SLI-80 which 6SN7?

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,
Jacob

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!
Jacob