I’d be interested! I’m an audio engineer (FOH and A2 sound guy) and system designer/integrator by trade. Would love to learn more about the tube amps I use a lot as well as maybe build a small, tube amp. Maybe a headphone amp?
30 year restorer of tube radios here. ~20 years TV, 25 years jukeboxes. EE degree but all the tube stuff is self-taught with the help of a few retired TV/radio repair guys. I’d be game for helping teach a course or two. I’d approached VECTOR about doing it a few months ago but life had other ideas. PM me.
Mike
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Matt A, noted. Would be cool to get a FOH guy’s perspective in the class. You guys deal with all kinds of challenging, real world problems. Glad you’re interested.
Mike, that’s great to hear! I think collaborating on course content and co-teaching would make for a much better class. I’ve got quite a busy schedule for the next few weeks, but I could meet up at DMS one day for a couple of hours to talk about class content and maybe divvy up some pre-work (projects to bring/demonstrate, slides, etc). Thanks for offering.
I’ll PM you if the above sounds good and we can find a time. If you have better ideas, I’m all ears, too.
Josh, that’s what I use for the custom studio gear I build. One offs only (not a boutique operation), but the logo has a brontosaurus silhouette with “Jurassic Pro Audio” beneath it.
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Rich,
Spot on, Rich. While not a testing instrument in the vein of traditional gm/dynamic transconductance/emissions testers, I mentioned the U-tracer as I think there are likely a fair number of folks whose main interest might lie in tube instrument amplifiers or hi-fi, where tube matching for PP output stages, balanced input stages, or compressor/limiter circuits would be a common need. While there are cheaper methods of matching tubes, I think it’d be worthwhile to spend a few minutes on options like the U-tracer, among others. I’m sure you know the Tektronics 576 and its ilk performed a similar function, but powered the tube and injected a signal using traditional methods. Those have made a nice comeback with many old units restored to former glory as awareness has grown of them. I think spending some time talking about those would also be worthwhile.
But as you say, not really testers in the sense of good/bad, weak/strong testing.
These great instruments are still around. Many of them have a bad or weak CRT. The CRT is the hardest repair part to find.
For a lot of FOH applications, the newest emulators on the market (slate, etc), actually do a pretty great job! In a live environment, it can be incredibly difficult to tell the difference between a tube amp (most of which aren’t mic’d correctly anyway) and a good (expensive) emulator, at least in rock shows. In the studio, however, tubes make massive sonic differences. You may not hear the difference on its own, but you’ll gain clarity in your mix that can be hard to obtain otherwise.
Excited to see what you guys come up with!
Any new thoughts on the tube topic? Plans for a class? I have a Tandberg reel to reel sitting in my garage I would love to get working again. Class would need to have some piece on high voltage power supplies. Most times the power supplies seem to die while the tubes are fine.
Glad to hear there’s more interest! I’ve been working on and off for the last couple of weeks on this - drafting an agenda, building/digging up/stealing power point slides, digging out example components/projects/teaching aides, etc.
Before I submit the class and proposed dates, I’d like to post the final draft of the agenda here to get everyone’s feedback.
It’s pretty clear at this point that to do this right, we’ll have to make it at least a two part class. Hate to do that, because it’s harder for people to get the time to attend multiple classes just to get through a particular subject, but I don’t think people will want to sit through 5 or so hours of class in one sitting. I may be wrong, but that’s my impression at present. Would like folks’ feedback on that.
And you’re absolutely right about needing a section or two on power supplies. Other than faulty/dried out caps (I’ll include PS filter caps here), power supply issues are the number one root cause of problems with tube gear (I could say the same about vintage solid state gear as well). I already have a lot of the material on that topic pulled together, in fact.
At present, I’m thinking a mid-September date/dates are what we’ll have to shoot for.
Any thoughts on this are welcomed.
Thanks,
BT
Still interested in the class. I think I may have an old tube textbook in my garage, if it would help.
Found 2 books, one on electron tubes specifically, one being a undergrad EE text book from 1940s (everything was tubes back then). I am at DMS this Thurs, evening, Fri evening, Sun late afternoon, if you want to borrow them
Hey Neal. Very kind of you. I’d definitely be interested in looking through them. Do you know the titles offhand? I’ve got quite a lot of ancient electronics manuscripts (written on papyrus, of course ;)) from the tube era. If you’ve got one or two I don’t have, then I’d love to make a trip over to DMS to check them out. Always interested in those old textbooks.
And if anyone else is interested, I have a huge collection in electronic form. Several of which I scanned myself, so you may not have run across them on the web before. Happy to share them out on my Google Drive.
When Electronics moved to the New World™, there were some old books covering vacuum tubes. @artg_dms
Think most of those belong to Jason @engpin .
Try searching archive.org and bitsavers.org for starters
Old txt books and databks in pdf format.
I would definitely be interested in learning about tube amps. I’ve made a few amps based on designs I found here http://www.runoffgroove.com/articles.html and would definitely be interested in learning more or stuff about pedals.
I was in need of some tube bias probes the other day when I was working on my 6505. I bought it used and I have a feeling the previous owner tinkered with the tubes since the back cover is missing.
I’m no expert in the field but would be very interested in learning more both as an electronics technician and a musician. I know how tubes amps work in theory, but lack the practical knowledge to work on them. I would love to become more well versed in the subject matter.