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6SN7 some good some bad

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I'm sure if you are a fan of the 6SN7 tube you have discovered your favorites by now. Everyone has a favorite brand of tube.


My recent Russian purchases...

The 1578 has to be auditioned to be believed. It is the premimum

Russian tube of choice and will hold its own sonically with the

5692. They are well worth the money and wait. The cheaper 6N8S

should be avoided at all costs. It lacks clarity, detail, depth, bass,

in short all the good qualities of tubes. They do however made an

interesting paper weight. The only thing I can say in their favor is

that they weren't microphonic in nature.

Got a tube story?
 
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IMHO The Sylvania 6SN7 with offset V style black plates are pretty hard to beat. (My top day to day choice.) Also true of 1940's Jan Tungsol types. The Sylvania types are fairly common on eBay and not terribly expensive. (Yet..) Sylvania types are very distinctive with the V structure and were rebranded and sold by many other vendors.

Early Tungsol when attainable are expensive.. I don't care for the later ones, nor are any vintage GE in my estimation anywhere as good as the Sylvania.

I, umm also really like any Brimar 6SN7 I have ever encountered. Anyone got some just laying around that they wouldn't miss? ;)
These might be the best, it's a toss up between them and the Sylvania in my estimation..

Many like the 5692, these can be quite expensive, late black base ones mostly appear to be standard Sylvania 6SN7 types and should be quite nice. I don't care for the vintage ones I own. (Brand forgotten for the moment.) I don't really get the hype around these, but they may be incompatible with my high voltage design proclivities. :D


The Russian 6N8S sounds pretty crummy compared to any western manufactured 6SN7 I have encountered. (Linearity measurements were worse as well.)
 
I'm using Sovtek 6SN7s. These are quite good: no tendency towards microphony. Giving them a sharp rap does not register any disturbances while o'scoping the output. They also look to be constructed in a robust manner, even including grid radiator "wings" that the US branded types don't have (at least not in the pics over at Valve Museum). In the project where they're being used (cathode follower final drivers) they sound great and work good.
 
This is from an ebay ad................................................

The manufacturer is the Moscow electro tube factory. Special military Development. Was issued by small sets.

The tube is unique that has double marks 6N8S and "1578".

Military marks "1578" means parts similarity inside a cylinder, Microphon effect is reduced to a minimum,

Resource of work - not less than 5000 hours.

The tube is very beautiful.

Date of manufacturing May 1976.


Both the 1578 and the 6N8S are not microphonic in nature. The standard 6N8S does lack the quality of sound that the 1578 has.
When playing a tract off a CD there is a marked difference between the two. The 1578 is a decent tube however.

The standard GE tube is quite good sounding while the newer coin base GE tube isn't worth plugging into a socket.
 
I have to tell you a story.
Two months ago I finished building my 6SN7 amp.
As soon as possible I started it with 2 6N8S tube I had in stock (out of the 8 I have).

And what a nightmare ! It was so microphonic I had larsen in the speaker. I never heard that before with a tube. I started swapping the 8 tubes and found only one which was not microphonic. All of them were OTK !
Finally I ended buying a pair of 6SN7 EH Gold and my god ! Everything was gone. Only purity and clarity remained.
After that I bought a pair of Tungsol Jan 6SN7WGTA from 1947. I must admit they are great and the ones I prefer but astonishingly the EH Gold are very close to them and the ones I am listening to every day (I keep the TungSol for special occasions ;) )

No more 6N8S for me ! I would not even give them to one of my friends.
 
ryssen said:
I know this is not the thread topic ut could you list some god brands of the 6SL7 as well? :)

Again, Sovtek: I'm using these as a LTP with solid state CCS for a phase splitter. The Sovtek 6SL7s are also not microphonic, as sharp raps don't cause any disturbances while o'scoping. Even though I used GE characteristic curves, the design Av= 26.5 and the measured Av= 25. Pretty darn close. So these really are 6SL7s. As for the sonics, I don't believe that you could do any better with those $PRICEY versions that sell for as much as some complete amps.
 
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Usual suspects would apply here too:
Very old GE 6SL7GT with the round plates, Sylvania, Tungsol, Kenrad, all have good versions.

I have lots of Sylvania 6188 which is the industrial equivalent, but to my ear sounds rather strident. Odd as it has cylindrical black plate and is very quiet and non microphonic, should by all rights be a good sounding tube, but IMHO it's not.

The Russian 6SL7 (6N9S?) particularly the 1970's vintage sound very good, I believe Reflektor may have been the factory that made these.

I believe the OTK mark on the envelope indicates that the tube is quality tested to the level indicated by the particular mark, it is not a brand specific mark.
 
Some experiences also qith 6SN7 family

Recently purchased a few types of 6SN7's to roll and try etc.
here's my findings to reports, of course my amp uses 2 12AX7 as inputs, 4 x 6SN&'s for phase spliters and soemthing else I can't tel i imagine preamp part and then the final is a quad of KT-88 or 6550's type dual mono design.

Tried initially CHinese Shuguang 6SN7's thoug tehy're not horrible easily bettered by the Reissue Tung Sols Reflektor made.
then tried Sets of NOS Ken Rads black plates adn everything took a different diemnsion but a litle too mch bass, alsot tried Sylvania's 1950's green labels and red labels Motorla (SYlvania OEM) though they're very good don't have quite teh detail of the KenRads adn only bettered by the RCA's in fact I have now in tehre 1 pair of RCA's gray glass 1940's and 1 pair RCA's clear glass short bottle very very transparenta nd extremelywell balanced.
I am yet to try the RCA red bases 5692 but I can't afford them.
Also I tried some NOS 6G8C russian army circa 1959 and they have a fantastic sound in my system just a very (and I'm nitpicking here) but very slight glare in the mids that maight even sound awesome in some recording or material, if your room is slighly damped yo might not even notce this tiny glare, my room is very live so every little harshness or top end glare or mids glare is amplfied by room interactions and tthrown back in your face, russian tubes old style are absolutely awesome and very cheap paid $ 25 for a quad well matched.

If I didn't have the RCA's or the Ken Rads these will be my choice even over the Sylvanias.
Just replaced power tubes KT88, for some NOS Tung Sols I fond online and to tell you guys the RCÄs make even more magic and perfect synergy with teh old 6550's they're just unbelievable a killer combiantion indeed.

hope this helps;

Gonzalo
 
my 2 cents:

I'm selling Russian tubes. And if you are looking for really good equivalents of 6SN7, ECC32, 6CC10 tubes. I'm strongly recommend looking for 6N8S in METAL Base only. Because they were made for military of Russia and have the best quality. But a little quantity of them you can find in the market.

Oh, and one more things. They're must be with holes. (5 holes on each side)
 
<<I believe the OTK mark on the envelope indicates that the tube is quality tested to the level indicated by the particular mark, it is not a brand specific mark.>>

In the soviet system OTK# in a circle means this (any) product has passed the qulity control by the quality inspector, who has that stamp (number assigned to the inspector).
This is the lowest (normal) quality level in the soviet system.
 
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