Let's talk about the Subscope theremin!

What a nice idea! Opto-coupler for voltage dividing via the two photo-resistors? Let's found a creative club! 

Oh well, that double photo resistor has not been my idea. I spotted it in a filter scheme and at least have implemented it into the VCA..

But this is by myself:

Dominik,
What is the difference between this model and the Voicematic 3 of 10 years ago?

Brian,
no or not to mention changes on the pitch side. More changes on the volume side: since 2016 velocity is on-board as a standard feature coming along with some extra range. Since 2016 white noise and since 2017 2nd harmonic are optional add-ons. Some years ago my beloved 2N5484 FETs in the TO92 housing had been discontinued and all of a sudden 2021 the same game over for the SMD variant MMBF5484. I quickly bought a few hundreds. The same bitter fate for the audio amplifier i am using for pitch preview and luckily i came across a nice offer – even for the DIL variant. From time to time i wonder what might happen with the digital theremins in a few decades when they may loose their brain (FPGA? i am not into this terms) but non availability of good old analog components baffles me as well.

Anyways: war in europe. Very sad.

Adaption of the SMD FET for the slot:

A hopefully delight: As long there are universal transistors, copper wire, resistors and capacitors we will be able to build theremins. :-) 

What is the function of the noise generation? To be mixed, added to? 

The volume of pitch and noise independantly can be mixed.

"A hopefully delight: As long there are universal transistors, copper wire, resistors and capacitors we will be able to build theremins. :-)"
Word!

"Some years ago my beloved 2N5484 FETs in the TO92 housing had been discontinued and all of a sudden 2021 the same game over for the SMD variant MMBF5484. I quickly bought a few hundreds. The same bitter fate for the audio amplifier i am using for pitch preview and luckily i came across a nice offer – even for the DIL variant."  - DOMINIK

I'm experiencing this same crazy supply situation.  Zero inventory with expected dates often two years out.  It seems everyone is snatching up everything available, and I'm having to play that game too.  Going directly to TI has provided me a supply of the tuner LED drivers; Microchip the EEPROMs.  I'm overbuying & hoarding and don't like it at all as I'm likely depriving others of these parts I'll just be sitting on, though  I guess I could resell them at some point.

"From time to time i wonder what might happen with the digital theremins in a few decades when they may loose their brain (FPGA? i am not into this terms) but non availability of good old analog components baffles me as well."

I believe FPGAs will be with us for a long time to come, they fill a very plastic niche for logic.  Not the fastest nor the most power efficient, but often nothing else outside of an extremely expensive and risky custom IC will do.  The problem is buying them at reasonable prices and getting them soldered to a board.  Another problem is the very complex software tooling they require, and parts from different manufacturers aren't very interchangeable in terms of the hard on-chip peripherals.

"Anyways: war in europe. Very sad."

Poor Ukraine, it's awful.

"A hopefully delight: As long there are universal transistors, copper wire, resistors and capacitors we will be able to build theremins. :-) "

I envy you, you've definitely got it easier than me!

I'm probably violating the rules here but my heart and prayers go out the the Ukraine and all of Europe....especially our friend Dominik. I can't imagine what it must be like living under that dark cloud. These atrocities effect everyone on the planet.

Thanks Brian! It's the Ukraine in the need of help and prayers for sure.