Part 15 Tube Transmitter!

I know this transmitter from a guy who had one, it looked the same but used a glass crowned tube and you could see the filament glow orange. There's a zap point between the woven tuning coil and another part and I got a shock when sliding it across the table top. Not a bad zap, but a surprise, and if you were holding it might drop.

There's a way to add a quartz crystal to lock down the frequencty. Interesting what it costs, in dollars that would be ten times what a kit like that would have cost in the 1950s or 60s, going by old ads. Junior Radiomen would probably just go to the electronics store and buy the parts for a few dollars, and cut the wood base themselves.

That is a 12SA7 metal tube, and the RCA Tube Manual says the 12BE6 glass tube is similar in performance, so that would be a way of getting that magical glow that really makes a tube come alive.

my understanding is tubes are no longer being manufactured, not even in russia anymore and what is left NOS is all there is and as that supply dries up and tubes become harder to obtain they become more expensive adding signifigantly to the cost of the kit.

industry switched totally to solid state about a decade or more ago.

the hobbyist market both RF and audio just isn't enough by itself to sustain a tube manufacturing plant.

i think russian manufacturers were the last hold outs and then they finally quit.

I just purchased five NOS tubes for a project where I need two so I now have three spares. They were $3 each and were easy to find. A great many tubes are available at reasonable cost. One reason is that market demand is falling faster than the stock being held for sale.

True, there is demand for premium audio tubes (KT-88, 6L6, etc) and they command high prices but the common tubes are available for an OK price.

If tubes are operated within their specs then the life is very long. In my years of electronic activity I have replaced more blown solid state devices percentage wise than I have replaced blown tubes.

Neil

MCM Electronics lists a lot of tubes because musicians love the tube amplifiers which are in good supply and very popular.

Here's a good read about tubes from Wikipedia:

https://en.wikipedia.org/wiki/Vacuum_tube

BREAKING TUBES, uh that's not right... BREAKING NEWS:

Will 12 million tubes be enough?

http://www.vacuumtubes.net/?source=google&gclid=CL76i6qH9ccCFQ4paQodFRYBkw

The majority of guitar amps(better ones) and a lot of hi-fi stuff is tubes so they have to be available and the companies have to have someone who is making them.

Carl, I like tubes too.....the Marconi radio I grew up listening to looked good with the 6 tubes all glowing when you looked at the back.

Mark

There's a heck of a lot of new stuff being sold that has tubes in it.  Someone's gotte be making plenty of them.

Look at any musician catalog.  American Musical Supply, Musicians Friend, any of those big outfits.  My Son is a guitar player -- he's been fronting a band of some sort since he was in grade school -- and he uses tube amps, in fact just last week bought a brand new Marshall amp with tubes in it. All the big companies, Fender, Gibson, Marshall, Vox etc are making and selling new amps with tubes in them.  He has no trouble buying new tubes for his gear.

Ameritron is still selling brand new ham radio linear amplifiers with tubes in them.

Check the Acoustic Sounds website.  High end audiophile stuff.  Plenty of brand new amps, pre-amps, phono amps, headphone amps, all chock full of brand new tubes. 

I've used exclusively tube ham radio gear for decades -- up until I have in and bought a new fancy pants digital solidstate Icom transceiver a few months ago.  I've a basement full of Swans, Colling, Johnsons, etc all full of tubes and I've never had a problem finding replacements to keep 'em all going.  The interwebs are full of tube sellers.  I have several thousand NOS tubes in the basement and about four 5 gallon pails full of good used ones.  I'm amused by the "modern" ham radio guys who always talk about how horrible it will be when I have to replace an expensive poweroutput tube and it costs like $50 or $100 bucks. Then I ask them "When a power output circuit fries in your fancy pants radio, how much is it going to cost you to replace them" then they realize that they sure can't fix them themselves and they'll be sending them in to get fixed -- a new tube is a lot cheaper. 

I have no trouble finding tubes for the 60's era Collins back backup transmitter at the station I work for. Nor for our Harris MW-5 from the 70's, or the vintage RCA mid 70's FM transmitter for our other station. And these are huge, very low volume specialty tubes. 

I'm pretty sure the suppy of tubes will last far longer than I will. 

OH, and yes, my transmitter like the one above has a glass tube. I imagine they vary what goes out with the kits based on what tubes they have the most of 🙂

TIB

That would be different than the real 1950s transmitters, they would have needed a selenium stack or diode tube, and some used a 120 volt filament tube.

As for power output that Tib mentioned, I wonder how you would even measure it, there are no meters on the thing. I think the guy's had a neon bulb on it to tell when there was power on, but not for RF tuning. It's been too long and I don't remembe what the range was.

I read that some of the bigger phono oscillators could put out a couple of watts, a claim that was read on a page about the Knight unit, but it didn't mention what tests were done.

Neil Said: "If tubes are operated within their specs then the life is very long. In my years of electronic activity I have replaced more blown solid state devices percentage wise than I have replaced blown tubes."

I said: This is very true.