Last Tube

[Carl WA1KPD]

OK' OK. Strictly a QSO discussion

Suppose:

1. We are talking about tubes in use, not on display in a collectors shelf.

2. The tubes we are discussing are in common use- Not some esoteric TV or military tube.

3. Tubes are common variety, 6F6, 6N7, 12SG7. You get the idea.We are talking about a price the average person can afford for everyday use.     Arbitrarily say less then $15 each in 2007 $$


When will the last tube be gone and no longer available for use?

I say around 2050

[Tom WA3KLR]

The Mayans predicted a long time ago that vacuum tubes will cease after 2012.

[Bill, KD0HG]

Since tubes and tube audio equipment (consumer and pro audio gear, instrument amps) are still being manufactured in 2007, I'd say the question is moot.

As for transmitting toobs, they'll continue making them for a long time yet for TV and FM broadcast.

And don't forget, tubes can be rebuilt as good or better than new. It's entirely possible some entrepreneur will be putting new cathodes in 6L6s a hundred years from now.

[Todd, KA1KAQ]

I have to agree with folks who say we won't see the end of tubes in our lifetime. Sure, there will always be a few hard-to-get examples, like BBTT WD-11s, early WE 205 series 'tennis ball' tubes, and 215A peanut tubes. The thing to keep in mind is that pretty much everything electronic used tubes from the 20s-30s up through the 60s-70s, even as transistors and ICs became more affordable and commonplace. Not to mention the military, who had millions of pieces of gear with the typical backup spares. I equate the feeding frenzy for tubes like 6SN7s and so on to the big Collins S-Line frenzy a few years back. Everyone had to get some 'just because', and paid big bucks, not realizing how common the stuff was then and still is today. 

Chinese tubes were absolute trash back in the late 80s/early 90s. But over the last decade or so, they've made great strides to improve quality and reliability. Maybe we can get them to apply this process to pet food, tooth paste, children's toys and...?
Stu AB2EZ mentioned having picked up some of the Chinese 810s that work well. Having seen these myself at Dayton, and other than being a bit smaller than the originals, the quality seems good. Same goes for the 211s and 845s, although folks in the audio world still seem willing to pay huge money for NOS American manufacture examples.

I'd like to try out some of the new Russian Tung-Sol 6550s. Glad to see someone picked up the old equipment and kept things going, it's just too bad they couldn't keep it here.

As pointed out, a big enough demand will result in someone creating the supply. More likely, the AM mode and amateur radio in general are in greater peril than the vacuum tube.

[AF9J]

I'd like to try out some of the new Russian Tung-Sol 6550s. Glad to see someone picked up the old equipment and kept things going, it's just too bad they couldn't keep it here.

Hmmm, you must be referring to the Sovteks, Todd.  Mike Mathews (who owns Electroharmonix) is involved with them, and was the original instigator of getting them to make 5881s, and then 6L6s, etc.  The 6550 is popular in some audio circles, so I'm not surprised that Mike would talk them into making 6550s again.  Not only for audiophiles, but for guitar amps.  In the 1970s & early 80s (when 6550s became scarce), there were some guitar amps (Marshalls come to mind) that used  6550s.  Some guitarists hate the distortion characteristics/sound of 6550s, feeling that 6CA7s (EL34s) sound much better in full crunch mode (which is why most present day tube guitar amps do not use 6550s).  But, there are some guitarists who love the sound of 6550s.  So, there is a market for them (Electroharmonix is involved in the electric guitar market). 

73,
Ellen - AF9J

[WA1HZK]

We gotta start producing more Hams!
Go for it guys.......

[k4kyv]

Another item that is becoming extinct is the high voltage electrolytic capacitor.  A few manufacturers still produce them, but generally they are not obtainable at your local electronics parts emporium (not even considering Radio Shack, since it hardly falls in that category any more) so chances are you will have to order them.  I was able to get an exact replacement for the three-section filter cap for my 75A-4.  It was identical in size and capacitance, and the voltage rating was actually higher than the original.  I ordered it on-line, and it wasn't cheap.

I suspect the demand for this stuff will slack off a decade or two down the road, as those of us who grew up with hollow state electronics start going the way of WW2 veterans to-day. 

That will be the limiting factor for keeping these old rigs going, obtaining replacement tubes and filter caps.

[Todd, KA1KAQ]

I'm going to guess you got the electrolytic at AES, Don? Bumped up to 575 volts, IIRC. Somewhere approaching $40 or more with shipping. Fortunately the receiver only takes one, but at that price it's still not a bad investment for the future of the radio's continued operation.

When the audio deck in the KW-1 got reworked in February, AES supplied all of the caps, including the electrolytics. The cans were the new Aerovox with uprated voltages, others were Sprague Atoms and so on. My understanding from reading and talking with folks is that AES bought the old Aerovox equipment, maybe moved it to Mexico, and started cranking out Twist-Lok caps again. Quality seems very good, still too early to know about longevity.

Ellen, yes: The Tung-Sol 6550 ST 'reissues' are indeed made by Sovtek/Reflektor, bought out a while back by a US Company named New Sensor. Nice looking tubes, very close to original in appearance, at least. I've yet to get my mitts on any to play with. The CE 100V and 200V use a pair in them. I have a small stock on NOS and good used ones, but wouldn't mind getting a few more. Always wanted to build my own stereo amp using 6550s, one quad per channel. It's a cool looking tube, works well too.

[The Slab Bacon]

I aint a tube collector, but I do have a nice stash of "running spares" for all of my tube gear. I would be hyellofied at the thought of having to sideline one of my more favorite pieces of gear because a tube has crapped out. If yer gonna run this old junk you gotta have spme spare parts. At least the "expendables". that would kinda be like not having any solder, or in my house not having any coffee.

As far as the canned lytic caps go they have definately gotten kinda pricey and hard to find. Why not use axial lead tubular types, just mount em unda the chassis? I do it all of the time. Most of the more common values are still available from Mouser, Digi-Key, and some of the other suppliers at fairly reasonable prices. A cap is a cap, the electronz dont care what it lookz like.

6550s make killer AB1 modder tubes for Rangers and other lower powered transmitters. They run great in AB1 so they dont need to be driven into grid current. No grid current meanz you can feed them from a fuzz inverter. You dont need a strapping driva, just tickle the grids with a little voltage and watch the munky swing!! Wrap a little feedback around them to clean up the audio and they kick butt and take names! With a little adjustment to the bias voltage, you can just about stick them anywhere you would a 6L6.

                                              The Slab Bacon

[kf4qkr]

 I guess when all the tubes run out mabee  we can rebuild old ones or get up with a glass blower and make our own tubes . Didnt they do that back in the early days of radio ?

[W1GFH]

I predict that the last tube will be a 12AX7 (current estimated annual worldwide sales of greater than 2 million units) preserved in a museum display at an Earth colony on Alpha Centauri. Children will point to it and ask why a primitive group of iconoclasts worshipped such inefficient devices.

[WBear2GCR]

Perhaps tubes will not last as long as you might think?

That's because the suppliers of some key parts may not be able to stay in business!
Once the CRT is fully dead (like sometime within the next 5 years??), the economic basis for the production en masse of things like certain metal alloys, ceramic shapes, chemicals will be sharply reduced. That will drive the costs of the raw materials WAY up and quickly!

Now one of the key elements, tungsten wire, will also fade out as there is this big push off standard lightbulbs to the compact fluorescent. (entirely unclear to me that it takes less energy to make them than it takes to run the other, but whatever) Once plants cease to produce billions of ordinary lightbulbs the factory that refines and those that draw the wire will vanish. The cost of tungsten wire will go WAY up.

Don't they use nichrome wire for indirect cathodes? Not sure if that supply will change, but I suspect that the demand in 2000 for nichrome for CRT guns was 1000x or 10000x that of the demand for nichrome for vacuum tubes. When the demand for the wire for CRTs vanishes, the factory that draws that wire will vanish.

Unless of course there is a demand for the same or similar materials for other applications/industries, these speciality factories (which are relatively small in terms of  industrial scale) will go bye-bye.

Who will pick up the slack? Or IF the Ruskies or Chinese tube factories see this advent perhaps they will have bought up the supplier's companies, which will make ALL the difference as to the extended practical "life" for tube manufacturing at somewhat reasonable prices and quantities.

At least that's how I see the future.
Anyone wanna go in and buy up a Mica mine?   

                _-_-WBear2GCR

PS. New Sensor is ElectroHarmonix

PPS. that new factory won't be in China in 2050, it will be in Africa...