem with their product. This is new to me with reissues. I’m running them in to 100 hours. I doubt it will help but let’s see. 
Check out vintage tube services; the guy rates his tubes in four categories from line to moving coil. And stay away from current production Russian and Chinese stuff; you will be better off buying NOS as they sound much better and last much longer. I never could understand why someone will pay hundreds or thousands of bucks for equipment and then use the junk tubes it came with or think they're upgrading by buying more of the same.
I agree with  bsmg.   ie: You might consider contacting the following, regarding the, " 6SN7GT Sylvania, triangular blackplate clearglass, bottom-getter, medium glass envelope, "Bad Boy"type.MATCHED PAIR" tubes that he has listed on this page:  http://www.audiotubes.com/6sn7.htm  They won't break the bank and have a wonderful, clean sound.  The bottom-gettered, 1940's, Ken-Rad VT-231 is another very nice tube.    I'm certain, Brent could find you a very quiet pair of either.  Their sound is close to the Tung-Sol, Round Plate, JAN CTL and/or Sylvania 6SN7W(metal base), that some of us are paying so damned much for.   
Never heard of the special coating. 
Upscale I’m sorry is a rip-off.
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
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.
Andy at Vintage Tube services as mentioned above. A wizard with awesome test equipment and ethics.

Roger M at RAM has probably the most modern testing and grading equipment on the planet....

 I can only recommend Antique Tube Supply for quality tested tubes. Andy has been around for a long time, and nobody out there does the testing the way that he does.
Another vote for Andy at Vintage Tube Services ( I imagine that’s what 4know meant to type?). He has a great selection of quality NOS tubes, a plethora of experience and knowledge and is great to work with. 
Andy's Vintage Tubes is the only tube seller I have 100% confidence in.  You may get lucky elsewhere for a little less money but why risk it?