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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
kana813
956 posts
 
D_t_m- have you ever tried any mil spec 5692 in place of
the 6SN7s?
dennis_the_menace's avatar
dennis_the_menace OP
467 posts
 
No, haven't tried any 5692... but I'd be curious to hear your opinions on them. Have an opportunity to get some National Union black glass... think I may wait until I get the preamp that needs a 6SN7 before I invest anymore in 6SN7s. The kenrads are really awesome...
gunbei
2,327 posts
 
Asa, the characteristics you're describing seem very much like the differences I hear between Sylvania VT-231s and the clear glass Ken-Rad VT-231s I'm currently comparing. Are you saying that the black glass Ken-Rads have even more of what you're decribing over the clear glass? After trying the Ken-Rads for a week, it's a little tough listening to the Sylvanias, they seem more detailed, but also quite thin in comparison.
kana813
956 posts
 
D_t_m- the 5692 & 5691 are more neutral sounding and usually
have a lower noise floor and are less prone to vibration.

If you get a chance check out the RCA brown base.
bwhite
807 posts
 
The Clear Glass KenRad VT-231's and 6SN7GT's are not even close to the Black Glass versions. It's a night and day difference. Compared to the Black Glass, the clear is 2 dimensional, thin and quite unnatural sounding. If you've been listening to the clear glass, you're in for a real treat when you try the Black.

Also noteworthy, the Black Glass VT-231 is different than the standard 6SN7GT. While I think the VT-231's are a bit better overall, the lower through upper midrange of the standard 6SN7GT's is stunningly accurate. The timbre is as perfect as I've heard from any tube. Unfortunately, it does tend to roll off the highs more and you loose a sense of air. The mids of the VT-231 is a wee-bit more shallow - (less weight and body & a bit less organic) - in the mids by comparison. But the VT-231's highs are more extended so you will not loose the sense of air. As in everything there are trade-offs.

As far as I am concerned, the Ken Rad Black Glass is easily the finest 6SN7 tube available.
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