Anyone a Vacuum Tube Electronics Fan? - Page 1
Forum section: electronics / general

author: 6E5
author_rank: Regular Contributor
timestamp: February 19, 2014, 02:18:31 am
content: Hi,For quite some time know I've devoted significant resources and time to restoring old vacuum tube equipment, such as radios, tvs, and test equipment. One of my pride and joys is a Tektronix 575, which is a 100mHz oscilloscope with over 100 vacuum tubes.Anyone have any interest in old hollow state electronics?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 19, 2014, 02:28:53 am
content: SexyfiveTubes are fair game in my book. Not so easy to use, nor interesting in specs (except for the oddball ones), but still handy to know.Tim

author: free_electron
author_rank: Super Contributor
timestamp: February 19, 2014, 02:30:36 am
content: i like the sound of vacuum tubes when they are being hit by large hammers.( ducks for the impending flame war )

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 19, 2014, 02:40:16 am
content: Quote from: free_electron on February 19, 2014, 02:30:36 amA fan of theavant gardeschool of amplifier design I see

author: free_electron
author_rank: Super Contributor
timestamp: February 19, 2014, 02:46:03 am
content: all that newfangled technology using vacuum tubes or solid state..real men make circuits with relays !

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 19, 2014, 02:49:40 am
content: Reminds me, some day I should build a subwoofer amplifier with thyratrons.Even a simple inverter using tiny 2D21s should be capable of a hundred watts or so!Tim

author: N2IXK
author_rank: Frequent Contributor
timestamp: February 19, 2014, 03:00:43 am
content: Yeah, there are a few of us tube freaks around here....Never mind "Free Electron". For a guy so identified with the history of "Silicon Valley", he seems to forget about the tube companies that really founded the electronics industry out there. Companies like Varian, Eitel-McCullough, Heintz and Kaufman, Federal Telegraph & Radio, and Litton Industries were making "GlassFets" in the area long before the advent of the semiconductor industry.

author: 6E5
author_rank: Regular Contributor
timestamp: February 19, 2014, 03:49:10 am
content: Quote from: T3sl4co1l on February 19, 2014, 02:49:40 amT3sl4co1l-Sorry to be so anal but if you're talking about this tube:http://www.radiomuseum.org/tubes/tube_2d21.htmlI'm puzzled as to how that would work. Thyratrons are basically antique SCRs, they are triggered by a pulse, and won't turn off until the plate voltage gets down to 0. Correct me if I'm wrong, to be honest I haven't played around with Thryatrons too much.Now a real amp would be a giant Class AB push pull with 833a tubes! That would knock down the front door. Even my small 15 watt push pull stereo amp with quad 6V6 tubes can annoy the neighbors.Now I'd like to disagree. Tubes are very easy to use and forgiving. You try running a set of IRF460's at twice their rating voltage!N2IXK- Yes, the history of tubes is quite fascinating. Some good book include Empire of Air, Saga of the Vacuum tube, Radio Manufacturer's of the 1920's (all 3 volumes), and Tube Testers and other Classic Electronic Gear.Here's a great website for newbies to tubes.http://www.angelfire.com/electronic/funwithtubes/Here's my Holy Grail Radio, the Zenith 1000Z Stratosphere.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 19, 2014, 04:10:20 am
content: Quote from: 6E5 on February 19, 2014, 03:49:10 amMmh, turn off when plate voltage falls below 10 or 20V I think, or more to the point, if current flow drops below holding current, AND enough time passes for the ions to recombine. (Grossly the same physics as in a thyristor!) If you skip that last key step, it'll keep right on conducting when the voltage comes back.Inverters are easy to make, you just have to provide some means for commutation (turning one off and the other on). Usually, while one side is on, the opposite side is triggered, shorting out the supply, which swings around by means of a resonant tank circuit, reversing current long enough for the opposite device to turn off. I've played withthis examplebefore: the minimum pulse width was something like a hundred microseconds for the devices I used, so you get useful PWM range up to a few KHz (i.e., a duty cycle of, say, 30-70%). There are equivalents for PP, full bridge, and supplementary commutation (i.e., an outboard device which can trigger the mechanism, resulting in all devices turning off).Tim

author: 6E5
author_rank: Regular Contributor
timestamp: February 19, 2014, 04:16:54 am
content: Hey Tim,Ahhh, why didn't I think of that! I was thinking of a classic Classic A,B, or AB amp and I said to myself, "How does he expect that to work?"Anyway, thanks for that info. I haven't done much design, I'm more of a repairman than anything else.

author: Psi
author_rank: Super Contributor
timestamp: February 19, 2014, 06:28:02 am
content: Big tubes are good for tesla coils and other high voltage projects.Sure, you can switching 4kV with expensive mosfets/IGBT but any spikes or other problems and $100 worth of semiconductors will fry in a micro second.Or you can use tubes that will happily switch 5-10kV at high power levels and are almost impossible to blow up.

author: G7PSK
author_rank: Super Contributor
timestamp: February 19, 2014, 09:25:31 am
content: I also like valves/tubes, I spent many happy hours as a kid standing them on walls in neat rows and then knocking them off wit an air rifle and TV cro's were even more satisfactory in combination with a .410 or 12 bore.

author: N2IXK
author_rank: Frequent Contributor
timestamp: February 19, 2014, 02:23:40 pm
content: Quote from: 6E5 on February 19, 2014, 03:49:10 amAll good ones for sure. I would also recommend "70 Years of Radio Tubes and Valves" by John W. Stokes, "75 Years of Western Electric Tube Manufacturing", by Bernie Magers, and "Tube Lore" by Ludwell Sibley.Anyone with an interest in the history of these devices should consider a membership in the Tube Collectors Association. The TCA publishes a bimonthly magazine "Tube Collector", with all kinds of fascinating info and history, and they also offer a DVD "Data Cache" containing registration info and .pdf datasheets for essentially every EIA registered tube type.http://www.tubecollectors.orgKeep 'em Glowing!

author: 7vl3aq@gmail.com
author_rank: Newbie
timestamp: January 07, 2015, 05:36:29 pm
content: I know this thread hasn't been posted in for a while. It's a little bit to perfect for my needs to start another thread, though.I'm really looking for two things. One is a forum for vacuum tube users. Another a thread for hybrid users. (Replace some tubes in a piece of tube equipment with semiconductor devices.)Does anyone have any suggestions where I might look? I'm an experimenter. I don't really build things that have any use.

author: JDubU
author_rank: Frequent Contributor
timestamp: January 07, 2015, 06:18:07 pm
content: Quote from: 7vl3aq@gmail.com on January 07, 2015, 05:36:29 pmTube audio:http://www.audiokarma.org/forums/forumdisplay.php?f=14http://www.audiokarma.org/forums/forumdisplay.php?f=54

author: Artlav
author_rank: Frequent Contributor
timestamp: January 07, 2015, 08:55:53 pm
content: I like big power valves, and using them when they are superior.The closest thing to tube audio was a directly modulated plasma speaker.A valve can swicth tens of KV on it's own, making a charmingly straightforward circuit, compared to the typical PWM-it scheme.Some of them are just cool, like this 1.5 megawatt pulse modulator. 33KV at 40A.You can really see the blue plasma glow in something that big.No practical applications at hobby level, however.Full gallery there (in russian, but the pictures speak for themselves):http://lavart.livejournal.com/3340.htmlRegular tubes...Well, i tried blinking a neon tube with a valve and a 555 timer...It's kind of... Meh?

author: Excavatoree
author_rank: Frequent Contributor
timestamp: January 07, 2015, 09:53:41 pm
content: Quote from: 6E5 on February 19, 2014, 02:18:31 amIs "575" a typo? A Tek 575 is a curve tracer. (I've got two of the things, but there are other forum members that have very nice examples)I think I have an old 535 that sort of works, and a 545 that almost works, but probably has a few problems. I did have several tube scopes, but I realized that they were very far gone and I just didn't have the motivation to fix them. I've got some parts left, and some scopes that are, in actuality, parts units.I've got a few tubes/valves as well, I can't bear to throw them away.

author: vk6zgo
author_rank: Super Contributor
timestamp: January 08, 2015, 04:20:32 am
content: Quote from: Artlav on January 07, 2015, 08:55:53 pmIf you want to blink a neon,you don't need a 555ora tube.Just use the HT supply you need for the tube,along with a CR network.If you absolutelyhaveto use an active device,use a 12AT7 or similar twin triode as an astable multivibrator.

author: electrophiliate
author_rank: Regular Contributor
timestamp: January 08, 2015, 04:44:05 am
content: Quote from: free_electron on February 19, 2014, 02:30:36 amReminds me of a scene from The Philadelphia Experiment (1984):

author: vk6zgo
author_rank: Super Contributor
timestamp: January 08, 2015, 09:46:47 am
content: But wait!----There's more!http://en.wikipedia.org/wiki/Pearson%E2%80%93Anson_effectThis gives a circuit & theory for a Neon Relaxation Oscillator.No 555,no tube,just a resistor,capacitor & a Neon.

author: dave_k
author_rank: Frequent Contributor
timestamp: January 08, 2015, 10:02:53 am
content: did someone say tube amp?

author: Artlav
author_rank: Frequent Contributor
timestamp: January 08, 2015, 08:04:58 pm
content: Quote from: vk6zgo on January 08, 2015, 04:20:32 amSure, but the essence of the art here is in taking three generations of devices and combining them into one thing.I'd thrown an FPGA into the mix, just for the "crazy" credits, but that would require etching a PCB.