Shootout of Nos 6sn7 tubes

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

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).