Best synthesizer for theremin

Posted: 8/30/2020 5:31:51 PM

From: Berlin Germany

Joined: 4/27/2016

Thierry, thank you for this insight. Do I understand correctly that the E-Pro creates its sound by reproducing mixed sharp rectangular signals? How is the excellent temperature stability achieved?

Posted: 8/30/2020 8:32:11 PM

From: Colmar, France

Joined: 12/31/2007

I wrote everything above: Both pitch oscillators’ sine waves are sent through LM393 comparators to transform them into 5Vp square waves. These are fed into 74HCT393 dividers. Then, the original signals, their divide-by-two, and their divide-by-four outputs are sent to 3 respective 74HCT86 XOR gates as mixers. Their three raw output signals (original pitch, one octave down, two octaves down) go to the register switch whose return goes through a passive 12dB/oct 2xRC low pass filter with a corner frequency of ~14kHz which gives a relatively clean but slightly rounded triangle wave. Afterwards, it’s some biasing and the LM13700 wave shaping stuff which we know already from the E-Standard. Finally an additional LM13700 acts as a voltage controlled filter, before it goes to the VCA section which is again LM13700 based.

The temperature stability is achieved by 3 means: First, both pitch oscillator transistor pairs are fed through current mirrors on their common emitters. This makes that when they drift, they’ll drift together and the heterodyning difference will remain the same or almost. Second, the same ugly capacitance multiplier (variable reactance stage) which replaces the variable capacitor to tune the fixed oscillator like in the E-Standard by a potentiometer is also not simply controlled by the tuning pot in the emitter circuit, but the potentiometer is followed bu a unity gain op-amp as a buffer which drives again a current mirror to feed the reactance transistor. Third, the reactance stage as a virtual variable capacitance does not act in parallel on the full LC parallel resonant circuit like in the E-Standard, but only on a part, there are two inductors in series.

Posted: 9/12/2020 11:21:52 AM

From: Rockville, Maryland

Joined: 9/12/2020

Having played three of those magnificent beasts I am unimpressed. Tube amp and baffeledspeaker improves it.  How you play it makes the sound more than the waveform.

For that great sound -mel 9 and talking machine.

But you can waste your time doing what you desire so the only thing I can say about this is that it is affordable:

Mooer tone capture has a sample of an rca sweep, load it into the box and then play your theremin matching the sweep and see if you wasted time and money. If you want dynamic harmonics a distortion box can do that. I use the kmise crunch 22 bucks. I think the kmlise will do more for you.

If you get it to work let us know, then I might buy one and give it a shot

Good luck and happy theremining!


Posted: 9/12/2020 11:45:54 AM

From: Rockville, Maryland

Joined: 9/12/2020

"At that time, there was no other Theremin which could play in such a deep bass register down to 30Hz besides the rarely available Russian tVox tour theremin."

Harrison Instruments theremins have a rich deep bass that goes down to sub audio.

Thierry, you are an expert, but until you get familiar with the easiest and best theremin, you have a rather large lacuna. There may be a model 302 still available.

Probably not for long - like the tvox.

I would have bought one . . .

Posted: 11/7/2020 3:37:05 PM

Joined: 11/7/2020

I got the Theremini instead of the Moog Etherwave mainly because of the price difference (maybe I'll get an Etherwave one day), but the 32 sound presets on the Theremini and the adjustable pitch correction are really sweet features that aren't present on the regular theremins. The delay is fun to noodle around with as well, but it is very basic and I'm planning on getting an actual delay pedal in the near future.

It takes about 45 seconds to set it up once you take it out of the box. Super easy and straightforward calibration. The onboard speaker gets plenty loud enough for private practice and just messing around, but I did plug into a Peavey 1x12 bass combo amp and almost blew my apartment windows out with the amp volume barely at a 2. All the pitches in the lower octaves especially sound really REALLY good through an amp. Can't wait to take it to a practice space and really let loose!

It's kind of a "point and shoot" instrument in my humble opinion. Sure there's classical playing techniques and hand gestures you can look up on YouTube to show you how to "properly" play the Theremini, but honestly after a couple hours of trial and error practice I found I could follow along with some slow songs and play the vocal melodies just fine. I cannot stress how much fun it is to play. I'll probably learn the finer techniques eventually, but for now I'm just having fun making sonic weirdness.

Summed up, it's just a nicely built, super light (3lbs), portable, crazy fun instrument that not too many people own. Unique and weird and absolutely worth the price. It was on backorder when I tried to purchase it originally, but my sales engineer Ashton helped me get a pre-order ready and called me the day they were restocked. It was in my apartment 3 days later! Great service as always from the crew at Sweetwater. Fast and reliable.

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