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Black glass KenRad 6SN7s take the cake

I've been experimenting with 6SN7s in my VAC 70/70:

ElectroHarmonix: good tube! and great for the price. Much better than I though it'd be, but ultimately sounded too edgy and sterile. Good control throughout, and good detail.

Sylvania VT231: twinkly and brilliant; great detail, tight bass, but much less fatiguing than the ElectroHarmonix; nice and smooth, but still lacking in the mids for me.

TungSol black glass, round getter: better than the Sylvania, in that it was a bigger sound. Lost the twinkly and brilliant quality. Good detail. Good overall, balanced tube. Nothing outstanding I thought, relative to the other tubes I tried.

KenRad, tall, black glass: THESE KICK!! very lush, deep, BIG BIG sound; the absolute best midrange; detail was good, and surprisingly, this tube is NOT DARK. very smooth, and less reserved sounding than the other tubes. Let's it loose... and that's the one drawback; the bass isn't as tight the TungSol or the Sylvania, but it didn't annoy me. What I gained from this tube far outweighed this drawback.

...that's just what I thought of these tubes in MY system. Who knows if these qualities translate to other pieces.
128x128dennis_the_menace
asa
662 posts
 
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.
dennis_the_menace's avatar
dennis_the_menace OP
467 posts
 
How about those black glass National Unions? Anyone try and compare those to the black glass KenRad VT231?
twl
3,251 posts
 
Asa, my WGT are Navy types from WW2. I expect that they would sound very similar, if not identical to the VT231 army issue. The "W" designation is also a mil-spec suffix. I am not sure what the mil-spec difference is between W and VT231. I know my WGT were Navy sonar tubes. Since you already have VT231's, I don't think it would be worth moving to the W or WGT, because I don't really know that you would be gaining anything. If it was strictly for curiosity's sake, that may be worthwhile. At any rate, I would be quite satisfied myself with a good pair of VT231's from that time period.
bwhite
807 posts
 
Dennis, I believe National Union was a company which put its name on other manufacturers tubes. If you speaking of the NU 6SN7's on Ebay now, they appear to be Tung Sol Round Plates which are good tubes.
south43
386 posts
 
Wow this a thread I can really sink my teeth into! I agree 110% with Twl. I have two pairs of the wgt's and they sing. I had a pair of the VT231's but they didn't faze me. Funny thing that version I had was not a mil spec tube. It had the same construction and from what I gathered syl made some for consumer use. What's everybody take on the grey glass rca's?
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