I've read that thread. Sounds like you were having trouble with some KT66 TungSols and I think we now both know why.
Am I to assume that iggs is the Igor Doc referred to ? :-)
So I guess the bigger question becomes: Is the only thing that makes the T-S KT66 "not real" the Pin 1 connection to the metal band? In the words of one of my buds, "Does it have the skinny cathode of a 6L6 or the correct wider cathode of a real KT66?"
When I read Doc's statement, I thought his source for calling it a faux KT66 was possibly someone in tube manufacturing who knew the "particulars". [certainly not intending to downplay iggs' tube knowledge by that statement either] Granted, it's enough that it has the bogus extra connection - but there could be OTHER applications where it might be a perfectly good KT66, IF it's internal construction is otherwise OK. That was my question. DEFINITELY no good in the Rt. 66. [Questionable in my mind at this point for other apps.]
I guess the reason I "obsess" a bit is because the New Sensor / Sovtek folks have "repackaged" some old internals in new bottles and given them a new number in the past. I'm just trying to nail down what I'm getting, and I doubt I'll get a straight answer from the manufacturer. They don't even have data sheets for any of their tubes. It's only through the efforts of folks like Myles and others like him that we really get to know.
Myles, Have you dissected one of these bad boys yet?
[ can't believe on the first pass the filter changed "one of my a*ssociates" to "one of my I disagreeociates" - sheesh ]
Not sure about the particulars of the T-S innards but I've read posts on other forums that folks have been using the T-S KT66 and they seem to like them, however, this tube will only work in an amp that does not use pin 1 as a tie point for anything. So it's not just a Route 66 issue but rather an issue for any amp that uses pin 1 as a tie point and will potentialy short via the metal tube base.
The way I see it, if T-S wanted to make a new KT66 they should have respected all KT66 build and tech specs because if the "old" KT66 did not have pin 1 used for anything then one should assume that an amp builder will take that into consideration when designing their circuit. If T-S wanted to issue a KT66 "with a twist" they should have either marked it different or somehow made it known that their KT66 deviates from the original spec and design.
From a consumer standpoint, if I buy something labeled KT66, I want to get a KT66 and not have a "sort-of" KT66 that will fry as soon as I take the amp off standby. Luckily the amp did not get damaged, but what if it did?
I absolutely agree, iggs. For all we know, there could also be an element *inside* the tube connected to Pin 1. I'll be placing a call to the New Sensor / "TungSol" folks today. Not really expecting to find out anything, but it's worth a shot. They need to get their ducks in a row. :-)
Doug's Tubes still has some of the KT-66 Saratov [same as GT KT66-HP] in stock according to their website and I've ordered one for the amp I need to retube..
Nice talking with you, and glad your amp came out of the deal unscathed.
Just had an interesting conversation with J.C. Morrison, who is the person responsible for the design of the TungSol KT-66.
He was (immediately) very defensive of the product, and informed me the only reason it even exists is that they were able to utilize the tooling of the KT88, which they also manufacture. [guess what - they also have a metal base band connected to pin 1] He went on to further tell me how pin 1 was connected to the cathode "just as it is in all 7AC based tubes" and "the cathode is at ground potential in about 99% of all guitar amplifiers because most are fixed bias". He couldn't see how the metal band being connected to pin 1 could cause too many problems, and even challenged me by asking if anyone even made a guitar amplifier that used KT66 tubes. I won't even mention what he thinks of guitar amp manufacturers and those who own tube guitar amps. He's a Hi-Fi guy, you see...
Well, I'll have to assume he got confused with all that looking at both sides of a tube base, because it's pin 8, the other end of the pin circle, that's the cathode on basing diagram 7AC. [unfortunately, I wasn't looking at a tube manual when we were talking, or I would have questioned him]. It will be easy enough to verify with an ohmmeter if there is continuity between pins 1 and 8 - but I doubt it.
I asked him if the plate structure was that of a KT88 as well and he said yes it was [although the Electro-Harmonix and Sovtek KT88 plate looks different to me than the T-S KT66]. He said the plate is "triple thickness" (called tri-alloy in the Sovtek KT88 literature and the grid (I'm not sure which one) is wound from 100 uMeter wire instead of the thinner wire used, I assume, in the previous russian KT66 [so many questions, so little time]. So it sounds like the thing's built like a tank. It also appears to be exactly what Doc observed - KT88 guts in a 6550 bottle.
J.C. Morrison's advice to me if I couldn't use the T-S KT66 in my application was to use the Chinese version. "With it's reduced lifespan?", I asked. "Yeah, and they sound like crap." he added.
I know that is probably "too much information" for y'all, but I started it and had to give a shot at finishing it.
I think we all are aware that there aren't any 'real' Tung-Sols or Mullards being manufactured anymore. These trademarks were acquired by New Sensor and they have directed their factory to manufacture some reasonably similar lookalikes complete with replica old-school graphics and packaging. To think they are a close recreation of those legendary tubes, with all their unique metallurgy, chemical recipes and production techniques is a bit of a stretch. New Sensor is doing what they can with what they've got, which -I believe- is the Expo-Pul manufacturing facility in Russia. To be fair, anybody who can successfully run a going concern in the political and business climate in Russia deserves a lot of respect, but that doesn't translate directly into recreating the magic of defunct companies and their unique secrets and techniques. Mike Matthews' team may know very well what the magic elements of those tubes are, but it's entirely possible that there is no possible way to get that combination out of their existing manufacturing capability. I, for one, have no serious interest in their Mullard, Tung-Sol or Svetlana 'copy' brands. They're interesting for what they are - another flavor variation from New Sensor, but they are in no way a match for the names they are using. If I want a tough as nails power tube, I'll go to Winged C and get the Svetlana I have always known. FWIW, I seem to keep coming back to JJ for almost everything except KT66 and I look to GT, TAD, and Shuguang in general from any decent reseller, for those.
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