Shootout of Nos 6sn7 tubes

[DaveC]

I still use the Soviet Melz metal-base tubes (black plates, no holes), for my preamp output and amp driver tubes, along with their 6SL7 variant for voltage gain.

The nice thing about 6SN7 is their overall superior design means they are one of the most linear tubes, and while there are differences, they are all good tubes. At least I haven't found any bad ones yet, although I admit I haven't specifically tried.

Some may be overhyped, for example I agree with the author of the article Marty just posted that 5692 tend to sound a bit flat. Low-noise for sure, but subdued in their overall presentation.

 

[Lowrider75]

I see that they’re sold- did you buy them?

I’ve made a couple of purchases from that seller in the past and he typically offers nice stuff but the prices he’s been putting 6SN7’s at within the last six months or so are outrageous.

No, I didn't buy them. That price is way too high. In fact, I'm surprised they sold.

 

[Mendel]

Here's a nice review of 6SN7s from a few years ago from a respected tubophile.

The Basement Stereo Tube Stash

Partial look at the tube stash that keeps my 45 driven basement system going. The 6SN7 is my driver of choice and h...

robertmusic.blogspot.com

I admit I just don't understand the fascination with the overhyped TungSol BGRPs. At any price. They were popular with owners of Lampizator DACs a while ago on this forum but I think most people have moved on from them.

Never seen that review before. Agree with most of it, particularly the comments on the red based 5692 (very flat as a driver tube, maybe better for input or preamp duty) and the Canadian brown base GE tubes (very good tubes!). I wouldn’t call the early National Union black glass 6SN7s neutral but they are definitely musical.
Keep in mind that his description and preference for these tubes (and mine as well) is based on them being used as drivers in an amp. If the usage was different, the preferences would likely be different as well.

 

[Re-tread]

UPDATE: Picking up on my proposed "6SN7" path (last described in entry #248 above), I have a small update of my proposed "trajectory" of my 6SN7 trek.

Refresher: My baseline is still currently the 1955 RCA "Grey Bottle" 6SN7 in my PreAmp; and, I was going to try a NOS 1940's Sylvania VT-231 6SN7GT soon.

Quasi-Update: Well, the acquisition of my Sylvania VT-231 fell through. I think the vendor may have been a spoof, but I am not sure. Luckily, I was swiftly (and fully) refunded.

New Path Forward: So, with the above deal gone amok, I purchased the following 3 tubes (which all now have actual parcel tracking numbers).

1. A 1950's/1960's Tungsram 6SN7. This tube is never discussed much, so it must be a sleeper. I learned of this tube when I owned a New Audio Frontiers Absolute Mk3 preamp. I believe Tungsram is from Hungary, but I don't know (for sure) if Tungsram actually produced them, or, had them private labeled from GE, whom Tungsram was (much later) co-mingled with. This is the tube NAF selected for their preamps, so I am hoping it shows well (i.e., sounds good) versus the others. Fingers crossed.



2. A used(?) 1940's Sylvania VT-231 6SN7GT. This is the tube I am very interested in trying, and luckily, I found another one to buy. The price for this one was less (than from the NOS deal that previously fell through), but, it may not be as pristine of a specimen... meaning it may be slightly used (not sure), so this one may not be categorically NOS anymore. But, it should be a legitimate tube, based on the photo anyhow:



3. A 1950's JAN Sylvania 6SN7WGTA "Chrome Dome". I really have no ideas about this one either, but I will have a go with it:



So, in concluding this entry, I will soon have a chance to try these 3 varieties in about a week. Hopefully I will find a wonderful tube that "pairs really well" with my system. Thanks to everyone (thus far) for your reports, suggestions, and insights.

Re-tread

 

[Mendel]

UPDATE: Picking up on my proposed "6SN7" path (last described in entry #248 above), I have a small update of my proposed "trajectory" of my 6SN7 trek.

Refresher: My baseline is still currently the 1955 RCA "Grey Bottle" 6SN7 in my PreAmp; and, I was going to try a NOS 1940's Sylvania VT-231 6SN7GT soon.

Quasi-Update: Well, the purchase of my Sylvania VT-231 on eBay fell through. I think the vendor may have been a spoof, but I am not sure. Luckily, I was swiftly (and fully) refunded by eBay.

New Path Forward: So, with the above deal gone amok, I purchased the following 3 tubes (which all now have actual parcel tracking numbers).

1. A 1950's/1960's Tungsram 6SN7. This tube is never discussed much, so it must be a sleeper. I learned of this tube when I owned a New Audio Frontiers Absolute Mk3 preamp. I believe Tungsram is from Hungary, but I don't know (for sure) if Tungsram actually produced them, or, had them private labeled from GE, whom Tungsram was (much later) co-mingled with. This is the tube NAF selected for their preamps, so I am hoping it shows well (i.e., sounds good) versus the others. Fingers crossed.

View attachment 136792

2. A used(?) 1940's Sylvania VT-231 6SN7GT. This is the tube I am very interested in trying, and luckily, I found another one to buy. The price for this one was less (than from the NOS deal that previously fell through), but, it may not be as pristine of a specimen... meaning it may be slightly used (not sure), so this one may not be categorically NOS anymore. But, it should be a legitimate tube, based on the photo anyhow:

View attachment 136795

3. A 1950's JAN Sylvania 6SN7WGTA "Chrome Dome". I have really have not ideas about this one either, but I will have a go with it:

View attachment 136796

So, in concluding this entry, I will soon have a chance to try these 3 varieties in about a week. Hopefully I will find a wonderful tube that "pairs really well" with my system. Thanks to everyone (thus far) for your reports, suggestions, and insights.

Re-tread

That Tungsram looks interesting. I don’t believe Tungsram made a 6SN7 but apparently some of the British Brimars and GEC 6SN7s were labeled “Tungsram”. If it is one of those you may have a real winner, possibly the seller had no idea what he was selling. Can’t really tell from your photo, it could even be Russian if it has the “flying saucer” getter. It definitely does not look like a GE. Not much info on those tubes and I have personally never seen one. Hard to say what you got.
Don’t sweat it over NOS. In my opinion true “NOS” tubes from the 1950s and 1960s are as common as Unicorns (well maybe a little more common but not much). If they test new, they sound new most of the time.
Let us know how the tube rolling goes when you get them.

 

[Re-tread]

If interested/helpful to the discourse, here are 2 more photos of the (my) forthcoming Tungsram 6SN7GT tube:




The print, font, and glass here all look like the previous Tungsram 6SN7GT tubes that were in my previous New Audio Frontier Absolute Mark 3 preamp.

Re-tread

 

[Lowrider75]

If interested/helpful to the discourse, here are 2 more photos of the (my) forthcoming Tungsram 6SN7GT tube:

View attachment 136811
View attachment 136812

Re-tread

"Tungsram Garantito"...that's Italian. The box looks new, tubes look vintage.

 

[Re-tread]

"Tungsram Garantito"...that's Italian. The box looks new, tubes look vintage.

+1. I agree on both points. Fingers crossed.

Re-tread

 

[Designsfx]

If interested/helpful to the discourse, here are 2 more photos of the (my) forthcoming Tungsram 6SN7GT tube:

The print, font, and glass here all look like the previous Tungsram 6SN7GT tubes that were in my previous New Audio Frontier Absolute Mark 3 preamp.

Re-tread

I would suggest doing a quick search through the “6SN7 Tube Addicts” thread over at Head Fi. There’s a lot of info to be found there.

 

[Lowrider75]

If interested/helpful to the discourse, here are 2 more photos of the (my) forthcoming Tungsram 6SN7GT tube:

View attachment 136811
View attachment 136812

The print, font, and glass here all look like the previous Tungsram 6SN7GT tubes that were in my previous New Audio Frontier Absolute Mark 3 preamp.

Re-tread

Here's some info, scroll down:

6SN7 Tube Addicts

Dear Blackmore, Thanks for the info. I would not do crazy purchase. I have not been told about the price yet. I will ask him about the plate. What is the difference between the Harleem made, Eindhoven ....... Philips Pope, Philips Miniwatt, Chelmer . I also read once in...

www.head-fi.org

The Tungsram Hungary factory closed in 1956, that's when the Mullard factory began manufacturing Tungsram. All of these Tungsram are stamped Made in England.
This doesn't help identify your tubes, but it's doubtful they were made in England.
IMO, they're either older tubes from Hungary or made somewhere else and rebranded.

 

[Re-tread]

Thank you very much for providing this historical context. The production history (of this tube, and many tubes) is very interesting, however, (for a newbie) getting a specific tube "identified" to production dates, location, and an OEM manufacture can be challenging.

Re-tread

 

[Re-tread]

Good news! I received my 1950's Tungsram 6SN7GT tube today, and promptly installed it in my PreAmp, and music is flowing.

Baseline refresher: replacing my 1950's RCA "grey glass" 6SN7GT (cited above in entry # 245) with this NOS 1950's Tungsram 6SN7GT (new photos below) in the input section of my custom Blue Circle NSC preamp.

Initial sonic impressions: With only 3-hours of play time, I can report (at this point) I am real happy with the direction this tube has taken the sound of my system. Moving from the previous RCA, this Tungsram has introduced more details, space, treble presence - all of this upside with no sonic detractors (IMHO). I am guarded to increase the treble at the cost of losing density, body or low-end energy, but (so far) this tube has introduced no such detractors.

I have also noted (while listening to Bill Evans live at the Trident, 1964) that the lower energy (the mids, lower-mids, and the bass) seem to be less congested, offering more space for the bottom-end energy to emit/emerge. A real nice improvement (too!). Can I say "clearer" ? Sure, why not.


Images for the record: Because the Tungsram 6SN7GT seems a bit of a sleeper, and flies under the radar of most discussions, I will post a few candid photos from today's unboxing so these visuals may help archive some of the tube's legacy:

Font:



Plates:



Getter:



QUESTION: Approximately how many hours of "play time" does a new 6SN7 tube (in the input stage of a preamp) take to completely break-in? Does (will) it go through any break-in pains??

Next: It will be interesting to see how the forthcoming 1940's Slyvania VT-231 6SN7 tube compares, when it arrives in several weeks. These few weeks will give me some time to get familiar with the Tungsram, prior to the Sylvania VT-231.

Re-tread

 

[Lowrider75]

QUESTION: Approximately how many hours of "play time" does a new 6SN7 tube (in the input stage of a preamp) take to completely break-in? Does (will) it go through any break-in pains??

Next: It will be interesting to see how the forthcoming 1940's Slyvania VT-231 6SN7 tube compares, when it arrives in several weeks. These few weeks will give me some time to get familiar with the Tungsram, prior to the Sylvania VT-231.

That's great news. If a tube is true NOS from 1940s, 50s, 60s, burn-in can take 50 to 60 hours. Most tubes these days are not true NOS, they have been used for a few hours and put back in the box. They will test in the "New" range and appear clean so sellers cheat and call them NOS or NIB (new in box).

I just bought a pair of 1961 RCA GTBs that the seller called NOS/NIB. The fact that they were fully burned in at 15 hours tells me that they were slightly used.

 

[Lowrider75]

That's great news. If a tube is true NOS from 1940s, 50s, 60s, burn-in can take 50 to 60 hours. Most tubes these days are not true NOS, they have been used for a few hours and put back in the box. They will test in the "New" range and appear clean so sellers cheat and call them NOS or NIB (new in box).

I just bought a pair of 1961 RCA GTBs that the seller called NOS/NIB. The fact that they were fully burned in at 15 hours tells me that they were slightly used.

And preamp and amp input tubes will burn-in with the power on. Music does not need to be playing.

BTW, I'm using Tungsram Hungary NOS 12AU7s in my preamp and they sound wonderful.
Clarity is the word I would use to describe a Tungsram's presentation. They are spacious and extended with smooth highs.

 

[Mendel]

Re-tread.
Can you take a picture of the bottom getter? Is it square, halo or “flying saucer”? That will help identify the tube.

 

[Re-tread]

Greetings @Mendel ,

Re-tread.
Can you take a picture of the bottom getter? Is it square, halo or “flying saucer”? That will help identify the tube.

Unfortunately, I don't recall the shape. I did go through the photos I have taken of the tube to date, and none show the "bottom getter" clearly. And, unfortunately, I put the cover back on yesterday afternoon, so there will be a small delay getting this photo.

When the forthcoming 1940's Sylvania VT-231 6SN7 tube arrives (in about 3-weeks?), I will remove the preamp cover again to try the Sylvania versus the Tungsram. When I do get a of photo of the Tungsram, I will either post it in this thread or send it to you PM. Then, you can ID the shape (as I don't really know what halo and flying saucer look like).

Re-tread

 

[Re-tread]

Greetings @Lowrider75

If a tube is true NOS from 1940s, 50s, 60s, burn-in can take 50 to 60 hours.

And preamp and amp input tubes will burn-in with the power on. Music does not need to be playing.

Thank you for these data points. Good to know.

BTW, I'm using Tungsram Hungary NOS 12AU7s in my preamp and they sound wonderful.
Clarity is the word I would use to describe a Tungsram's presentation. They are spacious and extended with smooth highs.

Nice...!!


Follow-up question (and @thomask can to chime-in on this, too): can you describe how you would expect the sound a NOS 6SN7 tube to fluctuate over the first 60-hours? Will they mellow or remain crisp? I am hoping mostly the latter...

Re-tread

 

[Re-tread]

Re-tread.
Can you take a picture of the bottom getter? Is it square, halo or “flying saucer”? That will help identify the tube.

@Mendel

I went into the preamp yesterday (in preparation for trying the next tube, the forthcoming 1940's Sylvania VT-231 6SN7GT), and was able to snap this picture of the "bottom getter" of the 1950's? Tungsram 6SN7 for (you and) the thread.

Bottom Getter:



I hope that gives you some clarity on how it appears.

Next: I should be able to report soon (e.g., in the next few days) on how my just received 1940's Sylvania VT-231 6SN7 GT is sounding in my system.

Re-tread

 

[Mendel]

@Mendel

I went into the preamp yesterday (in preparation for trying the next tube, the forthcoming 1940's Sylvania VT-231 6SN7GT), and was able to snap this picture of the "bottom getter" of the 1950's? Tungsram 6SN7 for (you and) the thread.

Bottom Getter:

View attachment 137331

I hope that gives you some clarity on how it appears.

Next: I should be able to report soon (e.g., in the next few days) on how my just received 1940's Sylvania VT-231 6SN7 GT is sounding in my system.

Re-tread

Actually the above picture does not show the getter. But after looking through this thread again in noticed that your post #272 shows the getter in the middle picture marked “plates” at the bottom of the tube. Clearly a solid disc “flying saucer” getter. Definitely Russian made. That doesn’t mean it doesn’t sound good, as you have noted. Russia made some fine 6SN7 types. Enjoy the Roll!

 

[we421a]

I have been using the Tungsol round plate black glass 6sn7gt vt-231 for the last 20 years and I have not found any tube better for my preamp and amps that use 6sn7 tubes in line and driver/input stage. The second on my list is the Mullard cv-181. These are slightly brighter than my reference tungsol. I can see that some might think it's more resolving but it is not necessarily better in my system. I finally tried out the 6J5 tubes this year with some adapter and on new tube amps. The top of the list 6J5 is good but not the same as the 6SN7 tungsol. The Mullard 6J5 sounds very similar to the ECC32 cv181. The Osram L63 with smoke glass is like dark thick chocolate. It is nice to smooth out the bright system. The American brands from Tungsol, Sylvania, Philco, and RCA 6J5 ST or glass straight bottles are also nice. They are less bright than the Mullard and relatively cheap. With the best combination of the 6J5s, they can sound nice and work as the 6SN7 substitutes in my setup. However, the best 6J5 tube combos do not have the same sound as the 6SN7 tungsol round plate black glass. The majority of 6J5 does sound better than most of the 6SN7 in my setup. They are a bargain. My next choice would be the Sylvania 6SN7W metal base. They are not as clear as the Tungsol but they do sound nice. For the budget 6sn7, I find the Sylvania 6sn7wgt yellow letter chrome top ones acceptable.