Modifying E Standard in New Cabinet - Adding Built-In Effects

Posted: 6/9/2009 9:17:28 AM
theremin_ohio

From: Chillicothe, Ohio USA

Joined: 1/29/2009

Hello,

I have very little technical experience. But I have a good friend who is very technically versed and would like to assist me in making some modifications to my Etherwave standard. I am first going to shop around for a unique casing at an antiques shop (a small lecturn or something along these lines), and we are both wondering if it is possible to directly wire into the signal flow an effects pot that bypasses the volume control using a switch (as on a guitar). I believe I am explaining this query properly(!). Of course I will drill as many holes into the new unit as are required. I am interested in adding reverb, delay, a harmonizer of some sort and/or wah. I am just thinking this option would be more portable and practical than a pedal board as whenever I go to switch on/off my Fender pitch pedal my whole body moves slightly thereby affecting my pitch. Any suggestions? This is not a school project of any kind, and I could not find any information in this forum. Perhaps I do not have the proper knowledge to know which terms to search but I did spend a good bit of time looking around. Thank you to all in advance.
Posted: 6/9/2009 8:07:55 PM
Joe Max

From: Oakland, California

Joined: 1/2/2009

I have very little technical experience. But I have a good friend who is very technically versed and would like to assist me in making some modifications to my Etherwave standard. I am first going to shop around for a unique casing at an antiques shop (a small lecturn or something along these lines), and we are both wondering if it is possible to directly wire into the signal flow an effects pot that bypasses the volume control using a switch (as on a guitar). I believe I am explaining this query properly(!).

I don't know about the Etherwave, but I was cautioned about doing a similar modification to a Burns B3. Dan Burns explained that the volume and pitch knobs are such an integral part of the circuit that changing their position or adding any switching or loop jacks would grossly affect the sensitivity of the circuit, perhaps beyond the range of any coil re-tuning. Analog radio circuits are very sensitive to the layout of the parts in the circuit itself. Often a lot of trial and error is needed to hit on a reliable layout to get it to work, and it's not always easy to hack a pre-built curcuit

I was told that the best way to put a new box around an old theremin is put the whole theremin, box and all, into the new "outer case", making holes in the surface to align with the knobs on the theremin and stick them through.

Simply extending the wires going to the antennas is not such a radical thing to do. You'd have to re-tune the coils, but it's not a big deal.

Keep in mind I'm talking about a B3, not an Etherwave, so it may be a whole different thing.

Of course I will drill as many holes into the new unit as are required. I am interested in adding reverb, delay, a harmonizer of some sort and/or wah.

You may run into the same kind of problem with building effects circuits into the same box as the theremin circuit. More electrical "stuff" within a foot or so of the antennas is going to effect the tuning and/or volume. I wish I could put my Korg NanoKeys unit right on top of my theremin case for performance, but it throws the tuning off the range of the tune knob.

I am just thinking this option would be more portable and practical than a pedal board as whenever I go to switch on/off my Fender pitch pedal my whole body moves slightly thereby affecting my pitch.

Well, if you put switches on your theremin case to control effects, you're going to have to move your hand to operate them, which will definitely affect your pitch. I use pedals, but I don't switch them much during the course of a song so I've never noticed a problem.

Any suggestions? This is not a school project of any kind, and I could not find any information in this forum. Perhaps I do not have the proper knowledge to know which terms to search but I did spend a good bit of time looking around. Thank you to all in advance.

Definitely try to get in contact with the technicians at Moog before making any modifications. They can at least tell you what's impossible and what's merely difficult!

You might be just as well off to purchase a PAIA Theremax, which is a kit designed to be mounted in a variety of cases. It's supposedly an easier design to hack. I'm helping a friend build one this summer, so I'll find out more.
Posted: 6/9/2009 8:29:48 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

Although you asked me that already via another channel, I'll answer here:

a) Even without adding any circuitry to your EStandard, its transplantation into another casing is difficult and requires lots of theremin specific experience. The linearity of the EStandard, although not perfect, is strongly dependend from the static capacitance between pitch rod and circuitry. That's why you'll find a slighly bent wire of specific length between circuit board and antenna, partly above a grounded foil, inside your theremin. Even the 8 big screws which hold only the cover together play an important role. You risk to tinker around for months until getting a similar linearity in another casing. These are effects which cannot be adjusted or corrected by tuning the oscillator coils. No problem for spooky sounds, but difficult for precision playing.

I'm not sure if I understood well the other part of your question. Do you really want to bypass the volume circuit? That would mean deactivating the volume loop... I see no musical sense in this.

I rather think that you wanted to insert some effects before the volume control.

A constructional property of the EStandard is that the volume circuit (VCA) is integrated with the waveshaping. So any effects in place before this circuitry would also interact with the waveform and brightness settings.

So in your place I would rather consider to connect whatever effect box only externally since there are no interesting points in the signal flow which would allow a meaningful plug-in. Only if the casing would be big enough (and all other problems as linearity solved), one could try to build in the "nude" circuit board of a multi effect pedal such as the Behringer Multifx FX100, but only after the "classic" audio out. But even this solution when built in would have the problem that you had to use your hands to enable/disable and adjust effects. But you do not have a free hand when playing theremin. So it seems to me that the external pedal is the best solution.
Posted: 6/9/2009 10:27:51 PM
theremin_ohio

From: Chillicothe, Ohio USA

Joined: 1/29/2009

Thank you both, Joe and Thierry. Thierry, after I sent you a message on FB I thought better of myself and realized this might make for a thought-provoking thread. I think I will start with a call to Moog, but not before hashing out some possible ideas, including specific parts required. As to the pitch question, I do not find myself wishing to change the sound/timbre mid-phrase, so a switch would be no problem forcme as I would have my left hand near the volume loop. However, it sounds like there are many other factors I will need to consider first. I will post any tips from Moog once I have talked to them.
Posted: 6/10/2009 3:55:19 AM
GordonC

From: Croxley Green, Hertfordshire, UK

Joined: 10/5/2005

As a less intrusive alternative, one of my if-I-ever-get-round-to-it ideas is to construct an open-backed-and-topped box with shelves for my etherwave to sit on, and to contain all my cables and gizmos. In proportion it would approximate the monolith from 2001, which seems appropriate for a space control instrument. You could tap into the theremin circuit where required through the underside of its enclosure.

(Did you mean you want to apply effects to the theremin audio signal before its amplitude is affected by the volume loop?)





(OT, and in response to your question on the now closed business card thread: How do they loathe me? Let me count the ways. Straw men with a diploma instead of a brain, pretenders qualified only in bluff and bluster, promoted above their incompetence, who view themselves through rose tinted glasses, who see my madness but not my method, whose fa├žade of self-confidence barely contains their inner turmoil, who think they know everything when everything they know is wrong, who perceive me as anarchist and usurper, who cannot laugh at their own fallibility. Small people inflated beyond their boot size. Of them I say, as Jake Thackray sang, Beware Of The Bull.)
Posted: 6/10/2009 6:30:06 AM
theremin_ohio

From: Chillicothe, Ohio USA

Joined: 1/29/2009

Gordon, yes, my thought is to have the effect applied prior to the amplitude is affected by the volume. Is this a good placement for effects should my design be logistically feasible? I will share this thread with my friend (pictured next to me in my new TW profile picture--we were unspeakably drunk and ecstatic) and let everyone know what happens. Think I might instead buy a separate kit to mess with. Hooray summer project!
Posted: 6/10/2009 11:05:45 AM
GordonC

From: Croxley Green, Hertfordshire, UK

Joined: 10/5/2005

Easy with an etherwave plus - use the pitch preview instead of the main audio out (perhaps - if pitch preview has the same timbre as audio out), and control the volume at the end of your effects chain with a VCA connected to the volume CV out, but probably not good. For some effects - for instance pitch shifting - it would make no difference whatsoever. Most effects which distort the wave form are volume dependant - the louder the sound, the greater the distortion - feeding them a signal with constant volume would limit their functionality.

Time based effects - delays and reverbs - would be [i]interesting[/i]. Here we need to differentiate between two sorts of silence - true silence, when the pitch hand is in the zero-beat zone, and silent notes (http://homepage1.nifty.com/iberia/score_gallery_schulhoff.htm), where the pitch hand is generating an audible frequency which is then muted by the volume hand. Mostly during a performance you play silent notes rather than true silence. With a delay in the place you suggest, when you raise the volume you would hear the echoes of all the silent notes you were playing a moment ago. (You would certainly need pitch preview to play in tune!)

A simple experiment would be to put an expression pedal (low impedance inline volume pedal) after your effects chain and try using that instead of the volume loop. If all you want is the ability to mute a long echo before it has finished fading away, then use the volume loop as usual and leave the expression pedal in the chain for just such a situation.

Posted: 6/11/2009 12:35:59 PM
theremin_ohio

From: Chillicothe, Ohio USA

Joined: 1/29/2009

Gordon, I may try routing my theremin through not only an expression pedal, but also an ART unit I own that certainly has loads of effects. I thought perhaps if it is not feasible to alter the guts of a theremin I would simply build an effects rack that could be placed in the zero beat zone so that when I am playing muted notes by approaching the volume loop I do not hear those echoes of which you speak. But that might make for an interesting effect in any case. I also have a Morley wah that I have tested out a couple of times but it needs a new adapter and the 9V battery casing is faulty. That's another DIY project for another day. :)
Posted: 6/11/2009 12:46:53 PM
GordonC

From: Croxley Green, Hertfordshire, UK

Joined: 10/5/2005

You were thinking of building a wah pedal into your theremin enclosure - at waist height?!

Are you also a contortionist?

:-0

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