neon tube circuits

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andrewF
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neon tube circuits

Post by andrewF »

RSFC & I have both played around with using neon bulb based circuits in synths. They are cheap simple and relatively low voltage - 100V is plenty.
Time to get a resource thread of schematics and info happening.
I will dig a few out today.

The Glow Lamp Manual is here - http://www.electricstuff.co.uk/oldbooks.html
Here's a pic to get things started
neon LPG anyone?
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decaying.sine
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Post by decaying.sine »

Interesting. The VTL3B18 turn on time is much (e.g., more than 2x in some cases) longer than the VTL5Cx vactrols.
Brian
"I must create a system or be enslaved by another mans; I will not reason and compare: my business is to create." William Blake

"Vactrols ringing, Dude." "Thank you Donny"
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andrewF
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Post by andrewF »

neon organ - http://guitarfool.com/NeonOrgan.html

references -
1. ^ J.W. Tuttle and C.R. Dougherty, ed.s, General Electric Glow Lamp Manual (East Cleveland, Ohio: General Electric Co., 1963). See especially the section "Logic and Computer Applications of Glow Lamps," which presents circuits using neon lamps in "and" gates, "or" gates, inverters, pulse generators, flip-flops, and ring counters.
2. ^ William G. Miller, Using and Understanding Miniature Neon Lamps (Indianapolis, Indiana: Howard W. Sams, 1969).
3. ^ A.A. Vuylsteke, "Neon lamp flip-flop and binary counter," Electronics, vol. 26, page 248 (April 1953).
4. ^ M.S. Raphael and A.S. Robinson, "Digital storage using neon tubes," Electronics, vol. 29, pages 162-165 (July 1956).
5. ^ Charles E. Hendrix, "A study of the neon bulb as a nonlinear circuit element," Proceedings of the Institute of Radio Engineers: Transactions on component parts, vol. 3, no. 2, pages 44-54 (September 1956). (Use of neon lamps in "and" and "or" gates.)
6. ^ J.C. Manley and E.F. Buckley, "Neon diode ring counter," Electronics, vol. 23, pages 84-87 (January 1950).
7. ^ R.L. Ives, "Neon oscillator rings," Electronics, vol. 31, pages 108-115 (10 October 1958).
8. ^ C.E. Hendrix and R.B. Purcell, "Neon lamp logic gates play tic-tac-toe," Electronics, vol. 31, pages 68-69 (20 June 1958).
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andrewF
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Post by andrewF »

decaying.sine wrote:Interesting. The VTL3B18 turn on time is much (e.g., more than 2x in some cases) longer than the VTL5Cx vactrols.
I dismantled some old lab gear that had a rack of neons mounted with pairs of LDRs. They weren't vactrols but mounted in little metal enclosures, I used them in two of Rene's tube VCFs


another interesting page - http://www.instructables.com/id/Steampu ... c-Machine/
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metasonix
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Post by metasonix »

I should warn you, having tried them--neon-LDR vactrols do not behave with anything resembling useful linearity. They are strictly on-off, and the negative resistance region of their V-I curve makes even that use "interesting".
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sduck
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Post by sduck »

As someone who studied neon sign engineering at one point with an eye to a career change, this thread is relevant to my interests.
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Post by Rod Serling Fan Club »

I came across this circuit that could probably be modded into a sort of baby12 style sequencer:
Image

http://www.circuit-finder.com/categorie ... ne-2-ne-51

There are a variety of oscillators you can make with neons and they have unique shapes like a shark-fin saw/tri (gets more tri/sin at higher pitch and more saw at lower), a houndstooth looking wave, etc. Many examples in the GE books. I have made 2 of these on breadboard that work great, sound good. Since neons don't act in a very linear fashion the best way to make them more tonal is to sync them to a stable oscillator. This is what was done with the old divide-down neon organs such as the one posted by Andrew above. Back then it was done with a more stable tube but one could drive them with any modern oscillator or use them in an unlinear fashion.

It may be obvious one could make a sub oscillator using the divide down circuits as well. There are a few examples of the divide down organ circuits floating around.

So far I have been using resistors to divide voltage but I'd like to explore audio transformers. If anyone has good info/advice on those I am all ears.
Last edited by Rod Serling Fan Club on Thu Aug 06, 2015 4:07 am, edited 1 time in total.
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Karl Welty
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Neon Lamp Synthesis

Post by Karl Welty »

Just finished up this prototype, based on a schematic I found here in another thread somewhere. Its makes all manner of very strange and wonderful sounds but can also sound very much like a conventional multi-oscillator polysynth. Very happy with the results. I've found about 45-50 different types of "things" it does well... and its still a reasonably simple 3 oscillator saw-wave generator. The next version will be more comprehensive. Square wave generators, additional modulation options. Another prototype or two on my way to "the big one" looming in the future.

Image

Image
[/video]
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sduck
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Post by sduck »

Hmmm - is this relevant to this thread somehow, or did you not find the correct thread to put it in?
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andrewF
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Post by andrewF »

sduck wrote:Hmmm - is this relevant to this thread somehow, or did you not find the correct thread to put it in?
assuming they are neon tubes mounted inside the 1/4" sockets, it is quite in keeping with this thread.

Looks pretty good btw - how about a demo :nana:
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sduck
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Post by sduck »

Oh - I didn't realize that they were that small. Yea, sounds?
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Post by andrewF »

about as big as a cap!
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Post by forbin »

It's funny that this post should bubble to the surface.

I bought a couple of Neon tubes in Altronics at the weekend to experiment with a Neon oscillator after Andrew expounded the virtues of the René Schmitz neon VCO (actually I think this conversation was about 5 years ago -- shows how quickly i move)

I must have missed this topic then as there are some really interesting articles here.
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Post by snaper »

A neon LPG???
YEAH!!!
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Post by thermionicjunky »

Rod Serling Fan Club wrote: It may be obvious one could make a sub oscillator using the divide down circuits as well. There are a few examples of the divide down organ circuits floating around.
my favorite suboctave circuit is from the Metasonix TM-3. There is a stability control, which varies the supply voltage to the neon lamps. It's so fucking weird.
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Karl Welty
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Post by Karl Welty »

Neon lamp projects are my very favorite new things ever, and yes... I used 1/4 jacks as mounting sockets. A bit of shrink tube helped keep the leads from shorting against the chassis, and I didnt have the depth in the project box for the other batch of possible lamp bases. Those will be for a larger project.

I did a very quick and dirty sounding demo of the box pictured, but it was prior to the addition of the filter section. The cap in the filter (from the schematic I was working from) is also critical to an aspect of functionality... though it made a variety of delightful noises even as an incomplete circuit.

https://soundcloud.com/karl_welty/neon-synth-mix-1

An example of the finished box with filter has only made it as far as my facebook page. Camera mic in the carport, audio from a guitar amp leaned against my bench. For those not hindered by a FB account, this link may not work unless you are logged in to the collective.



The next box, once I complete the parts list, will be a quad set of dual-lamp oscillators for square waves with pwm and an 8 or 16 step neon counting circuit sequencer.

I've been finding neon circuits delightfully counter intuitive, as they go against so many of the hard and fast rules we are accustomed to when working with audio in a circuit.

The schematic I based it on is included, which I found somewhere on this site but never had a chance to thank the original designer. Its really very clever, and having built it... would be more than happy to discuss the process, my findings, or mods/mistakes I made along the way. So far I have only arc'd two lamps, and let me say that when they go super nova they are quite impressive albeit for only a short amount of time. The characteristics of a half smoked neon lamp are also interesting.

The Metasonix stuff is awesome, Eric is my hero.

Image
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Post by Karl Welty »

Also of note... I used an old piece of German medical equipment as a parts donor for the power supply. 200 volts DC with metering. Funky angled front box that at some point will house some neon foolery but its currently my bench supply for these other projects. I didnt use the power supply shown in the schematic, I suspect its for running the rest of the circuit from a eurorack rail (?) though I cant speak to that with certainty.

The schematic also shows an output tranny on the oscillator circuit. While I have a bag of things which might be appropriate I thought my best chance for success with the first build was going with a voltage divider circuit. Enclosed is what I built. It works well, and I seem to enjoy the sound of the filter. Primitive, but effective in taming a bit of the "zing" neon's tend to have. They are not subtle nor polite, though they can be sublime in their own quirky way.

And also of note... the book by Richard Dorf mentioned at the top of this thread (Electronic Musical Instruments) is a valuable resource which was by my side and referenced frequently during the build process. I wanted to understand the "why" of it, not just "connect the dots".

Image
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Post by waveglider »

A little thinking outside of the box is in order here, you can use neons with an LDR circuit, you just need to use more than one at once!
There is an old circuit that they used to use at Disney theme parks to simulate flame flicker using incandescent lamps. They stuck 6 or 7 NE-22 bulbs together each on its own RC flasher circuit all taped up with a CdS cell and the random flashing of the neons made the 'flicker effect' happen. With the random flashing, there are times when you have more than one lit simultaneously and the resistance fluctuated accordingly.
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sduck
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Post by sduck »

Your video sounds extremely cool!
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Karl Welty
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Post by Karl Welty »

Thank you very much, I am happy as a clam with the results so far. Neon circuits (other than the high voltages involved) can be deceptively simple. What can complicate matters is trying to interface them to devices expecting to see normal range CV's. Since I dont have any gear such as that (can I still hang out here ?) and kind of plan on building up larger systems using neon circuits as the building blocks, the 200 volts aspect doesnt really discourage me.

In the world of deceptively simple, enclosed is a neon counting circuit from the 1965 GE book. Driven by a squarewave pulse (which can be creating with neon using two lamps in a multivibrator arrangement) as a clock signal. Each stage of the chain could fire a tuned neon oscillator, but even more intriguing (to me) is that signal can be tapped off of each lamp in the chain directly... or that each of those could feed into an additional network(s) of counting circuits as trigger pulses. I have yet to benchtest/breadboard this circuit.

A keen upshot of this is that what would require dozens of normal synth modules can be accomplished with a few neon circuits and some creative switch matrix routing options... at least thats my hope.

I imagine that neons firing into LDR's would allow for better communication to devices expecting more standard range CV's.

Image

Image
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Post by megaohm »

Really beautiful!
:yay:

I'll be spending the night searching through the junk boxes for neon tubes.
Crossing fingers!
:hihi:

Thanks to all for the info and schematics, too.
www.MegaOhmAudio.com

Will work for pistachios
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megaohm
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Re: neon tube circuits

Post by megaohm »

andrewF wrote:
The Glow Lamp Manual is here - http://www.electricstuff.co.uk/oldbooks.html
Here's a pic to get things started
neon LPG anyone?
The Glow Lamp Manual pdfs are gone (bad links).
The applications zip is still there.

Can someone who downloaded the PDFs from earlier post them here or send to me, please?
(or are the same as what's in the zip?)
www.MegaOhmAudio.com

Will work for pistachios
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Karl Welty
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Post by Karl Welty »

Glad you enjoyed. It was a fun thing to make and even funner to play with.

This where I found the PDF of the GE book.

https://archive.org/details/GE_Neon_Lamps_1965

I should also note that I used NE-2 type lamps to try and be consistent with the schematic. In theory, other types might take some fiddling with to get them to fire but might also yield some interesting results.

The current limiting resistor is critical, otherwise the lamp will supernova and other bad things may occur. 33k suggested as minimum for NE-2 type lamps.
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Post by whoop_john »

Just a few things about neon ring counters etc.

Firstly you need to condition and batch select your neons for striking voltage. Which means burning in the neons for a day or so and then measuring their striking voltages. Each ring should have a similar set of firing voltages for anywhere near reliable operation.

Secondly, neons often won't fire in the dark. They need some photon excitement in the vicinity. This can be provided by a small LED. I know people have had issues with ring counter neon clocks working at night time.

I was involved in the famous nixie watch that Woz wears. I have one of the first three prototypes and that often won't light in total darkness. Once it has woken up it's OK.

Image

The above issue may cause problems if a neon is encapsulated with LDR in shrink wrap tubing.

Yet I wonder about this. I have an old HP nixie display module that uses a set of small neons looking at LDRs as ingenious BCD to decimal logic decoders and I think that is all housed inside a light-proof box.

Image

As I recall, Hammond used neons in their leslie circuits.

Secondly, small neons are still widely and cheaply available from Russian sources, however these can prove extremely unreliable. Some are designed for DC use only, such as the IN-3 which has a side square that lights, and the INS-1, which has a rather attractive end circular dot.

I have bought thousands of various Russian neons and you can expect maybe 5% of them to flicker immediately or after a very short time. Many have an exceedingly short lifetime. Very frustrating as their characteristics change too much over time.
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Post by Rumblin_Cynth_Rampo »

A friend of mine did some stuff for a BBC Radio 3 program on the music of Louis and Bebe Barron and their score for the Forbidden Planet. He used neon relaxation oscillators and a ring modulator

Here is a clip of his stuff
[video][/video]
No matter how many patch leads you have, you still need a dozen more
http://soundcloud.com/rumblin_cynth_rampo
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