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26th Jan 2021, 11:10 am | #1 |
Hexode
Join Date: Dec 2017
Location: South East London
Posts: 301
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Simple valve oscillator for a valve organ?
For my dissertation, I’ve decided I want to attempt to build an organ using valve oscillators.
Is there any simple oscillator circuits out there which can achieve a full frequency octave or 2?
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With regards, Ed |
26th Jan 2021, 12:51 pm | #2 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
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Re: Simple valve oscillator for a valve organ?
I recall that there were various articles on building organs in magazines such as Practical Wireless 'back in the day', it might be worth doing a trawl through them online.
Andy |
26th Jan 2021, 1:56 pm | #3 |
Dekatron
Join Date: Aug 2003
Location: near Reading (and sometimes Torquay)
Posts: 3,094
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Re: Simple valve oscillator for a valve organ?
Do you mean a fixed frequency oscillator as was usually done for polyphonic organs, or a single oscillator that is tuned by the keyboard (like the Clavioline)?
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26th Jan 2021, 8:54 pm | #4 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,194
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Re: Simple valve oscillator for a valve organ?
Hi Ed, a few booklets were available on the subject from Foulsham-Sams
Also The electronic musical instrument manual Douglas 1949 Frequency divider organs Douglas 1963 Electronic musical instruments Lewer from Electronic engineering I think Douglas wrote for Radio constructor; most of the journals had the odd article in them about musical instruments, World radio history site is you friend here, if you have the time The ones mentioned above outline a variety of techniques for note generation in both simple and complex manners, as well as details of the filters used to give the various "voices" At grammar school in the 60's the electronics club started building one for the school, but it was still unfinished when I left from upper 6th Ed Last edited by Ed_Dinning; 26th Jan 2021 at 9:02 pm. |
27th Jan 2021, 5:30 am | #5 | |
Hexode
Join Date: Dec 2017
Location: South East London
Posts: 301
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Re: Simple valve oscillator for a valve organ?
Quote:
As I want mine to be polyphonic, each note would need to have its own oscillator and a set frequency. I could do a monophonic type with just one oscillator but it seems a waste to have 2 octaves and not able to play anything
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With regards, Ed |
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27th Jan 2021, 5:31 am | #6 | |
Hexode
Join Date: Dec 2017
Location: South East London
Posts: 301
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Re: Simple valve oscillator for a valve organ?
Quote:
I’ll have to do some research! Thanks
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With regards, Ed |
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27th Jan 2021, 5:33 am | #7 | |
Hexode
Join Date: Dec 2017
Location: South East London
Posts: 301
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Re: Simple valve oscillator for a valve organ?
Quote:
My idea is to just have some very basic oscillators forming 2 octaves worth of notes. Do you know if these booklets are available online? Thanks
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With regards, Ed |
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27th Jan 2021, 7:18 am | #8 |
Heptode
Join Date: May 2017
Location: Konongo, Ghana
Posts: 514
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Re: Simple valve oscillator for a valve organ?
Looks a bit like repeating this thread: https://www.vintage-radio.net/forum/...d.php?t=174169
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Robert |
27th Jan 2021, 11:27 am | #9 |
Hexode
Join Date: Nov 2003
Location: Ossett, West Yorkshire, UK.
Posts: 482
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Re: Simple valve oscillator for a valve organ?
I worked on one from the early sixties. It was polyphonic. Each note and half note had its own inductor tuned oscillator and each oscillator drove 5 dividers, one for each octave.
It drifted like crazy and had to be retuned very often |
27th Jan 2021, 12:15 pm | #10 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
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Re: Simple valve oscillator for a valve organ?
Lucien Nunes has a commercially made one. You might like to do a search for his threads here on the forum. It's a monster and will give you an idea of what you're taking on. I think it uses the butler oscillator circuit. LC tuned circuit feeding the grid of a triode, with the cathode driving a tap on the inductor.
David
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27th Jan 2021, 6:14 pm | #11 | |
Dekatron
Join Date: Aug 2003
Location: near Reading (and sometimes Torquay)
Posts: 3,094
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Re: Simple valve oscillator for a valve organ?
Quote:
You might want to do the maths and calculate the cost before deciding to use ICs. |
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27th Jan 2021, 6:26 pm | #12 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
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Re: Simple valve oscillator for a valve organ?
For your dissertation?
What in? Presumably you have to be able to demonstrate some original research or original development. I've seen a number of cases where people chose their favourite hobbies for projects and theses/dissertations where they didn't get good grades because of lack of original work. Take care and have a chat with your course supervisor so you're clear on just what you need to achieve. A little steering in the beginning can have a big effect later. David
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |
28th Jan 2021, 5:44 am | #13 |
Hexode
Join Date: Dec 2017
Location: South East London
Posts: 301
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Re: Simple valve oscillator for a valve organ?
It’s a bachelors degree in Music production, however the brief is pretty broad, which allows pretty much anything to be done as long as it releases to music, but main work which would need to be handed in now is mainly designs and plans.
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With regards, Ed Last edited by Radio Wrangler; 28th Jan 2021 at 8:39 am. Reason: Post corrupted by my error. some text missing. David |
28th Jan 2021, 5:48 am | #14 | ||
Hexode
Join Date: Dec 2017
Location: South East London
Posts: 301
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Re: Simple valve oscillator for a valve organ?
Quote:
I recently scrapped a portable ekco valve tv, which has quite a large mains tx. I agree with you, a lot of circuit for not a lot of functionality. I’m trying to locate a practical tv mag guide on a simple design which I can develop from, any coils chokes needed, I’m sure I could ask Ed dinning or mike barker to make for me. It’s a bit of fun at the end of the day, I might even get it finished! Lol
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With regards, Ed |
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28th Jan 2021, 8:39 am | #15 | |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
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Re: Simple valve oscillator for a valve organ?
Quote:
https://www.vintage-radio.net/forum/...d.php?t=121108 The rack of oscillators is as overwhelming as the monolith in 2001 David
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |
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2nd Feb 2021, 1:18 am | #16 |
Heptode
Join Date: Oct 2005
Location: Olympia, Washington, USA.
Posts: 664
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Re: Simple valve oscillator for a valve organ?
I suspect you could copy the oscillator circuits from a commercially produced organ. Likely the patents have expired, but check first.
The ones I worked on (decades back) used 6SN7, 12AX, AU7, or 6CG7 dual triodes as the osc tube. I rebuilt a Minchel Organ for my mother back in the late 70's. Basically the osc circuits were really simple. I don't have the service data anymore though. |
3rd Feb 2021, 11:13 am | #17 |
Pentode
Join Date: Jul 2009
Location: Brightlingsea, nr. Colchester, Essex, UK.
Posts: 209
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Re: Simple valve oscillator for a valve organ?
There's a design in Practical Wireless October 1953, if that helps.
Bryan |
3rd Feb 2021, 3:40 pm | #18 |
Hexode
Join Date: Nov 2003
Location: Ossett, West Yorkshire, UK.
Posts: 482
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Re: Simple valve oscillator for a valve organ?
Nice simple R-C oscillator does not need inductors. the parts list is in the February 1954 edition. Some values might be hard to find but could be made up of multiple values.
The articles are available free here https://worldradiohistory.com/UK/Pra...PW-1954-02.pdf As an aside, I really enjoy the 'On Your Wavelength' topics by Thermion, Some of the comments are as relevant today as they were back then. |
3rd Feb 2021, 4:09 pm | #19 |
Nonode
Join Date: Aug 2015
Location: Cambridge, Cambs. UK.
Posts: 2,198
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Re: Simple valve oscillator for a valve organ?
A feature of a valve-based electronic organ is going to be some pretty wide temperature variations as it all warms up. So an outline study of the temperature stability of different oscillator circuits might make an appropriate chapter. It would be interesting to compare the figures with the typical temperature stability of a pipe organ.
Martin
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3rd Feb 2021, 6:17 pm | #20 |
Dekatron
Join Date: Aug 2003
Location: near Reading (and sometimes Torquay)
Posts: 3,094
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Re: Simple valve oscillator for a valve organ?
I think you might get more fun from a monophonic synthesiser type of circuit. There is so much more scope for interesting sounds. Building something like a Moog using valves will be interesting!
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