Shootout of Nos 6sn7 tubes

@tksteingraber i was fortunate to buy two of the Phillips rectifiers back when they weren’t so pricey. Perhaps someone else on this thread can recommend another rectifier with similar sonics. For now, just see how you like the KR and NU with your Mullard GZ34…

I have not yet heard any other 6F8G tubes in my system. It is sometimes said that the other 6F8G’s (TS, Raytheon, etc) sound very similar to their 6SN7 counterparts with the NU being the exception, but I do not have first hand experience with the others.

I found this 6F8G thread informative: https://www.head-fi.org/threads/6sn7gt-6f8g-an-exploration-of-wwii-era-octal-tubes.890205/

Unfortunately, as always seems to be the case nowadays, the 6F8G models the author most prefers are unobtainium now (KR round plates and Raytheon dark glass flat plate).

I just broke down and ordered a pair of NIB/NOS Melz 1578s (the real ones $$$$). Will let you know what I think.

@tksteingraber

Raytheon sounds most brigh and detailed.

On the other hand, NU sounds full or dull.

Sylvania and RCA are in the middle.

Tungsol is also in the middle but overpriced due to some hype.

There are GE or other minor labels which sounds also middle.

i had collected more than 10 different labels but they sound different.

I am collector of vintage tubes for fun not for business.

Thomas

@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🤪