Connecting Etherwave problems

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.

Rob.

One more thing.....

Keep as much physical space as possible between the Moog and anything digital.

They generate RF noise that could mess with the Etherwave.

Thank you for your answer. It makes a lot of sense. My best solution today is to mic the cube. But the best thing would be to direct connect the etherwave to my zoom or a computer. Is there any inexpensive filter solutions?

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.

Looks like Jason posted at the same time as me.

A direct box is similar to the two transformer circuit and should work quite well. I forgot about them.

Old age...Sigh.

Thanks a lot w0ttm and Jason. Hopefully I will soon be recording my theremin.

Will this do?

http://www.thomann.de/gb/millenium_die_dibox_passiv.htm

or should I put my money on something more like this?

http://www.thomann.de/gb/millenium_dip_passive_di_box.htm

There is also the the active version:

http://www.thomann.de/gb/millenium_dia_active_di_box.htm

I think the first one would do.  I use a passive one with no problems.  I'm not actually sure what the benefit of active version is - anyone know?  To me, it's just another battery to change :)