Volume Control Problem

Posted: 11/2/2008 9:48:12 PM

Joined: 11/2/2008

I recently hooked up my Etherwave Standard and attempted to tune it, however I found that my Volume loop is entirely unresponsive unless I am touching it. When I touch it, it drops the pitch a little, but does nothing for the volume. It worked last time I tried it, a few months ago. What am I doing wrong? Is it a problem with the theremin itself?
Posted: 11/3/2008 3:09:05 AM

From: Colmar, France

Joined: 12/31/2007

Try to tune the volume circuit as described here (http://www.moogmusic.com/manuals/HotRodEtherwav.pdf) starting on page 7. Verifying the indicated VCA voltage with a voltmeter when tuning L11 will help us in diagnostics.
Case a) The voltage on pin 12 of U3 behaves correctly after tuning L11 and the volume circuit works - you are done.
Case b) The voltage on pin 12 of U3 behaves correctly after tuning L11 and the volume circuit doesn't work - we will have a nearer look on the VCA and waveshaping circuitry.
Case c) You cannot tune L11 so that you get the desired voltage behaviour - we will verify the volume oscillator circuit.

Keep us updated so that we may help you with further steps if needed.

N.B. If you aren't familiar with a voltmeter, you could look after someone in your neighborhood who can help you with this. Or tell us where you live, so that an other TW member could look after your Etherwave.
Posted: 11/3/2008 5:32:00 PM

Joined: 11/2/2008

Thank you. I will try this as soon as I am not bogged down by homework. I appreciate the advice. My physics teacher will be able to help with the circuitry.
Once again, Thank you.

Posted: 11/7/2008 10:20:10 AM
Thomas Grillo

From: Jackson Mississippi

Joined: 8/13/2006

When tuning internally, don't forget to place the cover back on for testing, as this will affect tuning.

You don't have to undo the connections, or re insert screws. You can test with the cover flipped upsidedown, and just resting over the circuit board.

Otherwise, you will get it tuned without the cover, and then have to retune when the cover is back on. That can get annoying after a fashion.

I have a seperate cover with pre-drilled holes for accessing the lugs. I use this cover when tuning my other etherwave standards.

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