Is Moog still making Theremins?

Am looking around again today, nothing new except for Thereminis (blea).  It's extra tough out there for a Thereminist these days.

For some reason which I am as of yet unable to ascertain, Thereminworld seems to cover everything and everybody theremin except for my company which has been around since 2014. Perhaps I managed to hack someone off in some other forum that was busy spewing their minutia? I have had correspondence with Therminworld so they know I exist.

We offer our own clone version of the original Etherwave and I think I'm the only one left on the planet doing anything to keep the original Keppinger design alive. I am in the process of doing a redesign on the Etherwave because the Pi wound chokes in the aerial circuits have been discontinued by Hammond Manufacturing and the variable inductors in the oscillators have been discontinued by Coilcraft.  All the new designs coming out of Moog music are more computer than they are theremin!

www.thereminbuilder.com

"For some reason which I am as of yet unable to ascertain, Thereminworld seems to cover everything and everybody theremin except for my company which has been around since 2014."  - glenlivet

I must admit that this is the first I've heard of your company.  I can't imagine that was caused by anything malicious going on here at TW though.

"I am in the process of doing a redesign on the Etherwave because the Pi wound chokes in the aerial circuits have been discontinued by Hammond Manufacturing..."

What is your plan to replace the Pi wound RF chokes?  I've looked around the web for coil design software but haven't found anything that will predict how a multi-element basket weave with ferrite core will spec out (L, self C, Q, proximity effect, etc.).

"All the new designs coming out of Moog music are more computer than they are theremin!"

Agree, and now it's just down to the Theremini, unfortunately.

"Agree, and now it's just down to the Theremini, unfortunately."

...and I've read a lot of unhappy reviews about those.

Finding RF components for the frequency range that theremin oscillators typically run at is dang near impossible these days.
Mouser Electronics has even dropped their line of miniature IF transformers so I would assume that when the stock runs out the Paia Theremax
most likely will too.
   
I'd hate like heck to be in the business of manufacturing AM/FM terrestrial broadcast radios. If you want stuff that works upwards of 2.4 Ghz however,
NO SWEAT!

The most radios for any purpose today are SDR and use only good low im3 preamps following by bandfilters at the input,
than all is digitized e.g. for example getting i/q signals by a Tayloe mixer followed by simple baseband ad-converters.
Some use mixers after preamp and bandfilter to get it even lower in frequency and continue after this.
It all made very very large steps in intermodulation and near signal reduction not comparable to the superhet mixer scheme since 1999 i would say.
First methods have been patented and got therefore not available for everybody for years.
The funny thing is in contrast to patending new principles of function of a circuit the principle can be patended but not the circuit itself
That's also why everybody can commercially use any circuit he gets to know when there is no patent on the principle

73 (greetings in ham slang) de Chris DL6SEZ

60 seconds seems kinda long, is there some sort of slow averaging going on?  How often do you have to calibrate it? - Dewster (about open theremin)

60 seconds is a kind of upper limit when the algorithm doesn't converge quickly (for obscure reasons). This is an iterative (but not dichotomous) process. Each step consists in measuring the frequency by counting the oscillations during 1 second, calculating and setting a value for the varicap. For pitch and volume successively. I wonder if we couldn't shorten each step to 100 ms, for example... We calibrate it quite often because of thermal drift, so a less time-consuming calibration would be great.

Open theremin is a very good start for a theremin (value for price, field geometry, ...) but it is not its mission profile to replace the etherwave.

"73 (greetings in ham slang) de Chris DL6SEZ" - chrisbei

Chris, you being a ham and all, I'll ask you the same question: Are you aware of any software / equations / etc. for designing Pi wound RF chokes?  Something that even roughly predicts L, Q, self C, etc.?  I have no clue how Hammond / Bourns were designing their offerings, though I suppose a lot it could have been just a pile of trial and error for certain target L values, followed by interpolation for intermediate values once trends were established.  That, and simple industry copying once optimal configurations were found.

Hello dewster,

no sorry i have yet not found a calculation estimation for those three cross wound coils in series on one iron powder core. Will have a look in german again these days.
It  has, as i remember, nothing to do with a pi network.
The low capacitance coupling between the windings on each coil block itself is due to cross winding. The result is on every winding the potential difference to the winding below is minimized due to it's only facing lowest potential difference directly. This is opposite to a linear wound coil. The distributed capacitance of each coil winding to coil winding is therefore minimized in two ways, mechanically and electronicaly (lower potential difference). They were used in flat form on old non active low wave detector receivers. The three coils in series doing this additionally due to there space in between. 
Cross winding is still used in advanced high power techniques. For example military rocket power supplies (radar pulse generators 5kW peak in ("Patriots" for example). For this old product i can tell this from my fellow electronics engineer ham colleague which worked at Telefunken Defense Systems (company had many different names in the last years, also made the electronics for the E-3A Awacs... company is still in same buisness here in Ulm Germany).

I found a german shop where you could ask for manufacturing them, until now found nothing more.
The shops page with coils:

https://www.jahre.de/de/produkte/induktivitaet/bauform-73/

"no sorry i have yet not found a calculation estimation for those three cross wound coils in series on one iron powder core. Will have a look in german again these days."  - chrisbei

I've looked and looked, and either I'm not seeing it somehow, or more likely the algorithms are lost / proprietary / internal.  They used to sell cross-winders to hams, I wonder how the hams knew what to do with them?

"It  has, as i remember, nothing to do with a pi network."

Right.  I don't get where the Pi terminology came from though.

"The low capacitance coupling between the windings on each coil block itself is due to cross winding. The result is on every winding the potential difference to the winding below is minimized due to it's only facing lowest potential difference directly. This is opposite to a linear wound coil. The distributed capacitance of each coil winding to coil winding is therefore minimized in two ways, mechanically and electronicaly (lower potential difference). They were used in flat form on old non active low wave detector receivers. The three coils in series doing this additionally due to there space in between."

Yes, the cross winding keeps wire layers from running in parallel and spaces them out, both of which lower the proximity effect, as do the separate "donuts".

"Cross winding is still used in advanced high power techniques. For example military rocket power supplies (radar pulse generators 5kW peak in ("Patriots" for example). For this old product i can tell this from my fellow electronics engineer ham colleague which worked at Telefunken Defense Systems (company had many different names in the last years, also made the electronics for the E-3A Awacs... company is still in same buisness here in Ulm Germany)."

Interesting.

"I found a german shop where you could ask for manufacturing them, until now found nothing more.  The shops page with coils:  https://www.jahre.de/de/produkte/induktivitaet/bauform-73/"

Wow, thanks for that!  Largest L is 10mH which would be useful.  Though the Q seems somewhat lower than the Hammond / Bourns coils used in the Etherwave.  No one ever supplies temperature drift data with these things.

"60 seconds is a kind of upper limit when the algorithm doesn't converge quickly (for obscure reasons). This is an iterative (but not dichotomous) process. Each step consists in measuring the frequency by counting the oscillations during 1 second, calculating and setting a value for the varicap. For pitch and volume successively. I wonder if we couldn't shorten each step to 100 ms, for example... We calibrate it quite often because of thermal drift, so a less time-consuming calibration would be great."  - Mr_Dham

I wonder if it could be a progressive thing?  Start with a short count time and get it roughly calibrated, then increase the count time as it gets closer to in-tune?  This is a feedback system so it can likely be analyzed and optimized to some degree from a linear model.

"Open theremin is a very good start for a theremin (value for price, field geometry, ...) but it is not its mission profile to replace the etherwave."

Understood, and good point!

Vincent, do you know what the hardware frequency measurement resolution is on the Open Theremin?  For instance, the D-Lev resolves to ~2.5ns (I/O is clocked at ~400MHz).