SHUGUANG TREASURES CV181 (6SN7), 300B, KT-66 - good as NOS? YES!!

As many know, over the past 15+ years, I have built a formidable collection of prime NOS tubes to feed my two amplifiers. Let's put it this way - I was into tubes in the early part of the tube revival, way ahead of the pack. And I didn't have two newborns to deal with, so I had some cash to burn through. And believe me, I burned through it acquiring tubes - and actually, at some point I started divesting of all the ones I found to be second tier, and actually probably ended up even or a bit ahead dollar wise as by the time I started culling my stash, prices had risen - a lot.

I was one of the very first, and without false modesty I can say still one of a handful of true experts on 6SN7, 6L6, 6V6, 45, 12AU7, 12AX7, 5U4 and other 5 volt rectifiers, and a bunch of others. There are maybe a dozen people in the world who can say they have had, and heard, virtually every 6SN7 produced in North America, Great Britain, Western Europe and elsewhere during the golden age of vacuum tube production. I have had dozens of pairs of metal base Sylvania's - A's and W's, and variants of both. B65's. True Holland made GT's. Ugly shit like 5692's - the best of the bad being Raytheons. Swedish 5692's. Visseaux. Neotron. Early Westinghouse GT's that nobody has ever heard. Rarities like RCA GTY's. Canadian GE GT's from 1953 that are super fine sounding. Dozens of Mullard CV181 variants. National Union, KenRad, Sylvania, RCA (I have here several pairs of the very first version RCA ever built), Tungsols (ever seen a square mouse ear Tungsol? Nope? I've got 'em.)The point of it all is - I know the 6SN7 like nobody's business, and every Russian or Chinese produced 6SN7 has been pure crap. Nowadays, you get tube dealers like Kevin Deal at Upscale extolling the virtues of some of these things trying to tag them as the new NOS, while a decade ago - while they had lots of good NOS to sell, they dismissed them.

I have been curious about the Shuguang Treasures tubes for awhile, though. For some reason, I thought - maybe now is the time to check out if things have moved along. They looked pretty nice in pictures I saw, even though I thought the CV181 designation is hucksterism at the level of selling fake Rolexes. But finally, I dipped into the right pocket seeing a well priced pair from a Chinese seller on Ebay (I figured buying as close to direct from the source is probably a good thing). I was expecting an ok sounding tube, but my expectations weren't too high - after all, I got rid of two dozen pairs of round plate Tungsols a few years back because I felt they were a bit tipped up and skittish on top, and lacked body in the presence range. Shit, I just about created the legendary Sylvania 6SN7GT 'Bad Boys' when I connected onto them with Neville in Australia. Can't be anywhere near those legends, right?

Well, not really. They may very well be just as good. In fact, they might be all around better. Crazy? No, not yet.

First - this tube has absolutely NO bass right out of the box. Like - zip. The bottle sounds nice out of the box - very nice. Right away, you know this is a contender. I has a hugely natural sound - neutral, relaxed, effortless, extended - except that bottom takes about 30 hours to fully develop. Once this tube settles in - all around, I can't say any NOS rivals it for absolute neutrality and natural musicality. It will never have the propulsive bass of a KenRad 1942/43. It's a hell of a lot tighter and more detailed bass, though. It's not the chocolaty sound of my favored 1951 National Union black glass, or the organic color of that tube. On the other hand, it has an absolutely deadly accurate tonality on everything that passes through it, and a much wider color spectrum that any NOS existing. And it throws this uncanny wide, deep stage that literally bounces off the back wall and comes hitting back at you from behind. Amazing.

Some people may find the bass lean. It isn't - it is just very tight and accurate, not at all bloated or smeared. As I switched back to a few NOS like those KenRads, or early grey glass RCA, or even the National Union, the bass was obviously fatter, but that is an inaccuracy of those tubes - they smear a lot of detail. All the bass a good amp needs is on the Shuguangs, without the cholesterol.

To get the prime forward spot in either of my amps is quite a feat and yet, since November, both have had Shuguang Treasures CV181's in place.

Throw out the preconceptions about Chinese tubes like I have had to and try these. Give them about 30 hours. This is the best 6SN7 made since the early 50's - and maybe ever.

By the way, there is a prominent online dealer trying to jack up his margins by making absolute bullshit claims about "grading" and having "premium" versions of this and other Shuguang Treasures tubes. If it makes you feel good and you have the money - and let's face it, a lot of supposed audiophiles hear better when they have spent a lot of money or have been told by someone that they can hand them a lot of extra dough and join some special club - go for it. If you just want the tubes, buy them from a Chinese seller and skip the bullshit. There are no premium or select versions. And honestly, I couldn't imagine the tube sounding any better, because the 4 pairs I have all sound perfect.

So, on I went to both the Shuguang Treasures KT-66 and 300B.

The KT-66 really does look like an original Genalex/GEC tube proportionally and construction wise. I have to be up front here - I've had many British KT-66's, from 1950's grey glass through to late production, and I thought it was a good tube, not a great one. It doesn't come anywhere near a WE350B, not actually near a 1940's Raytheon 6L6G for that matter. The Treasures KT-66 has the same out of box bass shyness the CV181 does. There isn't a modern 6L6 variant that comes close to the Shuguang, and here it's absolute neutrality and stability are the most prominent virtues. I'm still enchanted by them, and so they are still in my Komuro 300B amp. I would say that I prefer the Raytheon early 40's 6L6G, or even a Visseaux straight bottle. But those are clearly colored tubes, particularly the Visseaux. I would say that the Shuguang is the most true.

The 300B is a different story. Here there are a number of strong contemporary contenders. Right up, it tosses the overblown TJ/Full Music/Sophia/whatever punched plate totally to the side. It seems to me a better tube that the several variants of the KR I have around here. It's better than the stock EML 300B, and close but a bit back of the EML 300B-XLS, and back a bit further from the EML mesh 300B. No 300B comes close to the AVVT 300B mesh, I am keeping a few pairs of those for retirement (and if I don't make it, contact my kids about them, they'll need the money). Overall, the Shuguang Treasures 300B is the best value for money out there today. It's a very stable tube electrically, hum is low and stays low, and it has no funny arcing or other behaviors. Many won't notice any difference from superior tubes like the EMLs. It's a very fine tube and deserves to be experienced.