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tube fanatic

Why some tubes are expensive!

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Wow! I had no idea how much hands-on work was required to produce a tube.

Very cool video, thanks for sharing.

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B) If only everything was made by craftsmen with so much attention for detail .....

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The things we take for granted. Yes, thanks for sharing!

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I wonder what the secret coatings were.

JJKI

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Very educative, fun to watch. Thanks for sharing this video showing a craftsman at work. B)

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Glad you guys are enjoying the video. Contrast the above with these 1942 RCA promotional videos showing how tubes were manufactured in a high-yield factory setting. When you consider just how many tubes were turned out their reliability is even more remarkable.

http://www.youtube.com/watch?v=QCksgN7kiv4

http://www.youtube.com/watch?v=J61hHMjxzC4

I love tubes!!!

Maynard

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Just think now they can make nano-tubes and fit them into a CPU a billion at a time.

JJK

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Great video Maynard!

Another thing besides the intense labor involved most should realize from this video is the fact that being largely hand made is the reason they often fail. They always did regardless of the era they were made. Tubes are wonderful devices but they were not sold on every corner back in the day because they lasted forever! The finicky nature of the tubes themselves is what opened the door for SS gear! Many of us are willing to forfeit a little time and patience for the added sonic joy of tubes but the general public at the time was completely sick of buying and messing with tubes. They surely didn't swap in the early SS gear for its sonic superiority. Realize that tubes were in almost every electronic device back then!

One of my favorite sayings when problems arise with good electrical condition tube gear is.... "the problem with tube gear is the tubes"

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In addition to the points made by Craig about tube failure, another common cause was excessive heat. Most radios and televisions had inadequately ventilated cabinets (probably intentional on the part of the manufacturers) which, combined with owners placing the units nearly flush with the wall behind, caused the tubes to run at much higher temperatures than they should have. One need only look at the cabinets of many radios of the tube era to see distinct burn marks directly above the rectifier and audio output tubes. Under the chassis, temperatures were often so high that the wax coating on the typical paper capacitors used back then literally melted off leaving blobs of wax on the bottom of the cabinet. When amplifier manufacturers got away from the open chassis designs (typical in the 50s) in favor of enclosed cabinets, similar issues often surfaced. The enclosures didn't provide enough ventilation for the output tubes, and owners often placed the equipment inside poorly ventilated cabinetry. Some manufacturers also pushed the operating points of the output tubes on the high side of the design-center values which caused the tubes to run even hotter. Not a good scenario for longevity, but remember that they were relatively cheap and abundant back in the day, and the manufacturers certainly wanted the consumers to purchase lots of them!

Maynard

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Seen this one B4 .... Taken into consideration the time and naturally expense of building valves it blows your mind when the military sells off their surplus for pennies on the dollar !

A few years back i won a military auction for over 4500 valves .... If i told you what i paid for it you would cry ! ( under a thousand )

200 - 300 sleaves of mid sixties 6SN7 GT , KT-88's out the zing zang as well as 2A3 .... 300B's from the 50's and 60's

I had over 200 5AR4 rectifiers from the mid 50's still in the original packages ...lol

Funny thing is i sent Craig an E-mail asking if he was intrested in the lot and i would purchase them for him cuz i live in western Canada ... Never returned my E-mail so i bought them myslft and have made over 20k selling them slowly on e-bay and Kijiji ...

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Well good for you...I do not recall ever getting an email about it.

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I love watching "How it's made". This was another great episode, thanks for posting.

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