Black glass KenRad 6SN7s take the cake

There's a long, thin, clear drool sling attached to the left corner of my mouth making it's way to the floor. :•)

Give me the Sylvania 1940s 6SN7 WGT any day. IMO the best there is. If you really want to hear what a 6SN7 can do, just listen to it as an output triode in a Berning Micro ZOTL, driving a pair of Lowthers direct. This is where you really hear the soul of the tube, with nothing between the tube and the speaker but a few feet of wire. Nothing after it in the circuit at all. Pure 6SN7 coming out the single drivers. The Sylvania does it all. I swear I can tell when Rickie Lee Jones casts a quick glance at the band and smiles as she says, "Chicken in the pot, Chicken in the pot" on Danny's All Star Joint. Now that is seeing into the music. You can actually tell she's smiling because of the slight affectation of the vocal, caused by the smile shape of her mouth as she sings it. I'm not kidding.

twl, now I'm smiling. :0)

Question though: What were your comparitive observations - the differences between the Syl VT231 and the black glass Ken-Rads - when you put them both in your newly arrived amp?

Asa, I did not use the 231, I used the WGT version. And the sound difference was amazing. The observations made by others regarding the delicacy of detail, midrange liquidity, strong bottom end, crystal-clear high end were all there, far better than any other tube I've used in it. Now perhaps with preamps, where it is combined with other circuits, and passed through a power amp on the way to the speaker, there could be some "synergy" considerations that I didn't encounter on my system. The Berning MicroZOTL is the only amp ever to use a 6SN7 as an output triode, as far as I know, and it uses it in a push-pull arrangement with each 1/2 of the twin-triodes inside the single glass envelope performing the push-pull functions. Linearity is excellent with this configuration, and gives teriffic frequency extension on both ends, and of course, no output transformer to saturate or cause hysteresis problems. Now, as I stated, this is a different application of the tube, but I did not get as good overall sound from the Black Glass KenRad in my application, although it was very good sounding with them. The KenRad, Sylvania WGT, GTA and GTB, RCA Black Plate 5692, all were far superior to the stock Sovteks that came with the amp, and would all be a big improvement. I was more disappointed with the 5692 than anything, as it was well balanced, but did not have any real "twinkle" like these others had. And there is a definite difference between the Sylvania stuff, as the years went by. The older is decidedly better, and after the 1st couple of years of the GTB, it was a bad downhill slide. The 6SN7 W and WGT from the 40's are the best, and then the 50's, and then the early 60's chromedomes in the GTA version, and finally the early GTB. Later GTB were not nearly as good. I have not tried the very early metal-base version, although I have heard they are very good. I also did not try the Clear Glass KenRad. As they say, YMMV, and this is only my opinion.

Twl- Have never seen a "black base RCA 5692." The red base
RCA 5692s that were used in my MFA electronics(preamp & amp front end) had plenty detail.

Very interesed in your speaker system. Where can I get
details on the drivers and cabinets?

Aloha.