Shootout of Nos 6sn7 tubes

@dlcockrum thought I would give an update on the Linlai E-6sn7 after 120+ hours.  The strong bass has declined to be very average, the highs are bright and don’t sound real, and the midrange has declined and sounds muffled.  It does sound better at higher volumes but still to solid state like for me.  I would not recommend it now and have started a return.  Maybe on other systems it sounds good but not here. Melz, Sylvania’s, 6FG8’s, are much preferred.

@dlcockrum I would not say the Linlai E-6sn7 has “Weaknesses” they are just subtle differences that I felt a few Nos tubes provided that I preferred.  The Linlai’s are really an excellent new production tube. No Tung Sol’s RP’s for me just too pricey for their performance review.  Looks like I am done adding 6Sn7’s.  I feel I have hit most of the key good 6SN7’s and have a good selection.  Selling off ones that just aren’t special to reduce collection.  It was a fun experimenting on my own system.  

@tksteingraber Thanks for the thorough description of your listening impressions of the Linlai E-6SN7 tubes. Sounds like a good tube overall yet probably not one I want to add to my stable based on the weaknesses you noted.

The 1982 Melz 1578s have settled in very nicely as they accumulate more hours. I definitely place them in my top five. Still a touch forward in the upper mids but no longer objectionable. Their superb soundstage and bass continue to impress and, despite their reputation, one of the quietest tubes I own.

What’s up next for you? Perhaps a pair of Tungsol 6f8g round plates?

@dlcockrum my light bulb E-6SN7 LinLai pair arrived and have 80+ hours on them now.  When I first played them they sounded quite bright with a booming bass and recessed dull midrange.  I was ready to send them back but read they needed 50-100 hours break-in for them to come to life.  On my system and my ears the LinLai  tubes have improved noticeably with break-in hours.    My assessment pretty much matches some of the other thread postings out there.  The Good:  excellent clarity, quiet, nice instrument separation, wide soundstage, fantastic tight clear deep bass. The not so great: treble on the bright side, soundstage is wide but flat lacking 3D depth, midrange just lacking a bit - just missing that full resonating sound.  Overall this is a very nice new construction tube.  I feel the LinLai’s had a Solid State kind of sound or digital vs analog analogy when compared to NOS.  I would highly recommend them for amp builders and anyone who doesn’t want to get into the NOS tube intricacies.  I could be very happy with this tube but I still prefer my NOS ‘50’s Melz, Sylvania GTA chrome domes, 6fg8’s.  I do like them better than Sylvania vt-231 and Ken-Rad black glass vt-231’s which I feel are a step down from the others listed.    Granted this is just my opinion, on my system with my ears and preference for the warmer tube so take it as such.  I will continue to give them more playing time.  They are definitely keepers and I will enjoy them for a different flavor choice.  

 

@tksteingraber 

I have read that it’s closer to 50% of them are noisy/microphonic. That’s pretty good odds of getting bad tubes. You really need a competent and honest seller if you are going to buy them. 

@dlcockrum ok update on Melz noise issue. Seller told me 30-40% of these older Melz tubes have noise issues due to old tin solder in the pins. He told me to heat each pin with a solder iron and get them hot enough to repair internal joints. He said it rarely doesn’t solve the issue. I got my solder iron out and the noise is gone now👍! Time will tell if the noise stays away🤞. These tubes paired with my DAC 1974 Reflector 6N23P Single Wire Silver Shields is beyond what I thought my modest system had in it. They just sound better in every way with zero fatigue. I am truly surprised the impact tubes can make.It is going to be hard to switch them out but each tube has its pro’s and cons.

@tksteingraber Thanks for the feedback on the 50’s Melz tubes. I find your observation regarding the constricted soundstage interesting. My 1982 1578 exemplars excel at soundstaging IMO. Perhaps a loss of some soundstaging is the price one pays to get the reputedly more balanced midrange of the 50s tubes?

Apparently it is not uncommon for the early Melz to have noise issues. IIRC there is a tutorial (on head-fi.org?) for resoldering the pins on Melz tubes that has been reported to yield positive results in many cases.

Regarding the upper-midrange prominence I was experiencing early on from the 1982 1578s, I ran the ISOTEK break-in/conditioning track several times and it seems to have further reduced this. These tubes are sounding very good now, but I still perceive that, despite the strengths you denote in your post above, they lack the musicality and emotional engagement of the NU 6f8g’s or the TungSol VT-231s. More time will tell…

I am interested in hearing your feedback on the Linlai Elite.

@charliee ken-rad 7193 sounds interesting but I need less choices not more🤪.  For $165 for a pair I am willing to give Linlai-E’s a go.  I have not heard that these Linlai-E’s have had short life issues?  Several well respected Amp makers now use them with glowing recommendations.  Anyone experience issues with Linlai E’s?

@Linlai Elites E

$354 delivered for a pair of chinese tubes? Oh hell no. Plus, chinese tubes are notorious for short life span. Good luck with these. 

Interesting thread. I have been a 6SN7 enthusiast since around 2003. After owning and using all the better versions in that time, I have finally stepped off of the 6SN7 merry go round and settled on my latest find. I am now using Ken-Rad 7193 with adaptors. 7193 is half of a 6SN7, same as the 6J5. They differ in that the 7193 has the anodes on top like the 6F8G. My adaptors are made by a guy in Bulgaria who point to point wires them as opposed to the circuit board type from china. I found a U.S. source for the Ken-Rads who has a huge supply of them, new in military box, and they are only $8 each. So at $32 a set I'll take them all day long over the stupid money people charge for 6SN7!!

@markusthenaimnut obsession what obsession 😳. Don’t miss out on 7n7 with an adapter 🤪

@shkong78 got it and respect your decision to have us discover 6f8g’s on our own. Cheers! 

@dlcockrum ‘56/53 Melz arrived today.  Both tested closely matched and 100%+.  They sounded wonderful in all areas but  the bass, mid-bass and details were the best I have experienced.  The only area it may not be the best is the soundstage seemed focused and didn’t fill the room as other tubes do. The only problem is my fear of noise appeared.  The ‘56 tubes sputters quite frequently.  We’ll see if it works itself out but it will probably be taking a return trip back home.  Fyi- I cancelled the Ken-Rad 6f8g’s and ordered a pair of Linlai 6sn7-e’s instead.

Also, received a quad of Russian Foton factory ‘65 6sn8 black base.  At $30 including shipping best deal to be had.  They are new and test NOS. They sound just as good as any of the Sylvania 6sn7 line except for the vt-231/bad boy’s are more refined.  Russian tubes from Melz, Foton Voskhod and Refector from the ‘50-mid 70’s seem to be very nice tubes.  I have several ‘50-60’s Russian 63ps/6l6’s that are as good as any tubes.  Time to turn off the ebay/paypal line of credit🤣

Fun to revisit this topic.🤪

And just to add to our obsessive collecting horizons, may I remind you all that the predecessor of the 6SN7 was the 6J5? A 6SN7 is basically two 6J5s in one bottle and the change was made to simply reduce costs. Mick Maloney seems to acknowledge this by offering a uber-preamp which uses vintage Navy 6J5s instead of 6SN7s...

Those who research obsessively will find a thread (somewhere - I don’t remember where it is right now) in which the claim is made that the best 6SN7 is a pair of 6J5s...! A whole ’nother domain for tube obsession insanity. 😉

I think it’s interesting that Don Sachs is using the new Linlai Elites in his preamp and they were also selected for the new 300B amp discussed by Lynn Olson and others on the "300b lovers" thread.

Me, right now I keep coming back to the old KR VT231s. But there’s a lotta’ great sounding tubes out there. Haven’t tried the Linlais yet. Also haven’t tried the 6F8G tubes with the adapter yet. But it’s in the back of my mind to do so. 🙃

I do not intend to give detailed comparison of 6f8g tubes.

 

As soon as I do it, price of some tube will be jacked up.

 

Some 6f8g tubes are available under 120$ per pair, thus one had better find out.

 

It is like wine tasting.

@shkong78 I really appreciate your thread.  It has been so helpful in identifying tubes I may not have known about like the 6fg8’s.  Can you share which  6fg8’s you like.  I have 2- the NU round plates and Rca early 40’s gray glass us navy tubes.  Both are excellent with different flavors.  Thanks

@paul_lindemann

 

I have 5 pairs of Sylvania vt231.

 

They are great but with too tight midbass.

 

If your system is bass rich, they may work well.

I also have two pairs of Kenrad vt231, thus agree your opinion on it.

 

Kenrad may do wonder with somebody's sytem with rather analytical balance.

 

I have 80 difierent kinds of 6sn7 and variants including 10 different kinds of 6f8g.

 

After going through all of them during last 4 years, I reached the conclution that there is no best one.

 

There are some top tier groups but they also need system matching.

 

Thomas

Alot of great 6SN7 types out there!

 

To my ears the Ken Rad - although a great tube with the best bass, has the weakest midrange and treble.  The Metal based Sylvania sounds amazing for the first couple hundred hours, but the pixie dust wears off as the tube starts to age.  The Raytheon flat plates are fast, dynamic, clean and exciting - but lack any midrange texture and warmth.  The RCA VT231 and 5962 both have the warmth in the mids, but are not as transparent.

The best tube overall, in a neutral system is the VT231 Sylvania.  Bass establishes a great foundation for the music, midrange is the best I have ever heard from a 6SN7 type, and the treble is clean and extended.

 

Yes, those are the ones I bought @tksteingraber.  The lettering on both pairs of mine are horizontal, just like in that link. However, I got mine from an diff seller: atop authentic auction. I also bought a quad of the  Linlai WE 300B from them. They are solid sellers.

@1markr thanks for your input.  I remember these being recommended a year ago or so.  Are these the ones you have?  Thanks

https://www.ebay.com/itm/284943359892?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=heHyMkH-Re6&sssrc=4429486&ssuid=2lFcSwP8SgS&var=&widget_ver=artemis&media=COPY

@1markr Thanks for the input on the Linlai Elites. I researched those a year or two ago and got lost in the endless back and forth forum chatter about which ones were the good ones (Horizontal or Vertical lettering, etc) and whom to buy from. Can you tell us exactly which ones you have (or better post a pic) and whom you bought them from?

I too have been a big fan of the NU 6f8g round plates, and I have been using them for quite a while. However, recently I have rolled in the Linlai Elite 6SN7s, and they are fantastic tubes, worthy of replacing the NU 6f8gs in my rig. I find the Linlai to have have better transparency and air, resulting in a more holographic soundstage, but they don’t do this by sounding brighter or etched, and the midrange stays very natural. They are a touch more forward sounding than the NU, but I like that. Other improvements over the NU - tighter bass, much, much quieter, and not microphonic (like the NU usually are). 

@tksteingraber Please let me know how you like the early Melz and the KR 6f8g.

@dlcockrum thanks for the detailed Melz summary of your experience.  I got lucky andc ordered 2 used Melz with test results in 90%’s.  1-1956 and 1-1953 due to arrive on Tues from Ukraine.  They are the non hole version and the picture shows black shiny plates.  We will see what arrives🤞.  My concern is noise and test results.  I have a tube  tester so we will find out.  Should be fun.  I have really been enjoying tube hunting and rolling🤪

@tksteingraber Glad to hear that you are enjoying the NU 6F8Gs. They have a very special blend of sonic attributes that I find impossible to beat.

The 1982 vintage NOS Melz 6n8s/1578 tubes I bought recently are sort of a mixed bag sonically. Extremely quiet (none of the crackling I read about) with the best bass slam/texture/definition I have heard (I prefer their bass to that of my KR Vt-231s) and unequaled imaging/soundstaging. Transparency is on par with my Tung Sol VT-231s. Upper treble is smooth and refined. Unfortunately, they are very forward in the upper mids, thus fatiguing after just a short session. They have improved in this area with additional play, but so far the upper-mid forwardness largely remains.

There is a ton of discussion on the Melz over on head-fi.org. Members Paladin79, bcowen, and JKDJedi seem to be the foremost experts on Melz. IIRC they feel that the Holy Grail Melz 6n8s is the early/mid 1950’s non-hole shiny black plates with the same micas and metal supports as the later 1578s. Good luck finding those at this point!

@dlcockrum my 6f8g adapters arrived and I was able to listen to my NU 6f8g branded Raytheon round plates. All I can say is they really are special in my Supratek pre. They are just better in almost every way. Definitely the best tube I have heard. Also, I was able to listen to my RCA USNavy gray glass ST bottle 6f8g and they are really nice tubes as well. Second best tube. The Rca loses some detail/transparency but has such nice warm tone. A more relaxed tube you can listen to and not tire. Also, it is less focused with a larger soundstage.

So far here is my list of tubes in order of preference.

NU branded Raytheon round plate 6f8g

RCA USNavy gray glass ST bottle 6f8g

Ken-Rad black glass vt-231

Sylvania vt-231

Raytheon vt-231 (both Nos tubes became noisy and had to return=done with them)

Rca gray glass 6sn7 (early ‘40’s same as vt-231)

Sylvania 6sn7wgt brown base

Sylvania 6sn7gta tall boy chrome dome

Sylvania 6sngtb medium bottle chrome dome

Raytheon 6sn7gtb side getter

Rca 6sn7gta

GE 6sn7gtb

On order to try: Russian 1956/1953 Metz 6n8s, Russian Foton 1962 6n8s, Ken-Rad 6f8g staggered plate

 

 

 

 

 

@tksteingraber

 

Raytheon sounds most brigh and detailed.

 

On the other hand, NU sounds full or dull.

 

Sylvania and RCA are in the middle.

 

Tungsol is also in the middle but overpriced due to some hype.

There are GE or other minor labels which sounds also middle.

 

i had collected more than 10 different labels but they sound different.

 

I am collector of vintage tubes for fun not for business.

 

Thomas

@tksteingraber i was fortunate to buy two of the Phillips rectifiers back when they weren’t so pricey. Perhaps someone else on this thread can recommend another rectifier with similar sonics. For now, just see how you like the KR and NU with your Mullard GZ34…

I have not yet heard any other 6F8G tubes in my system. It is sometimes said that the other 6F8G’s (TS, Raytheon, etc) sound very similar to their 6SN7 counterparts with the NU being the exception, but I do not have first hand experience with the others.

I found this 6F8G thread informative: https://www.head-fi.org/threads/6sn7gt-6f8g-an-exploration-of-wwii-era-octal-tubes.890205/

Unfortunately, as always seems to be the case nowadays, the 6F8G models the author most prefers are unobtainium now (KR round plates and Raytheon dark glass flat plate).

I just broke down and ordered a pair of NIB/NOS Melz 1578s (the real ones $$$$). Will let you know what I think.

@dlcockrum thanks…that Phillips 5R4GYS is next to impossible to find and big💰.

Not sure my modest system is worth it and would benefit much from it.  I will keep it in mind though.  Have you tried other 6F8G’s? Other good ones in case I want to have other choices? 

@tksteingraber IME, the KenRad VT-231 and NU 6F8G can sound a little closed in (lacking air and sparkle on top) with the Mullard GZ34 rectifier in my system. If you find that to be the case after becoming acquainted with them in your system, try a more lively rectifier like the Phillips 5R4GYS.

Another can of worms?  Anyone try mixing different styles of 6Sn7’s with success. I had a Raytheon vt231 T-plate that lost it’s partner due to bad noise.  On a whim I had just received one of my Ken Rad vt231 black glass and wanted ti try it out to make sure it was good and noise free.  Both tubes tested over 100% closely  matched.   Fired them up and  not expecting much but was  shocked how good it sounded.  Best pair I have rolled so far.  Looking forward to the second KR.  

@dlcockrum @shkong78 ordered a pair of Nos/Nib National Union 6F8G round plates and adapters.  They are branded Raytheon with identical construction as NU. I am using a Mullard GZ34 and Rca 6l6 bottom getter blackplates in my Supratek pre. Should be fun🤞

@dlcockrum Great info many thanks!

@tksteingraber I have found that the National Union 6F8G round plates are very special tubes in my Supratek Syrah. I also have the NU 6SN7 round plates and the NU 6F8G sound better in every way. Also have Tung Sol VT-231 round plates (transparency kings), KenRad VT-231 staggered plates (bass kings), Sylvania T-plates, Baldwin flat plates, Sophia Electric, and Shuguang Treasure CV181-Z and the NU 6F8Gs are my “go to” tubes.

Keep in mind that the Supratek power supply’s rectifier tube paired with the output tubes has a significant influence on the sound (I like the Phillips 5R4G rectifier with NU 6F8G while the Mullard 5AR4/GZ34 Fat Base rectifier pairs better with the TS round plates IMO), so some mixing and matching of rectifiers is important.

Re: Raytheon 6F8G T-plates vs flat plates, the T-plates are much easier to find but the flat plates (scarce as hen’s teeth) are said by many to be significantly superior sonically.

@tksteingraber 

 

6F8g tubes tend to sound fuller than regular 6sn7.

 

Thus it may depend on your system and taste which one to choose.

 

Thomas

@shkong78 Thanks for your response and recommendation.  Can you give me your opinion on how the 6f8g compares to the 6sn7?  Is it worth the plunge?  Selection is pretty limited driving prices.  
Tom

@tksteingraber

I agree with you that vintage tubes are like vintage wines.

 

There is no best one but they have different flavor.

 

I recommend you to get 6f8g tubes from Ebay.

 

Tungsol got overpriced, but you may get RCA, Sylvania, National Union or Raytheon 6f8g  at reasonable price if you keep searching.

 

You need adapter which is also avaiilable at Ebay.

Good luck!

Thomas

@shkong78 Thank you for sharing your tube obsession with us it is very helpful and enlightening. I am just starting to get into tube rolling with my new Supratek Cabernet preamp and these tubes are just like red wine. The more you try the more you want to try more. Is there a best? Absolutely not. It’s so system and personal taste dependent but your list is such a helpful starting point. So far I have tried RCA ‘40s Gray Glass $70, RCA GTA $28, Radiotron ‘40s Aussie ( came with amp 1 died day 2), Raytheon side getter $26, Raytheon VT231 $100 (1 noisy had to be returned searching for replacement), Sylvania Brown WGT $120, just ordered Ken Rad VT231 black $150, GE GTB $15, Sylvania VT231 $120 & GTB Chrome dome short $35, Meltz ‘53/‘56 $100, Russian Foton ‘60’s. $25. Prices listed are for pairs with no plans going for the crazy priced ones. All used and testing 90-100%+ confirmed on my Hickok 605A. My Top 3 so far are Sylvania WGT, RCA gray, Ray vt231. All sound great and very close just slight differences.
I do have a few questions for you if you don’t mind.
1- Which russian black base tube did you get? Reflector, Foton, other? Shape on glass identifies them diamond is foton, shield like shape is reflector and others.
2-Sylvania styles are very confusing so many of them. Which specific ones did you try? Tube size, plate type, getter type/location, years…?
3- Which Ray vt231 is better? T plate or ladder plates? Mine were T’s.

Thanks for sharing your expertise!

Correction: that was a1950's Sylvania 6SN7 pair the broker-friend picked up for $35 on eBay and preferred over the TG's. He thought they were made in the same factory as the GE's.

Before I got the Treasure Globes from premiumtubes.com, my favorite was the Sylvania 6F8G in a Supratek preamp. The guy who bought my Cabernet is still using the TG’s, although his friend who brokered the deal preferred a 1950s CBS pair he had laying around, as I recall. 

For the last three months, I had been using Amperex 6n7 in Line Magnetic 508 SET.

 

After playing with Puron plug in filters,  i switched to RCA vt231 whichs give nice details and sharp focus.

 

Yesterday i had gone back to Melz 1578.

 

Although 1578 does not give nice details and sharp focus.as RCA vt231, it makes sound organic and comforting with less treble overall.

 

The conclusion is that there is no best 6sn7 tube.

 

I keep changing tubes depending on my mood and change of components.

 

I have around 70 different kinds of 6sn7 and vanriants.

 

Thomas

@shkong78, I think we are probably experiencing some price gouging because of the Russian tube situation.  

By the way, dealers had jacked up the price of vintage 6sn7 tubes too much.

I paid 60$ for pair of Sylvania 6sn7 wgt with brown bass 3 years ago.

But now they ask around 200$ for pair of them.

Since I have around 80 pairs of 6sn7 tubes and variants, I will not buy more of 6sn7 tubes.

 

Thomas

Few days ago I replaced RCA vt231 with Sylvania 6sn7 wgt with brown bass (not metal bass) in Line Magnetic 508.

Sylvania 6sn7 wgt give vivid sound with sharper focus while RCA vt231 give more relaxed sound.

It is like wine tasting of vintage wines.

Most of vintage tubes sounds good but with different flavor.

It is up to you to choose specific flavor depending on your taste and system.

As I have more than 60 different kind of 6sn7 and variants, I take turns on tubes depending on my mood.

This is off topic but is there anyone in the NYC/tri-state area that has a tube tester and the knowledge that would be willing to test some of my 6sn7's?

I have various tubes, some sought after but have no idea if they are still strong after years of use. 

If not is there any reasonably priced testers I can buy that aren't too large? I know there are different types of tests, etc.  

I switched from Melz 1578 to RCA vt231 in Line Magnetic 508 for fresh air.

Wow, there is more air floating around Altec A7.

The strength of Melz 1578 is deep and impactful bass, wide and deep soundstage with pure but slightly less treble.

While my Chord Dave Dac sent to AS center for repair, I had been using EMMLab Dac2 which give more organic and impactful sound than Dave.

Dave and Mscaler combo give more details and pinpoint imaging in 3d space.

With Dave and Mscaler and Lansche 4.1, I prefer Melz 1578 to other 6sn7 tubes made in USA.

But with EmmLab Dac2 and Altec A7, I prefer RCA vt231 to Melz 1578.

I may switch back to TS bgrp 2 weeks later.

Although I have 3 pairs of RCA vt231, I have only one pair of TS bgrp which is damm expensive for small input tube.

It is kind of mix and match.

There are no best tubes for everyone.

Vintage audio tubes are like vintage wines.

As some people collect lot of varius wines, I collect vintage tubes.


You may choose a tube depending on system and your mood.

if you try the shuguang black treasure cv181z IMO are like or better than the psvane

I missed also on the we6sn7, apparently great tube

@highstream 
I'll be curious to read your thoughts after you play around with the tube rolling in your Supratek when you return to the stock tubes from Mick. I have really enjoyed tube rolling in my Cortese but could easily live with the preamp outfitted with the stock tubes.  They're really good and strike a very nice balance with all the important characteristics I look for when rolling tubes. 
Right now I tend to roll between CBS 5692s and Ken-Rad VT-231s. Only because I'm too cheap to step up to the Melz 1578s, the Psvane CV181s and I missed out on the Shuguang WE6SN7 plus tubes with the extra tall glass.
 I've got a lot of love for the 6SN7 and the Supratek!

If I could still edit my post, I’d note that the 1578 is highly rectifier dependent, at least in my set up. I’ve now tried three— potato masher, Fivre and Brimar 5R4GY’s with increasing warmth and presence, although w/o entirely overcoming the emotional distance that dryness gives the sense of. 

My search for a pair of 6SN7/6F8G’s for a Supratek Chardonnay preamp continues. I’ve tried the Shuguang WE6SN7, early and late ‘50s CBS Hytron’s, and wartime National Union and grey glass Sylvania 6F8G’s. Of those, my favorite are the Sylvania’s, which offer a fine mix of sonic features I like, including a moderate degree of warmth.

Today I’m about 10 hours into a pair of genuine metal base NOS Melz 1578’s, sold and given initial few days burn in by someone in the States who had collected quite a few, resoldering the pins to ensure the best sound and long life. I have to say that this pair has great clarity, good tonal accuracy and a very nice sense of rhythm. Playing the old (1994) Sheffield/XLO Test and Burn-in CD, the 1578 renders the Doug Sax/Roger Skoff stage walk-around the clearest and most realistic I’ve heard over the years. However, what I haven’t heard yet is a sense of life or “alive.” I would characterize it so far as dry, uninvolving, boring in the sense of the music just passing by when not paying attention to the other characteristics (which I prefer not to focus in most of the time). Similarly, in the 6SN7 double blind shootout posted on Audio Head, three of the four panel members characterized the Melz as “dead” (the three liked the wartime grey glass RCA GT the best). Will have to see what develops, although “life” is not usually something that develops with burn in, but is either part of a tube’s DNA, or not.

for the price of these tubes they offered a more tube sound than the new JJ Tesla 6SN7 tubes I was using.  More musical, more dimension, a nicer more relaxed sound in direct comparison in the preamp.  Have not tried them in my hybrid tube power amp yet or to the many 6SN7 tubes I already own.

Thanks. It looks like they come from extra stock or liquidated Old Chen preamp stock. See https://www.hifi-amplifiers.com/en/oldchen-tube-amplifierslaochen-c-118/oldchen-c1-hiend-6h8ccv181se...  gd-parts link for the tube goes to AliExpress, where they show 1000 pairs,

@highstream

Check out this link http://psvanetube.com/wordpress/which-6sn7se-should-i-get/