Black glass KenRad 6SN7s take the cake

KenRad black glass are extremely fine. I have four NOS 1944 matched pairs, army boxes, that I am still glad I accumulated at the time. I use the Tungsol round getter black glass, but only because speakers in that particular system are not full range (Tungs sound sweeter there, although not as expansive as Kens).

You guys may want to take a look at the "Preamp of the Century" thread. The Supratek pre takes 6SN7's and we discussed them there about a month ago. My impressions and others are there FYI.

denis, what tube did you eventually end up with as outputs on the 70/70? Svets? Happy?

Ken Rad Black glass discernibly better...Huge depth, expansive, quieter, low level detail more natural, harmonic decay improved, Homeric bass, even more organic while still clearer into depthfield without any increase in sterilty. Sounds very similar in all parameters - as you would expect - but involve-ability is heightened, making any deficiciencies at the frequency extremes (full toward plummy bass in some systems; slight rolling at very top but not thin, just reduced projection) a non-issue IMHO.

Gunbei, YES! The increase in qualities is exactly that. I didn't say so because my experience with the Slv is less (I have 3 NOS matched pairs but once the KenRads went in, I didn't spend as much time with them as I normally would have) and, also, people start thinking you're a Mister tube-know-it-all if you go around splitting hairs that much, which becomes counter-productive to the discussion.

IMO Black glass Ken increase is even more evident than that from clear Ken to Syl VT231. In quanititative terms - if you were going to point to all the audio language we use - then the increase seems continuous and of the same fabric (and it is...). But in qualitative sense - how you react to the sound, whether "musicality" increases, whether the change catalyzes one to "let go" of thinking and sink into the music - I think with the black Ken the curve becomes increasingly progressive.

bwhite is correct, although the system he constructed is allowing him to hear the differences more than most would :0)[his Supratek pre having a lot to do with it; happy now bwhite?]. Basically, in our language terms, tons-o-air and stretching back into large, voluminous depth field that offers the simulcrum of infinite dissipation of harmonics (er, our reality is infinite, so having that quality simulated is, er, a good thing; as opposed to bounded space which is not reflective of whats "real"). Highs sweeter, much more pure, distortive noise floor lowered revealing low level nuance, but not at expense of denuding space into a sterile void (also not a "real" experience, and what most people in the "accuracy school" refer to when they say their noise floor has been lessened). Space is lush and pressurized. Bass, while somewhat plummy in comparison to, say, the precision of a vintage Brimar, is homeric in proportion and how drums sound subliminally real (see, Braveheart and Gladiator CD's for this). Can impart feeling of longing into intruments and performances when it is there. Breath transients contain wetness; chest has volume; cellos have body (major difference with Syl VT 231, also reflected in highs, although I would not characterize them as "thin" in an harmonic sense, but lacking the same projection characteristics as the remainder of the spectrum, and further as you go up).

Got you drooling yet?

Yes, I'm talking about the mil-spec circa 1942-44 "VT231" black glass Ken Rad.

You know, it just occured to me that I'm not doing myself any favors on getting some of these in the future...

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?

twl, I thought about "synergy" on pre input vs. amp output, but concluded that was a red herring because, theoretically, and in my gut, I feel the pass through on the berning should be best - or at least good enough for you to base a broad opinion on the tubes versus each other.

Haven't looked at my SylVT231's in a while, but I know they are NOS in army boxes with original packing from 1942, so assumed those were the good ones...

If your WGT are different, I am, of course, intrigued; always looking to learn something.

On the metal base, I never wanted to pony up, but a few who did with the Supratek thought they were not what everyone has said. Maybe the rep comes from pro guys, or the Glass Audio article a few years ago, but people's consistent reaction, coupled with the cost, made it easier for me to back away.