Shootout of Nos 6sn7 tubes

@tksteingraber IME, the KenRad VT-231 and NU 6F8G can sound a little closed in (lacking air and sparkle on top) with the Mullard GZ34 rectifier in my system. If you find that to be the case after becoming acquainted with them in your system, try a more lively rectifier like the Phillips 5R4GYS.

@dlcockrum thanks…that Phillips 5R4GYS is next to impossible to find and big💰.

Not sure my modest system is worth it and would benefit much from it.  I will keep it in mind though.  Have you tried other 6F8G’s? Other good ones in case I want to have other choices? 

@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