best sounding theremin to build?

Posted: 1/4/2010 12:55:52 PM
jeremypb

Joined: 12/29/2009

i'm building a theremin for my brother and was wondering everyone's opinion of the best sounding one with relatively easy playability (that obviously have schematics available).

i don't want to buy a kit. and i don't want it to get too expensive, luckily i have most standard parts already.

i'd appreciate any suggestions. thanks.
Posted: 1/7/2010 2:44:54 AM
FredM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007

There are LOTS of different (sometimes heated ) opinions about the "best" sound.. my advice (from a technical perspective mainly) is..

1.) Think about Linearity first! Even if the tone is lovely, it is of no use when the Theremin is unplayable!

2.) Listen to the sounds of different Theremins.. Lots of you-tube.

3.) There are a few 'main' groups.. (a) Those (like the EW Standard) which have deliberate distortion applied, and/or start with waveforms having high harmonic content. (b) Those (few) like EW-Pro which have waveform modification / filtering mainly on the audio side, and allow a wide range of timbre control. (c) Those which have more sine-like 'starting' waveforms and 'cleaner' distortions applied to alter the timbre.. These include the Enkelaar ,Jaycar, Silicon chip, EPE Theremins.

For a low cost Theremin with good linearity and reasonable control over timbre, I do not think one can beat the EPE 2008 Design - This is in the 'c' class - To my ears, the tone is sweet and smooth, and can be adjusted just enough to add 'richer' harmonic tones.. But it will never be as grungy as the EW-Standard's maximum distortion settings... Likewise, I do not think the EW can produce such a pure tone as the EPE - particularly at the Bass end.

I have built several of these Theremins, and modified them for use as a test platform for other Theremin developments I am doing.. My notes can be found here:
Theremin General Resources on E14 (http://www.element-14.com/community/groups/theremin-general-resources)
(This site also has schematics etc for other Theremins, including the Moog EW)
(.. PLEASE .. If you find any other interesting Theremin designs in your research, post a copy on Theremin General Resources on E14 (http://www.element-14.com/community/groups/theremin-general-resources) .. I would like to get as many resources here as possible!)

This is an annotated schematic / layout with some added test / expansion points shown:
EPE Schematic (http://www.element-14.com/community/docs/DOC-16872)
This particular Theremin [May/June 2008 EPE] is, in my opinion, by far the best of the EPE / Jaycar family.. the EQ coil when correctly tuned with the antenna, gives good linearity - The Optical VCA is clean and does not introduce distortion which one gets on some earlier and later Jaycar / EPE Theremins which combine the mixer and VCA.. Also, it is possible to add "Preview" to this Theremin, but impossible to do so on the other Theremins due to mixer/VCA being combined. I rate this Theremin highly.

You can buy a PCB from EPE (http://www.epemag.wimborne.co.uk/acatalog/May_2008.html) (UK) and I advise this.. But the PCB can have a track fault (easily fixed) details on fault and fix given here.
PCB Bug (http://www.element-14.com/community/docs/DOC-16873)

If you go this route, I can supply you with Transformers, EQ inductor, and Opto Isolator if you donate >= £10 to Street kids rescue (http://www.streetkidsrescue.org)

<---- My email (see picture)

Posted: 1/14/2012 6:04:24 PM
motorbongo

From: NL

Joined: 1/14/2012

Hello,

 

My first post here, great overview, much appreciated! It's been ages ago that I built the simple theremin (EPE'95) but just recently started to use it live.

Must admit it's mainly for live-soundtrack-FX, but I do like the sound. Was wondering in which sound-category a/b/c this one would fall?

 

Now the DIY-bug pops up again so was thinking about building another, in bigger case and keep some room for eventual expansions.

Reading the above, the EPE2008 sure looks interesting, good to hear.

I was wondering, how does the next EPE (from March 2011) compare ? It's presented as being simpler yet better sounding. I'm curious to the opinions & experiences of the people here.

Both the 2008 & 2011 PCBs seem still available from the EPE PCB Service, so going either route would be possible.

 

Thanks & have a good weekend,

  Peter

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