looking for part for Moog's 1954 theremin

Greetings to everyone,
I'm looking for parts to build a theremin from
a 1954 article in Radio and TV News, by
Bob Moog. In particular, I'm having trouble
finding a Stanwyck horizontal oscillator coil
(LHO 2). I'd appreciate any advice from anyone
who has built this theremin or who knows
where to find this part, an equivalent or
specifications for this part.
Thanks,
Kevin

I built one of these theremins many years ago. I have two of the coils required to make this thing and will be glad to measure the inductance range for you. I built mine in the '70s and had to have the coils wound. The theremin works well and is now used in a rock band. Let me know.

Mark

Mark, thanks, I would like to
know the inductance value of
those coils. It seems they're
very hard to find, but I could
wind something equivalent.
Kevin

Kevin,

The inductance range is 10 mH to 35 mH. The dimensions of the winding are: 0.7 in diameter by .635 in long on a 3/8 in form with a 5/16 in diameter by 11/16 in core. Wire size is #30. I found a source for some that might work (no guarantee) from Surplus Sales of Nebraska, part no. (IVF)7167685G1, 10.5 to 46.6 mH and physically similar to what you need. Not cheap at $25 each. I had to have mine made special by the original manufacturer, 25 coil minimum so I used 2, kept 2, and eventually threw the rest away. Who would ever need them? Sure. I have been toying with the idea of building another one.

Mark

Mark, Thanks for the information, that will
definitely help. I have a couple Miller horizontal oscillator coils that I'm thinking
of trying as a substitute. Their inductance range is a bit more restricted, 17mH to 34mH. The length of the winding is nearly the same,
but the diameter is a bit smaller (0.6 in.).
The core has a bit smaller diameter as well.
It seems like it might be worth a try though. Thanks for the information. I'll post my results
to this forum, when I try it (It might take
a while).
Kevin

Hello Mark,

Kevion notified me of your posting concerning the Moog tube theremin coil specs.

When you say you had your coils made by the original manufacturer, do you actually mean Stanwyck??? I did not even know they were still around.

More importantly, can you please tell me if the specs you gave are for the coils before or after the modification specified by Moog (removing certain number of windings from L8 until 30 ohms resistance achieved)? You see, the size you gave for them differ from the size from Moog's drawing for the Radio & Television news article. So what I actually need to know, is: if you started out with coils of the physical size as posted by you on this forum, how much wire or how many windings did you remove from L8, or did you unwound until 30 ohms was achieved?

If you want to part with the two coils you have left, please let me know; unless of course Kevin would like to buy them.

Kind regards and thanks very much so far,

Aaron

Aaron,

I built the Theremin in the mid '70s and Stanwyck was still around when I had the coils made. I would be surprised if they are still in business. The dimensions and impedance values I gave are of unmodified coils. The DC resistance of the unmodified coil is 51 ohms so this would give you an idea of how much to remove from a substitute coil. I would think that any coil of similar dimensions and impedance modified proportionally would work. In a pinch coils could be wound. I have been thinking of building another one so will keep the coils I have for now. Sorry.

Mark

Are you still interested in locating the Stanwyck LHO-2 or equivalent?

Hello Andrew,

Yes I am in fact. The plan is otherwise to use the information above to construct some coils completely from scratch, but getting the foundations proper for the oscillators can't hurt...

Aaron

If you will give me your email address, I can provide the cost for a pair of the coils. I tried to reach you directly by clicking on your name on the left column in this forum, but it comes up as hidden. I've had some difficulty with this before on this site, so it may or may not have to do with your preferences.

Best regardds,
Andy