Easily Protect the EtherWave Standard from Static Discharge

Posted: 9/10/2018 4:57:26 PM
oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

Buggin's thank you for the interest!

This method does work perfect , I found static discharge or ESD to be in the range of 8 kv to 15 kv, below is a very good remedy to avoid damage from this issue. Using the HV wire does not change the volume tuning or response, both remain the same as before the modification.

This method bleeds off the static charge into the atmosphere and it also eliminates the issue some theremins have from grabbing the volume loop.

Christopher
http://Hwy79.com

Edit: The HV hot wire to chrome loop capacitance is ~3 pf, your original good volume sensitivity and tuning remain unaffected. The metal loop doesn't behave as a capacitor unless it is touched? A static discharge is dissipated about the loop, not through your circuit.

Posted: 9/10/2018 8:03:04 PM
Buggins

From: Theremin Motherland

Joined: 3/16/2017

Thank you!

Didn't you try to do the same trick with pitch antenna?
Of course, pitch antenna is being touched not as often as volume antenna, but it's important to protect it, too.

Posted: 9/11/2018 12:34:08 AM
oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014


Buggins said: Didn't you try to do the same trick with pitch antenna?

Often I would add a clear plastic sleeve or pipe around my pitch antenna coil but this was more for support.

When I began my theremin journey all my designs are original because I never looked at how any other theremin was designed. Someone would only do it this way if you are really stubborn. Coming from an amateur radio background WD6EDZ it was obvious to me RF heterodyning was involved.

I found a perfectly linear pitch field early on by tuning the LC tank circuit to a coiled pitch antenna. Available are five linear octaves from the outside field right up to the pitch coil at any width of the field. There are no almost linear octaves, they just snap into position. Others talked proudly of their 10 octaves so did not give much thought to my linear five.

Below demonstrates how a theremin design can be very simple while responsive if you have specific knowledge. This design has a perfectly linear pitch field without inline special inductors, is thermal drift free using 300v MPSA42 bipolar transistors which also enhance the sound using a Hartley oscillator configuration operating on a single supply of 9 volts . This same circuit but with a loop is used on the volume side but with a 555 added to get an ideal PWM volume control capitalizing on the pulling of the RF oscillator wave shape over the 18" distance of the volume control window.

Simple Sound from a simple design

Beautiful "natural" sound unique to a theremin comes from re-shaping a sine wave through its range, even Clara's voice. This is more difficult to do than using a simple equalizer. Never should a theremin sound like a child's toy keyboard mixing different noises and filters to get beeps and whistles, that would be a gesture controller.

Christopher
http://Hwy79.com


Posted: 9/11/2018 6:22:54 AM
Buggins

From: Theremin Motherland

Joined: 3/16/2017

Sounds very warm, especially with vibrato.

Posted: 9/18/2018 7:00:54 AM
Buggins

From: Theremin Motherland

Joined: 3/16/2017

I've ordered 40KV cable, so I'll test how this method works for both volume and pitch antennas.

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