So cool to see your tube development progressing. I'm envious, but for the moment have neither the time nor space to progress down this path to any appreciable extent, but I really enjoy following along.
I'm learning to machine little bits and pieces for my various tone arms so it is interesting seeing the very fine metal working and glass forming that goes into your efforts.
I'm learning to machine little bits and pieces for my various tone arms so it is interesting seeing the very fine metal working and glass forming that goes into your efforts.
Kevin - Thank you for the comment. It's nice to know that your interested in developing the skills to make advance DIY projects. Keep in mind that there is a forum now that is dedicated to furthering the hobby of building DIY vacuum tubes at: diyvacuumtubes.com. The information is more concentrated there, but may be of interest to some of the folks that are following the tube project here.
like these "U" ´s welded to plate
Do you plan some output tubes,beefier?
811A or 812A ?
It's been awhile since there's been any activity on this thread, so I thought it would be good to give a quick update. I've had lots of interesting distractions for the last couple of months, but the DIY triode project has been slowly moving forward. The fixtures that were made for constructing the grids and plates has allowed the assembly of 10 sets of parts to be made and a form was designed to bend the filament supports. I'll be starting with a three filament parallel arrangement in the first group of tubes. Making a batch of 10 tubes at the same time will allow testing the group to see if they all have the same triode characteristics.
The aim is to be able to prepare all of the critical electrodes beforehand to assure predictable and simple assembly for the Workshop attendees. With the more difficult assembly work already done it will be much easier to weld the electrodes to the stem's feedthrough pins. The time needed to build the internal structure should be reduced from hours to down to minutes. Previous test Workshops have shown that it takes way to long for a tube to be put together successfully if the project is started from scratch. I'm still counting on being able to have a working triode built and processed in one day.
I'll post some pictures soon to show how things are moving along. Thanks to all of you who have been patiently following this thread. I'd like to also add that Trevor's forum is slowly gaining momentum. If you have time, stop in for a visit at: diyvacuumtubes.com
The aim is to be able to prepare all of the critical electrodes beforehand to assure predictable and simple assembly for the Workshop attendees. With the more difficult assembly work already done it will be much easier to weld the electrodes to the stem's feedthrough pins. The time needed to build the internal structure should be reduced from hours to down to minutes. Previous test Workshops have shown that it takes way to long for a tube to be put together successfully if the project is started from scratch. I'm still counting on being able to have a working triode built and processed in one day.
I'll post some pictures soon to show how things are moving along. Thanks to all of you who have been patiently following this thread. I'd like to also add that Trevor's forum is slowly gaining momentum. If you have time, stop in for a visit at: diyvacuumtubes.com
There are several of these old "flat triodes" that still find use by modern builders of HiFi amps. The 01A, the 30, 31, 45 and 50 and derivatives are still being used because of their linearity. Hum is not an issue if the filament is fed from a clean DC source.
I built an amp with a pair of NX-483 tubes that I pulled out of a Sparton radio chassis that I got at a flea market for $10. They are 45's with a 5 volt filament and make the nicest sounding 2 watts per channel in my collection of amps.
A few hundred watts or so of RF may be sufficient to flash the getter at its resonant frequency....may be easier said than done with the other metallic parts inside the tube...Maybe an intense, high current pulse of RF may work better for getter flashing without damaging other metallic parts like a CW RF signal may..... Just my $0.02 worth...
Reading this thread with increasing "cannot believe"!
How can anyone build a vacuum tube with characteristics comparing to one made by the professional industry.
Not to mention the life cycle quality of that home made product.
But I am astonished by the enthusiasm people are trying to produce a vacuum tube by themselves.
How can anyone build a vacuum tube with characteristics comparing to one made by the professional industry.
Not to mention the life cycle quality of that home made product.
But I am astonished by the enthusiasm people are trying to produce a vacuum tube by themselves.
RCA and the other vacuum tube manufacturers focused on quantity, not quality, especially toward the end of mass produced vacuum tubes. The EPA helped ruin domestic tube production on US soil.... Give the independents credit...they may come up with quality instead of quantity....very few tubed TV's still running these days...tubed audio is having a comeback in high end circles...
The tubes being made here are similar to what was being made in the USA in the 1920's. Manufacturing technology available to the "professional industry" in the 20's could easily be duplicated today and seriously improved by an independent producer on a small scale with a reasonable budget the NECESSARY KNOWLEDGE and access to some key surplus equipment. Stuff that was inaccessible to the average Joe just a few years ago, like diffusion pumps, roughing pumps, high vacuum chambers and plumbing can often be found on Ebay for a small fraction of what it cost new.
Setting up a small volume production line for these tubes and making a profitable business out of it is a different matter unless you have a way of building all of the specialized tooling and sourcing all the raw materials.
I don't know much about making vacuum tubes, nor would I care to venture down that path, but you have to respect someone who dared to go there, and actually DID make a working tube or two. I really DO hope that there are more to come!
After a 41 year career at Motorola designing two way radios and cell phones and setting up and maintaining radio production lines, I know a bit about producing radio equipment. The RF test and production equipment that cost US companies HUGE amounts of money has been dumped on the surplus money for next to nothing since very little radio production or design is done in the US any more.
If you are patient and good at fixing broken equipment (or making one good unit out of a few bad ones) it IS possible to build an RF engineering workstation similar to what I had at Motorola for about $2500, roughly 1% of the original prices.
The same thing has happened to high vacuum and automated assembly equipment. Some of the stuff we scrapped about 20 years ago when the manufacturing of crystals and thin film microelectronics was shut down would make cool toys today. All those huge vacuum pumps and chambers, lasers, vacuum deposition, sputtering, and plasma etching equipment could have found their way into some aspects of tube manufacturing.....there has to be lots of that stuff still out there, I have never really looked for it though.
OT posts removed.It's been a while, but I'm back on the triode path. The parts for several tubes have been sitting on the welding bench mocking me every time I passed by. Today was fateful in that I wanted to use the glass lathe to start sealing some of them up and get to building the amplifier project.
The assembly was easy since all of the parts had been previously formed and welded. The glass lathe worked really well for the sealing job and then it was off to the helium leak detector. The leak detector isn't really necessary, as other DIY'ers have demonstrated, but if you have one it can be handy at times. The tube passed with flying colors and tomorrow I'll finish the the processing and run some tests. This could be my best design yet. Well see.
1-P1040745.JPG (34.21 KiB) Viewed 25 times
The assembly was easy since all of the parts had been previously formed and welded. The glass lathe worked really well for the sealing job and then it was off to the helium leak detector. The leak detector isn't really necessary, as other DIY'ers have demonstrated, but if you have one it can be handy at times. The tube passed with flying colors and tomorrow I'll finish the the processing and run some tests. This could be my best design yet. Well see.
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