I have a Burns "Great Sounding" theremin. It has one antenna for pitch control. I am using a Honeytone mini amp. I would like to add a Yamaha foot pedal for volume control. The foot pedal is something I already have with my electric keyboard, so I was hoping to use it. It has a 1/4" jack. Has anyone done this? I know I need to add the foot pedal between the theremin and the amp, but what should I buy to make the connection?
Thanks!
I think you need to determine if you just have an expression pedal or a true volume pedal. Likely its just an expression pedal. You would need to put some controller between the theremin and the pedal in this case - not worth it. Though the engineers here will have ways to make something from a cheap pedal I'm sure - but I don't know if you want to go down that road.
Go online and search for passive volume pedals. But these are normally geared for guitar impedance. It's not clear a theremin will sound as good with some of them. An active volume pedal (needs power) may be what is going to do the best job - but that's like putting a little amplifier between your theremin and your amp. May not be cost effective.
http://missionengineering.com/?page_id=738
http://missionengineering.com/?page_id=4029
Rich
twylla said: "The foot pedal is something I already have with my electric keyboard, so I was hoping to use it. It has a 1/4" jack."
What you want to do makes for a good experiment. It will lack the fluidness required for theremin play. What is the Model # of the Yamaha pedal, there are several types. I was trying to encourage Valpoder here at TW to design exactly what you need.
Your theremin needs an earth ground for better sound and response. This is normally obtained through an amplifier with a three prong plug. A wall-wart or battery will not work effectively.
Are you in So. California?
Christopher 
I am in Kansas City MO. The foot pedal is for a PS-6100 Yamaha Electric keyboard (from the 1970's). I don't see a specific model number on the pedal. I ordered a $5.00 adapter with one 1/4" male connector and two 1/4" female connectors. I am going to try to plug in the pedal and the theremin to the amp with this adapter. I am thinking it won't work, but I thought it would be worth a try. Thanks for all of the information. It sounds like it would be most cost effective to upgrade to a theremin with pitch AND volume control. Thanks again.
If the Yamaha pedal has TWO 1/4" jacks (labeled IN and OUT) it may work. If it has ONE jack (per original post) it will not work. A quick google of "burns theremin with volume pedal" coughed up someone claiming to use an Ernie Ball VP JR pedal, which is just a regular old passive 250K ohm pedal. I think it is insane that ANY passive volume pedal costs more than $50. There is no magic here. It is just a dumb old pot actuated by a rocking pedal.
You probably wont get the tone suck that some guitars players claim to find by driving the output of an passive inductive pickup into an extra parallel resistance in their signal path. The Burns output is its own buffer, and it doesn't suffer line and load losses like a magnet with a few wraps of wire around it (guitar pickup). It can squirt some juice down the hose with some pressure. 500k or 250K ohms don't choke the Burns none.
Of course, since you don't have a volume antenna, you got one hand not-being-used...
It doesn't need to be a stupidly expensive pedal. It doesn't need to be a pedal at all. One could easily cobble together a box, two 1/4" TS jacks, a pot, and a big honkin' knob, and control the volume with your volume hand.
I have used several Theremins with a passive 100k volume pedal with no loss of tone due to Impedance Mismatch (the output stage design would need to be impossibly bad), but...
Standing on one leg, operating the Volume Pedal destabilises me so much that Pitch Control becomes impossible.
"Of course, since you don't have a volume antenna, you got one hand not-being-used..." is a far better idea.
I STILL use a Volume pedal, but only to make sure the Theremin (and other non-guitar gear) is silent when I'm not playing it and to tame a too-loud setup without making a trip to my amplifier.
chainsaw wrote: "...big honkin' knob..." godhowilovethatstuff! absolutely true.
twylla, you're a tinkerer or one that knows a bit soldering? even if you know only wich side of the iron get's hot, you're in! it's a easy one really...IF your volume pedal has a tip/ring/sleeve, TRS-jack, it's quite possible to tinker a volume pedal for external things...tip/ring is in or out and sleeve is ground.: measuring the resistance, when pressing the pedal, between sleeve to tip and between sleeve to ring, should give you the clue. the one value that changes is usually the output. (the whiper of the pot inside) but it will work both ways. the measured value that does not change gives you the pots resistance. (the two outer lugs of the pot.)
take two mono female jacks for in and out and a stereo female jack for the pedal. connect all 3 sleeves (for good ground) together. then from the stereojack tip to a monojack tip and from the stereojack ring to the other monojack tip. that's it, i guess. (of course you need also a tin small box just big enough to get the jacks mounted inside.)
but if you're a tinkerer, you already know that there are many other nice ways to control the volume. it's mostly pure resistance.
a bigger better, grounded amp might be a point to invest some money? honeybunnybuzzeebee is too small
xtheremin8 said: "but if you're a tinkerer, you already know that there are many other nice ways to control the volume. it's mostly pure resistance."
Agree, adapt a CdS cell or light dependent resistor in the hacked cable.
My favorite simple method is an optical volume control, a finger controls with good shading.
This Sample.mp3 I am controlling a Radio Output to amplifier. A theremin is basically the same setup.
I have been doing an update to my Optical design with a new Optical Theremin II because most Googlers use the key words, want something "simple & cheap". This has a much better sound than a Theremini.
twylla, if I had pcb's made I would have sent you one at no cost but that is a ways off. My new Optical design has multiple configurations and applications yet to be explained.
Christopher
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