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 Post subject: Tube Only Color Organ
PostPosted: Jan Mon 22, 2018 10:26 am 
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Location: Los Angeles
Of course, I'm not the first to do this. There's a project article, on it from 1959:

https://threeneurons.files.wordpress.co ... -organ.pdf

But this circuit has some deficiencies, that possibly propagated into the solid state circuits, of the 60's and 70's:

Image

The main problem, is that both thyratrons & thyristors (TRIACs & SCRs), are either ON or OFF. No linear section. That means brightness is adjusted by using some for of pulse width modulation (PWM). When using AC line voltage, the device turn-ON is delayed (per cycle) relative to the desired brightness. Earlier in each cycle for brighter output. This is how your everyday household lamp dimmers work.

But for some reason, this never made it into color organ circuits. In those circuits, if the music is loud enough, it turns ON the light. If it ain't the light stays OFF. Pretty hap-hazard.

In recent years, I've made TRIAC versions of the color organ, that DO properly convert the audio level, to the corresponding phase angle, in each half AC cycle.

I've been wondering if proper control could have been done with tubes only. That means thyratrons. I've purchased several types, in the last few months. I've already had 2D21s and 2050s, in my stash, but bought beefer 6012s, 6014s (aka C1K), and 5559s for some serious current switching. I just finished a "proof of concept" circuit, and here's the results:

Basic concept:
Image

My thyratron page:
https://threeneurons.wordpress.com/misc ... hyratrons/

And a video of the working circuit:
https://youtu.be/z7YYyiGx9Gg

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 Post subject: Re: Tube Only Color Organ
PostPosted: Jan Mon 22, 2018 10:47 am 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Albuquerque, NM 87123
Let me be the 1st to say: So What?


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 Post subject: Re: Tube Only Color Organ
PostPosted: Jan Mon 22, 2018 2:41 pm 
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Location: Yukon, OK USA
We certainly have a diverse set of interests here. I have built several color organs. Don't think it ever occurred to me to do it with tubes. Thanks for sharing.

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Rick
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 Post subject: Re: Tube Only Color Organ
PostPosted: Jan Mon 22, 2018 3:49 pm 
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Location: Mount Pleasant UT 84647 (from Coventry, UK)
I like your choice of music!


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 Post subject: Re: Tube Only Color Organ
PostPosted: Jan Tue 23, 2018 12:26 am 
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Location: Tucson, Arizona U.S.A.
I have an Audio-Vision model H SonoScopE commercially made tube color organ. I haven't restored it yet and, unfortunately, I have no documentation on it so my knowledge of the circuit is minimal. The tubes are 2X 6SL7, 3X 2050, 117Z6. The lights are 6X 313. Even though it has a power transformer, it is not isolated from the AC line.


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 Post subject: Re: Tube Only Color Organ
PostPosted: Jan Tue 23, 2018 2:15 am 
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Location: Mount Pleasant UT 84647 (from Coventry, UK)
Jim, that's an interesting piece of hardware. I've never seen or heard of anything like it.


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 Post subject: Re: Tube Only Color Organ
PostPosted: Jan Thu 25, 2018 4:10 am 
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Location: In the village, 19115
The designs on that disc are very interesting, you should try to carefully clean it and try to scan it. That's pretty cool!

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I like things that light up, tubes, bulbs, LEDs, whatever, and things that make noise.


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 Post subject: Re: Tube Only Color Organ
PostPosted: Jan Thu 25, 2018 7:24 am 
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Location: Tucson, Arizona U.S.A.
When I first got it back in the late '60s or early '70s, I tried it out. The patterns on the disk with the lights behind it give an effect sort of like rising, colored smoke.

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 Post subject: Re: Tube Only Color Organ
PostPosted: Jan Fri 26, 2018 5:14 pm 
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Joined: Nov Wed 30, 2016 7:35 pm
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Location: OHIO 43074
If you REALLY want to do this with tubes, it should include a CRT display :-D .... just tryin to help

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 Post subject: Re: Tube Only Color Organ
PostPosted: Jan Sat 27, 2018 7:15 am 
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Location: Los Angeles
Colin Ames wrote:
I like your choice of music!


I'm guessing Pink Floyd, and not Mojo. :D

Jim Mueller wrote:
I have an Audio-Vision model H SonoScopE commercially made tube color organ. ...


Neat piece of kit ! ... and made in Pasadena, too ! I grew up in that town, and lived there for a while, too.

Barry H Bennett wrote:
If you REALLY want to do this with tubes, it should include a CRT display :-D .... just tryin to help


I'm trying to put this project "to bed". Next planned project, coincidentally, is a scope, from scratch, using an old electrostatic CRT. I have a decent stash. from a 1" 1CP1 (right behind me, right now, on a shelf), to a pair of 5CP1s, and another pair of white phosphor 5UP4s. Also a bunch of 2" and 3" tubes, in between.

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Life is like a roll of toilet paper - The closer you get the end, the faster it goes - A.E. Neuman


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