First I would like to thank everyone on this forum. This is a great place to get started with the theremin.
I am having problem connecting my etherwave and getting a nice sound. For the moment I am using a Roland Cube CM-30 and getting the sound I want. But when I connect it to my Zoom R24 to record it suddenly sounds distorted with a lot of interferance. The same problem running the signal through a kaossilator. What am I doing wrong?
Wild guess here.
I think you might be getting a bit of HF past the filters in your Moog. That can play havoc with digital equipment, including computer sound cards.
There might be a malfunction in your Etherwave, but I'm not sure how much HF bleed is normal for this instrument. Analog amplifiers, like your Rolland would be unfazed by this due to limited bandwidth.
Low pass filtering of anything above 40 khz should fix it.
If all else fails mic the cube or use it's line outputs if it has them.
You might try using a direct box to drop the signal strength down by 10-20db. A theremin has more of a keyboard-like power level to its output than a guitar, which I imagine the Zoom is intended to be used with. You can usually find these in the $20 price range at music stores.
Sadly, I'm aware of none available for these frequency's.
Building your own is he best option I know of. The connectors and case will cost more than the parts in a simple filter like this one.
The values in this circuit are just starting points. The larger the caps and resistor, the more HF rejection, but it will also start to cut the treble if you go too big.
Play with the values a bit until you get a decent compromise.
Another that might work is made with a pair of Radio Shack miniature transformers wired back to back. Don't connect the input and output shields together for best isolation.
Placing ferrite beads on the leads should help as well.
There are active filter circuits that will work much better than these. If the simple ones don't cut it, we can go that route.
Will this do?
or should I put my money on something more like this?
There is also the the active version: