Am I losing my 6SN7in mind!?

Hoping to pick the brains of people more experienced with 6SN7 tubes than me.

I’ve been trying to go on a bit of a rolling spree to find my favorite 6SN7 tubes, and despite buying some tubes that are among the “best” (according to the “cools” on various forums), I’ve had some really curious results.

I’d love to know if I’m doing it wrong, or if anyone has had similar experiences. Here is what I’ve got right now:

From left to right (top row), we have (1) Sylvania “Bad Boys” (non-JAN) with matched date code, (2) more Sylvania “Bad Boys” (JAN) again with matched date code, (3) very non-exclusive Sylvanias I think from the 60’s, but I don’t actually know, and then (bottom) (4) Sylvania 6SN7W.

Pair (1) sounded very good (excellent clarity and presence), but one of the tubes, despite testing well, was very unstable (I could initially coax it to life with some tapping) and died on me about a week in. I didn’t really get to fully evaluate, but they sounded much better than… Pair (2) despite looking (and supposedly testing) NOS, sound absolutely dull dull dull (poor detail, veiled, poor treble extension) - least favorite pair here. Pair (3) came with my amp, and despite being the “no big deal” tubes have the most clarity, airiness, and detail of the bunch, and are my current favorite. Pair (4), which should theoretically be better than the black-base-yellow-label tubes are not as clean, a bit slower, and have slightly tubby bass.

Most pressing is that I can return pair (2), but am hesitating to do so because they look to be in fantastic condition, (supposedly) tested very well, and are theoretically among the best 6SN7 tubes out there. Could they really be that bad and open up after more burn in? I’ve got about 30 hours on them, and they’re no better so far. I’ve never had a tube get as much better as these would have to for me to be happy with the purchase. Also, one of the these was highly microphonic/static-y to start, but has mostly dropped that behavior (but not entirely).

Anyone else run into this kind of strange experience? Anything I should be trying?

Much thanks for any advice.

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My thoughts:

  1. Return pair 2.
  2. Get a full refund for pair 1 - fight tooth and nail with the place you bought it, the credit card company, PayPal, whatever you have to do. Those are used tubes sold as NOS.
  3. Understand it’s been well over a decade since “badboys” were identified as the holy grail 6SN7
  4. Consider the possibility that there are no more NOS (NEW old stock) badboys anywhere - they made a small amount for a very small period of time, and audiophiles gobbled them up long ago to stick in their Sagas and Cracks (with adapters).
  5. Stop buying tubes on eBay. Use Brent Jesse, upscale audio, etc. Find reputable places to shop.
  6. Input tubes that are microphonic and don’t resolve themselves in 50-ish hours (or less) of burn-in, will likely always be microphonic, and/or will probably get worse as they age. (Power tubes are a bit different). It also indicates they are probably used as well.
  7. The only way to truly know you’re getting a brand new tube is by purchasing new production units. The NOS world is a trap, especially for 6sn7. That’s why suggestion #5 is critical.

Honestly, NOS 6SN7 is one of the worst tube types to have to shop for right now. All the good ones are gone. Used ones might be okay, but they’re probably being sold as new, because they “test” as new. News flash: a tube will test as new for at least 75% of its life. This is why I stay away from amplifiers that use this tube type.

Oh, I almost forgot…

  1. Keep set 3. Does it really matter it’s not a bad boy? If that’s the one you like, use it.

Pair (4), which should theoretically be better than the black-base-yellow-label tubes are not as clean, a bit slower, and have slightly tubby bass.

Theoretically better how? Because they are military / ruggedized tubes? Something tells me the military didn’t care about high fidelity sound in the 40s and 50s. :wink:

If you want an actual good set of sounding tubes that won’t break the bank, look for Baldwin Organ tubes.


Number 5 is good info and Brent gives great advice.


Thanks @ProfFalkin ! To be fair, I knew pair 1 was used, and I’m okay with them not being NOS so long as I get some time out of them. Pair 2 was the one that bugged me the most. I’ve called Brent Jesse a bunch and also the folks at, and they’re my go-to folks. They just didn’t have the “bad boys” when I was looking for them.

Are either of you familiar with good new production variants for 6SN7s? NOS hunting is a massive pain in my butt. At least 300B and 274B have good new production tubes (Takatsuki, PSVane ACME, even “new” Western Electrics that are theoretically coming out some day…), but the only new 6SN7 variant I’m aware of are Sophia Electric and PSVane, and nobody seems to give them any love.


Also check out:

Longer wait and a tad bit pricier than Brent but he really finds the best of the best tubes and prices them accordingly all the way up to tubes for phono preamps down to tubes for a normal preamp


Paging @Paladin , who is one of the people buying up the world’s stockpile of NOS 6SN7s. Maybe he can give you some advice on what else to try, because I think he may have at least one of everything.

If you want to try a new production tube, @ValentineLuke liked the Sophia Blue, and he is one of the cools. I am definitely uncool, but I like the Treasure Globe. @pennstac is way cooler than me and he also liked the Treasure Globe.

And going back to vintage tubes, in this conversation, @stshields91 said he liked the Treasure Globe but thought the CBS-Hytron was even better.


Omg, this looks awesome. THANK YOU.


I came across those in my research, but they’re unfortunately too fat for the Woo WA5-LE (which may or may not even survive in my collection once the Pendant I just nabbed from @ProfFalkin arrives…)

I appreciate all the paging! See - I didn’t even know who the 6SN7 cools on this thread are :wink:


I bought the CBS-Hytron form Upscale as the link indicates. My impressions were based on use in a Lyr3. I bought a Euforia AE just after @andris posted his Euforia AE Woo WA5-LE shootout. As a result I’ve just ordered another Hytron to match the first one to try in the Euforia so I’ll be able to compare to the stock PSVanes in the Euforia AE to those. I can circle back here with impressions once it gets here.

I’ll admit I’m somewhat skeptical about the whole NOS tube thing. I do have a set of Bendix 6080’s and Tung Sol 5998 power tubes for the Euforia and they definitely do make a difference to my ears but the 6SN7’s it tried in the Lyr3 I really noticed minimal differences. The Hytron was the only NOS I tried. I’m eager to try a different set in the Euforia.


Oh, you’re the one who got his Pendant. Nice! I look forward to reading about your tube rolling conclusions for the Pendant once you’re finished with this. Right now, I like what Zach chose for mine.

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I received my first set of the new production WE 300B in October last year. That was from a pre-order I put in the day it went live (January 11, 2018). So, they have actually been shipping.

But this thread is about the 6SN7, which had become problematic enough to get the ones I really liked that I waited until my “next” amplifier was updated to use 13EM7 tubes instead of 6SN7 before I bought it.


Oh cool! Thoughts on the new WE300B’s, esp vs Takatsuki?

“Honestly, NOS 6SN7 is one of the worst tube types to have to shop for right now. All the good ones are gone. Used ones might be okay, but they’re probably being sold as new, because they “test” as new. News flash: a tube will test as new for at least 75% of its life. This is why I stay away from amplifiers that use this tube type.”

I’m completely in agreement and have had the sense that NOS tubes of many types are now actually UOS (Used Old Stock) for quite some time, and determining how much life is left before purchase can be almost impossible.

I have a decent number of driver and power tubes (8 and 9 pin) of various types in my inventory but have come around to accepting that many new 6SN7 tubes, as well as other types currently being manufactured (JJ and Electro-Harmonix, in the budget category) and Psvane, Shuguang, Treasure Globe, and Sophia Electric (in the not so budget category) will be my way forward in tube acquisition (should I even need to ever buy another tube at my age).

In new manufactured power tubes the new Gold Lion’s and Tung-Sol’s coming out of Russia have worked well for me.

And I’ve had good dealings with Brent Jesse, Upscale Audio, and a few others, over the years but as I said my tube buying days are probably over.

All things considered I’ve made piece with the obsession to collect tubes. I just want to listen to what I have at this point. I’ve even gotten away from the “tube of the week turnover” for listening. If I had all the money I spent on NOS over the past 5 years I could have a sufficient number of the current manufacture, expensive brands in my inventory (with generally some sort of warranty for the initial couple of months after purchase), to last me whatever number of years I have left.

I’d be okay with that.


First off, I do not agree that all the great 6sn7’s are gone, you just have to be patient in your shopping.

There are still plenty of great Russian tubes around made in the fifties and sixties, Foton and Melz. 50’s Fotons up to 1959 are very good and not expensive. The date code is to the lower right if the rhombus, many you will see on Ebay are from the sixties but keep looking. The Russian tube number is 6N8S.

Here is a great example of one of my favorite Melz tubes, generally called 1578’s. The 1963, year number is in the lower right of the logo.

The third photo shows what you should look for, metal upper supports, perforated plates, and a step sticking out on the bottom mica. Avoid other variations of this tube.

Both types of tubes suffered from solder issues in the tube pins so I remove and replace said solder before use.

If you get into much of this a tube tester helps a lot. I bought a large batch of 1963 Melz and sold most to friends, I was able to match pairs and quads because I had enough of them on hand. They did not last long. :grinning:

Black Glass Ken Rad VT-231’s are still around as well as grey glass RCA tubes, both tested extremely high in some of the blind listening tests I conducted.


Before I went with the Treasure Globe, I used an RCA “red base” 5692 for a while and that that was pretty decent. Some people don’t care for it, but it was better than several other tubes I found.

If you first go the the Grant Fidelity website, they lead you to:
Which lists not only the Treasure Globe, but PSVANE and a few other modern premium tubes. The PSVANE may fit in your amp.


I prefer CBS/Hytron 5692’s, but YMMV. Either is a 10,000 hour tube so they will serve you for many years.

Oddest tube I looked for lately was the Telefunken LS-50 used in German transmitters in WW 2. I was bet a considerable sum that I could not create a great sounding 15 watt SET amp using a bucket of parts handed me. I was given the Russian version of that tube to use, the GU- 50. Once I won the bet I started looking for better tubes.

I added separate volume pots and built a tiger maple and white walnut case. Another example of one of my amps is going out today as a loaner, lacewood and rainbow poplar.

I am running a winged C Svetlana tube from the 50’s for a power tube and an extremely rare Melz 1578 solid plate tube I believe was made when the factory ran out of perforated plates. I searched six months for more of those after I landed a 1956, the 1958 is equally as good.


If you have the technical knowledge, and tube testing equipment that is up to spec (and can repair if necessary), and the right soldering equipment and know-how / skill set, and are willing to accept money spent and lost for duds as part of the process, and have trusted supplier’s and are still maintaining that level of interest and desire and effort for more tubes … then go for it!

I would now like to focus on analyzing the music I listen to (sound qualities / characteristics and interpretation and performance) and do less analyzing of the sound of the hardware needed to listen to it with. It’s impossible to do one exclusively without the other, but I’m trying to change my emphasis.


There is quite a learning curve with tubes. Since I build amps for friends I am constantly looking for tubes to include with said amps. FLTWS is a friend and I often turn to him for his opinions on tubes, headphones and amps. I cannot begin to touch his knowledge of classical music and what it sounds like in different venues. I may like a particular tube or sound but that does not mean it is right for everyone.

Foton’s exhibit more bass
Melz (depending on the year) can give a wonderful balance over the entire spectrum


Ha - the last listing is from the same seller from whom I got my not-so-hot JAN “Bad Boys”. That said, I often give folks the benefit of the doubt at least once, and it’s entirely possible this pair tested well and just happened to be bad.

I’ve noted that even in the last year that stocks are drying up for various tubes. It’s almost as if you have to buy tube amps that run some of the good new production tubes rather than take a chance on NOS from questionable sources. Brent and the like only have so many to sell.

Or go to an amp that runs less traditional, but maybe still plentiful, NOS tubes.