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Anyone recognize this valve?

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Scrit

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Thsi is a monster 27kHz valve which I need to find a replacement for. I believe that these were made by RCA in the USA, but this one has no discernable makers markings (it has a supplier name, but they want a huge amount of money for a replacement valve). Does anyone recognize it or can point me to a site which could help me identify it, please?



Scrit
 

Paul Chapman

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Scrit,

I wonder if someone like Gerald Wells could help :-k He has this museum in Dulwich - well worth a visit if you get the chance http://www.bvwtm.org.uk/

Click on "Virtual Tour", then "Page 5 valve & component store".

Has thousands of valves :shock: God knows where he gets them from.

Cheers :wink:

Paul
 

Jake

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Could try some of the big US sellers too, they call them "vacuum tubes" of course, for search purposes. "NOS vacuum tubes" will bring them up best, I think.
 

Scrit

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It's for a radio frequency glue curer and operates at 27kHz. These big valves were developed by RCA in the USA and Pye in the UK in the late 1920s/early 1930s and were apparently still in use in Russian radar sets until relatively recently

Scrit
 

bodgermatic

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I don't suppose there's a modern alternative that could be substituted? Does it just provide a 27Khz clock signal, at what voltage level? I'm guessing that two of the terminals are valve power and ground to heat the coil up, and the other two are signal (i.e.: 27KHz out) and circuit ground. Or are we going for the 'original restoration' ?
 

Scrit

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These things are supposedly still being made in China and Eastern Bloc countries. It's just that the UK manufacturer of this kit has quoted me exactly five times what I paid for MilSpec surplus RCA Victor valves for my last RF curer (a pair were £160+VAT). Sadly I've lost the documentation for that deal :twisted: As to voltage, etc. the answer is I really don't know :oops:

Scrit
 

bodgermatic

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Scrit":1tbj6z3n said:
exactly five times what I paid for MilSpec surplus RCA Victor valves for my last RF curer (a pair were £160+VAT)
Wow! Any chance there's circuit diagrams for the machine online? I've had luck in the past with diagrams for 'classic' recording studio gear - it's probably a different situation with machine tools though - I can't imagine there's a big classic machine tools circuit hacking scene...
 

Jake

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Scrit

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Well done, Jake! Thank you very, very much indeed - that was the number on the last invoice "833A". I've been quoted £450 each + VAT for these by the current manufacturer which made me swallow hard, I must say

I can now go and find a couple.

Scrit
 

Jake

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While looking I found them at $199 each at 'tube-depot' to give you a price marker.
 

Scrit

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The Russian and Chinese ones seem to be a lot cheaper, I'm just not sure how durable they are. Unlike radio or hi-fi applications, however, the sound quality is immaterial :lol: The spec. says the machine is rated at 2kW signal strength, but other than the wavelength says nothing.

Any idea how I can tell if they're working? :?

Scrit
 

Jake

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Russian valves have a pretty good reputation, not least because most of their military hardware was valve-based right up to the end of the Cold War and beyond, so they had a few more decades to perfect their manufacture, and plenty of reason to get them reliable. Chinese are Chinese - good if you get a good one. I'd go for Russian, I doubt you notice any difference over RCA or whatever.

As for testing them - erm, see if the glue sets? Or do you mean, testing whether it is the valve(s) that have gone rather than something else?
 
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