had good luck myself with sylvania c1944 vt-231s--crisp, clear, musical without harshness. best inputs were siemens cca, fwiw.
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Go to Vacuum Tube Valley [www.vacuumtube.com] and get the back issue number 11 from the spring of 1999. Most of this issue is about the 6SN7 and while parts of it are over my head, there is a very nice one page article which lists and rates over 20 6SN7 tubes. I have used a few differant Sylvania 6SN7s in my AES(cary) AE3 preamp and am very happy. They rate 3 differant Sylvania's and two differant Tung Sol's
I don't have a cary, but I do have a tube preamp with 6SN7's. Generally I have found that I prefer the 1940's era tubes over later iterations. I also prefer bottom-getter 6SN7's over top-getter types. There are 4 6SN7's in particular that I would recommend. 1) Sylvania VT-231 1940's, 2) Sylvania 6SN7GT tall-boy similar to VT-231 construction but with green lettering on the base, 3) Ken Rad 6SN7GT/VT-231 black-glass 1940's, 4) RCA 6SN7GT/VT-231 grey-glass 1940's.
Unless your preamp is a push/pull configuration there is no need for tube matching. Most "matched pairs" aren't really matched anyway.
First, I would recommend that you try to match tubes between channels where possible of course. For most tubes, these differences are unfortunately not subtle.
As for sylvanias, I currently own vt231 (chrome base), two kinds of chrome domes, and the W type in both plastic and metal bases. The Ws are by far the most refined for my tastes (metal base or not), followed by the vt231. Those three are far better than the other sylvanias in the systems I've looked at. The Ken Rads are impressive, but the Tung Sols, Brimars, and NUs are all must-hears in some systems too. The RCAs (gray or variants) can be quite nice too depending on your tastes.
Which one will be the best for you depends of course on system synergy and your tastes. If you give me some idea of your priorities in preferences (soundstage, "natural" tones, pacing, etc) and some sense of your preferred tubes elsewhere I can make a few suggestions.
There are several TRUE 6sn7 gurus in audiogon. With any luck, they will chime in too. I have about 12 good matched quads of different brands and types but am still looking to add a few missing keys, so can only tell you within the ones I own... There are 4 or 5 guys I know here who would base their opinions on many more types spread over many more years of listening, so I would suggest you list your preferences for sound and music here as well as a list of the rest of your other equipment and which tubes you have preferred in that equipment. I know it is a bit of a hassle but you will get better help that way...
Best of luck,
WOW! Lot's of input! Some very good info!
As far as my choice of music? Mostly Jazz along with some classical, contemporary, and vocals. I prefer a sweet midrange with silky highs, good bass of course is a plus. But midrange first. I was thinking of trying some NOS EL34's Siemens or Mullard. Also I plan to try some Sovtek KT88's, Svetlana 6550's and if I get real brave I will try some NOS 6550's
I have an old CAL Icon MKII I picked up for a song I will use as a source. Maybe later I want to add a Sonic Frontiers DAC. I'm sure once I add the DAC everything will change. But for now I want to experiment with a few tubes. I have never listened to the 6SN7, but am quite familiar with the 6922. I prefer the Telefunken, Siemens, with Mullard running 3rd. I should say that most of the 6992's I have been exposed to are form listening to my tube rolling friends system.
I have a pair of Hales REV 2's, but may switch to a Meadowlark Kestrel, or Shearwater if I can get a good deal on a pair. I have always been curious about these. I am currently running Kimber 8TC for the speakers, and Nordest Red Dawn for IC's. Of course all of the cables could change with time. This is pretty much " try this, try that " system at this point.
hope this helps!
Thanks - Based on your preferred tubes for 6922s in particular I would guess that the Sylvania 6sn7Ws would be your gold standard (make sure same structure as the metal bases though they need not actually be metal bases). Amazing top-to-bottom performers with exceptional soundstage. On the cheaper side, you may want to try the RCA grey glass or even the little RCA 5692 tubes which have a tonal palette in line with the tubes you seem to like.
Some of the others I previously mentioned like NUs are probably not going to be your ideals since they are extremely rich in tone rather than covering extension as a primary strength.
This should be a fun process for you. The 6sn7s are a lot of fun to play around with. Once you get going, email me and let me know what you think (if you remember!). If you need recommendations for trustworthy and encyclopedic 6sn7 audiogon members and tube guys, I would be happy to suggest a few too.
Best of luck!
I own this amp and have tried MANY different tubes in it. To some extent the choice of 6SN7s will depend on the other tubes being used. That said: I have tried many of the exotic 6SN7s in this amp. Sylvania metal base Ws, black base Ws, 1940s era Ratheons, black glass Ken-Rads and Tung-Sols, 1950s GE GTAs. They all imposed themselves on the sound. Some had nice mids but no upper or lower freq. extension. Some sounded warm and fuzzy. But so far, the best tube for THIS amp that I have found is a late 1960s FAA issue Sylvania GTB, the one with the angled plates. If you want clean, extended and detailed sound this tube is hard to beat. It is the most neutral and natural sounding tube in my set-up. I don't know if the FAA tubes were specially selected or not. Maybe all Syl. GTBs will sound the same. Haven't tried them since I have enough of the FAA ones to last me. Other tubes I am using currently: USA Amperex 'pinched waist' 6922s; GEC KT-88s; Mullard 5AS4s (RCA 5U4GBs make this amp sound hard and very bright; so much so that when I ran them I was forced to use Mullard 6DJ8s to soften the top end).