"Tanks" For Nothing!

Thierry: "(tVox: difficult to understand without schematics, the coil is taped but it's no Hartley, Henk: Colpitts)"

Having the tVox in hands, it is difficult to imagine that you,  Thierry, did not perform the reverse engineering, at least in region related to oscillators.

However, knowing that the designer of tVox is russian-educated, russian-erudite, etc., one can most likely assume that  the schematics was taken   (and maybe slightly modified)  from the "Radio" magazine or so.

"However, knowing that the designer of tVox is russian-educated, russian-erudite, etc., one can most likely assume that  the schematics was taken   (and maybe slightly modified)  from the "Radio" magazine or so." Ilya

This is IMO a reasonable assumption -

However, having discussed this theremin with its designer (While having a meal with him and Lydia at the South Bank in 2010) I dont think this is the case..

My understanding is that it was quite an original design, by an extremely skilled electronics engineer whose main job was/is entirely unrelated to theremins or music electronics..

I have no doubt that he did some research - but it seems to me that he approached the whole matter from an "unusual" angle, and came up with something quite different - something he was not willing to give any strong hints on..

As I say, I suspect something quite unusual and/or original - we discussed many issues in the "public domain" and shared some information not within that 'domain' - in particular we discussed how I had 16 theremins running together without interference, and that led to some clues...  , but I would not be at all surprised if something in his design he cannot disclose because it is being used in some other capacity (far more commercially valuable than theremins) and disclosure would be foolish. I had the strong feeling that he would be happy and even wanted to talk about it, but was not able to.

But I could be completely wrong! ;-)

Fred.

(my guess, based on what I think may have been a few clues, is that there is a clever feedback mechanism between the pitch and reference oscillators which implements linearity correction - it may be that the taps are part of such a mechanism, if it exists...)

The other thing which was interesting was his total refusal to even think about building another batch of Tvox, or to licence the design so that anyone else could build them.. I had a long careful evaluation of the economics, and the fact that there was no money in it - that a batch of 100 required to make the venture economic would be too risky..

He is a wise man! ;-)

"The other thing which was interesting was his total refusal to even think about building another batch of Tvox, or to licence the design so that anyone else could build them.. I had a long careful evaluation of the economics, and the fact that there was no money in it - that a batch of 100 required to make the venture economic would be too risky.."  - FredM

This unfortunately seems to be the way most Theremin production goes.  Designer beavers away in the lab for several years, manufactures some, then stops due to economic reasons.  The EWS seems to be the major exception, but it has a larger electronic musical instrument company behind it.

With the mystique the TVox has going for it, I'd think they could get $800 or so a pop.

"With the mystique the TVox has going for it, I'd think they could get $800 or so a pop" - Dewster

The Tvox was. by a long way, the nicest and easiest theremin I have ever played -

But at $800 even if there was $400 profit on each (which I doubt there would be) 100 SOLD units would bring $40k total profit.. I recon  one could be sure to sell perhaps 50 over the first year - but the remainder?

George strikes me as someone who can probably earn the entire return of such a venture in a few months, with a lot less bother - And as someone who only did the first batch for Lydia and her students, that was his motivation, not money.

Unlike those here (and I include myself) on some obsessive "journey", George seems, to me, completely free from any dellusion or obsession about the theremin or any commercial viability of the theremin.

And I suspect his opinion is that the theremin development or manufacture  is just too much bother for anyone who has a real life.

:-)

Fred.

"But at $800 even if there was $400 profit on each (which I doubt there would be) 100 SOLD units would bring $40k total profit.. I recon  one could be sure to sell perhaps 50 over the first year - but the remainder?"  - FredM

Well, $40k USD would keep me going for a couple of years! :-)  I'm approaching this as more of a potential cottage industry that one person can mange rather than a replacement for what I could make in the private sector (I used to make >$100k/yr, *sniff*). 

I'm thinking the trick is to make two units - a stripped down minimal unit at a rock bottom price (~$250-$450) for the feet wet crowd, and a kitchen sink unit at a premium price (~$500-$1.5k) for pros.  For the pro model put an air coir coil on the pitch side and a second axis on the volume side.  Both could have LED pitch indicators and linearization software.

Hi Dewster,

Yeah - I am in the same 'state' as you, $40k would be enough to keep me at tickover for a couple of years - and the " cottage industry " basis is the only realistic one for theremins I guess..

My evaluation is that its the sub "feet wet crowd" where the only real money might exist - IF there is a "large" market, its in the sub £100 ($161) or perhaps sub £150 zone - And there are a few theremins (LV-3 and Burns for example) within this zone - I doubt that the combined income from those gets anywhere close to what any investor would be interested in, even if the newcomer grabbed the entire market! - its the "toy" end, where little care  and minimal time to calibrate / check etc is required, that the biggest markup can probably be made - and the largest volumes sold.. things which make unplayable noises as hands get near to them.

Its not just about designing and producing - its also about marketing and supporting.. Most of the sub £100 rubbish is probably impulse buy, and if people dont like what theyve bought they are likely to forget it.. Not so much the case I think above £150 - Above a 'line' somewhere 'round there, one needs good marketing and good reputation (which takes time) and a good support network.

And all the above is expensive and will eat into whatever pennies one manages to make.

I think you can engineer a digital theremin as good or better than equivalently priced analogue theremins - but suspect that quite a large % of potential purchasers will be more cautios about buying yours at the prices you are proposing - simply because, as you have rightly (IMO) highlighted, the digital stuff to date has been (again, IMO) horrible - I, for one, would be really worried about spending my money on a digital theremin instead of buying say an EW IF I didnt know the technical abilities of the designer - So I would (at this time) only buy one from you ;-) .. but im not in the market for a theremin ;-) ... One of my main reasons for me staying inclined to  analogue is the knowledge that I could get into it and change things - this aint so easy if theres one chip inside that does everything...

I think its a really small pond, and there are two main groups of fish in it - those who will eat anything as long as its cheap, and those with 'better' taste - but those with 'better' taste dont have anything they all like - they are a fussy lot, some with crazy predudices and ideas .. So whatever one wants to "feed" them, there will only be a tiny number in this small pond who will be interested... The question is, are there enough in any group in the pond to make producing something for them commercialy viable - even for a cottage industry?

I suspect the answer is no - But this wont stop us, will it ?! 

;-)

Fred.

ps .. There is one other group I forgot to mention, and it may be quite large (compared say to those interested in really high-end theremins for example) - these are the DIY / Hobbyist / EE Enthusiasts / Kit builders etc.. I think that both analogue and digital theremins are food for this group - They are (possibly) more interested in the technology and learning / playing with this, than they are in the musical attributes of the technology (although some may be upset by this statement, and some will have  musical interest and aspirations as their primary motivation)

pps .. The Tvox is a great instrument, and what I say here is absolutely no attempt to denegrate it or dishonor it or its designer in any way...

But I do wonder whether if someone else had built it, without the huge boost to its exposure given by it being Lydia's theremin, it would have been so well known and respected.

The fact that even with this boost (marketing / reputation) and its massive exposure on youtube etc, its designer has no interest in a repeat performance and thinks that even a run of 100 might be difficult to clear, to me speaks volumes..

How many Tvox, produced by some newcomer, would have sold? I think they came to market at about £800 (but this is just something I heard, could be entirely wrong..) .. How many Evox or E-Pro's sold over their first year after production started? - and they were from Bob Moog!

The numbers arent good -

Fred, you're too kind to me, but I very much appreciate it.

Truth be told I might be happiest building just one million dollar Theremin for a billionaire, and take 10 years to do it - that's what my current (non-existent) development roadmap seems to be based on anyway!

"I might be happiest building just one million dollar Theremin for a billionaire, and take 10 years to do it -" - Dewster

LOL ;-) .. You share my dream!

But finding such a billionare - particularly one willing to put even 10% up front, well - I havent had any luck so far!

;-)

Fred.

 ps.. your comment got me thinking.. If I was to make ONE high end theremin based on my R+D to date, and sell this at a price which recovered my expenditure / loss of income (as in, what I would have earned IF I managed to find non-defence work paying reasonable wages, instead of spending my time on theremins) then I would need to add at least £250k to whatever that theremin cost to build!  The $1M theremin might even be a "bargain", LOL ;-) ... But its sobering.. realizing that there is no possible way to recover the investment - thats written off.. Question is, from this position, even writing off the "losses", can I go forward without losing more? .. The answer is no - not with theremins.. perhaps with "spin off" from the theremin R+D I can though...

"But its sobering.. realizing that there is no possible way to recover the investment - thats written off.. Question is, from this position, even writing off the "losses", can I go forward without losing more? .. The answer is no - not with theremins.. perhaps with "spin off" from the theremin R+D I can though..."  - FredM

From a business standpoint every minute spent learning and not doing is a loss! ;-) 

From from a personal standpoint the learning is the thing IMO.  Theremin research can be tremendously beneficial in this regard (and fun!) but at some point it's time to move on.

Now you've got me thinking I should make the most feature rich, least expensive to build Theremin that I can.  A big impediment is the case, which would have to be a standard manufactured one to keep it simple.  Fred, you pointed to ALTINKAYA a while back and they seem to have some very nice offerings.  This display box might make for an interesting enclosure  (though shipping for small quantities is more expensive than the enclosure itself).  All plastic to keep sensitivity high, big display area (perhaps too big) that one could perhaps mount controls on as well. 

I think I would also need some kind of small plastic spool that would fit over the end of a Bourns 6300 inductor (OD ~7.4mm) so as to sense resonance with an extra winding (I've been hunting plastic sewing machine bobbins, but can't find a list including this dimension anywhere).

Hi Dewster -

Yeah, that box looks like an interesting option - particularly for a digital theremin, and at a good price, and I think one could easily mount controls on the display area (would need to, as theres nowhere else for controls to go) and still have enough space for a reasonable display.

"I've been hunting plastic sewing machine bobbins, but can't find a list including this dimension anywhere"

I have also found the same thing - I ended up buying a load of different ones on Ebay and Amazon, just so I could measure them! I was looking to insert ferrite cores into them (this was back when playing with the RCA clone), and did find one which did the job, but never found anything suitable for the Bourns 6300 - I ended up putting sense and DC bias windings directly onto the two 6300s closest to the oscillator - windings between the first two existing coils - Yes, this does cause some increase in capacitive coupling between these two coils, but the later coils made up for this.

I never used the above to sense resonance though - used it in early experiments with electronic tuning of the inductors using DC current  to shift the operating point on the BH - I use current monitoring on the oscillator power to determine resonance.

I ended up using EPCOS formers in the end - a lot more expensive than sewing machine bobbins, but at least you can find data on them - there are a fair range of different types - something like an RM7 or RM8 or one of the EP may suit your requirements (The RM8 former does fit over the 6300 ferrite but is a bit loose, so coupling isnt great - theres about 1mm gap.. I think its got an 8.6mm ID.. An RM7 might be a tight fit) - these RM formers are in the order of £1 and available from many manufacturers and suppliers in all sorts of configurations,

Fred.