which 6sn7 tube for my wyetech topaz amp

I use an RCA smoked glass and really like it, more on the romantic side but leaves no detail out. I use it in my dehavilland.

For what it's worth, I agree completely with Peter. RCA 5692 is the best I've tried with Sylvania 6SN7 GT a semi close second choice.

RCA is more dense, sightly better dynamics and beautiful “flat" top end. Sylvania will be ever so slightly more extension which may or may not be desirable depending on tonal balance of entire system.

Of all the 6sn7's I have and I have most of them, I always go back to the sylvania 52 bad boys in my preamp. The red base 5692 are also very nice.

In your amps it could be a different tube, but these two are a good place to start.

If you value sound stage depth & width(excellent ambiance recovery), neutral reproduction(no phony warmth/tubey editorializing) and fast/accurate bass; either the 1940's round plate Tung Sol 6SN7GT(JAN CTL) or Sylvania 6SN7W(JAN CHS, TALL BOTTLE ONLY, metal or Bakelite base) tubes are phenomenal. The Sylvania possessing a bit more bass slam. Either choice will cost dearly, but- are worth every penny, IF you value faithful music reproduction. The 1940's, BOTTOM GETTERED, Sylvania(JAN CHS)and Ken-Rad(JAN CKR) 6SN7GT/VT231's are next in the accuracy department, with just a bit less depth of sound stage. Just as beautiful everywhere else. (http://www.ebay.com/itm/Pair-Awesome-Sylvania-JAN-CHS-6SN7GT-VT-231-T-Black-Plate-Audio-Tubes-/111720481029?pt=LH_DefaultDomain_0&hash=item1a030f4105) (http://www.ebay.com/itm/Matched-Pair-of-SYLVANIA-6SN7W-CV1988-B65-ECC33-Metal-Based-Tube-NOS-NIB-274-/291488621829?pt=LH_DefaultDomain_0&hash=item43de136505) (http://www.ebay.com/itm/TUNG-SOL-ROUND-PLATE-BLACK-GLASS-JAN-CTL-6SN7GT-VT231-Amplitrex-Tested-1264006-/191608860512?pt=LH_DefaultDomain_0&hash=item2c9cc72f60) (http://www.ebay.com/itm/Pair-Matched-Ken-Rad-JAN-CKR-6SN7GT-VT-231-Military-Spec-Vacuum-Tubes-ECC82-/371378091687?pt=LH_DefaultDomain_0&hash=item5677dbf6a7) for example

BTW- Note the metal strip construction(top supports) of the
Tung Sols. I've not tried the round mouse-eared or
round mica types, so- can't vouch for them. Also- the short
bottled Sylvania 6SN7W was terrible(IMO). Way back when; I
tried the top 12 tubes on this survey:
(http://www.dehavillandhifi.com/6sn7_vt.htm) What I've
stated above, is what I found.