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4.26.14 

Theremin
Pitch Popper

Pop On - or - Pop Off
Theremin Musical Notes
Inception April 15, 2014

Aggressive Theremin Volume
Authentic-Tube.mp3 
* * *

  Page is Under Development

RS Theremin
www.Hwy79.com

by Christopher


The heart of the Popper is the 
basic 555 switch de-bouncer.

Attack "with-out" Black Tube
 Listen.mp3
Radio Audio

Volume Attack mp3  350k
Popping the Sound "Off"
Theremin Audio

Listen.mp3  500k
Popping the Sound "On"
Theremin Audio

Shading "with" Black Tube
Listen.mp3
Radio Audio
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This is all Natural Real Analog!   No Cheap Digital Whistles or any Latency

* This is the answer to making a Pitch Only Theremin more musical or Any Theremin for that matter *

Triggering the Volume Effect can be done with a CdS Cell, Photo-Transistor, FSR etc. 
As a foot pad it can be made as thin as 1/8" (3.175mm)

A friend of mine created a musical instrument that within just a few months, made the most recognizable theremin sound ever recorded, his name was Paul Tanner. He would spend the next 50 years listening to anal people saying "that's not a theremin" instead of giving him credit for bringing more awareness to the theremin instrument than anyone had before. Anal behavior is rampant in the theremin community, hope you don't miss the point... again!
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There is no agreement today, even in the theremin community of what characteristics should define a theremin. 

I say un-restrain it, let it be a blend of Vietnam's Dan Bau, the classic theremin, Paul's box, etc.

* For me it is about a unique natural "analog" sound with character, not a whistle buried in reverb *

My good friend from Saigon is the grandson of Master Cao Van Lau, who is recognized as the Father of Cai Luong music of Vietnam. Though his grandfather passed  on long ago, listen to the sound of another Master Dan Bau musician.  Visit YouTube  Do you recognize that the theremin has something in common?

Master Musician GordonC at Theremin World suggested the need of a theremin volume control with good Attack, that motivated the creation of this webpage. 

What does this graphic of popping the sound "Off" with Attack sound like? Volume Attack mp3  350k

Natural "analog" sound , not that cheap digital whistle shit two rambling engineers have stumbled over for years looking for cheap!

If you are using a volume loop normally, you could use the Popper without the CdS cell section. Set the Popper below the volume loop so your hand on the loop allows you to tap the red button to pop on a note. You could add a tapping extension made with a wood dowel to place some distance between the Popper and the loop.

Stand the Popper at the outside of the volume field for tapping off the sound for an abrupt preset duration. If you hold the button down the sound remains off.

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Pitch Popper PCB
3.4" x 2.8"

Two fingers become a unique theremin volume controller, still use the volume loop and have a new experience.


Features:

The Pitch Popper uses four basic circuits that most budding electronic hobbyist build when first starting out.

1. A 555 switch de-bouncer or one shot, this creates the clean musical note popping. The "On/Off" duration is adjustable.

2. The LM386 mini power amplifier can drive a small speaker or use with an earphone for a Pitch Preview.

3. A 10k potentiometer is on the board for quieting the line-level drive of a hot theremin output like the EtherWave Standard, now it can drive a guitar amplifier effectively with all of the special effects.

4. Optical Volume Control to be used with the pitch only theremin setup. It uses a CdS sensor that would mount on the outside of the enclosure about 1" over from the push button. Let your two fingers dance. I connect the CdS cell to the T4 Bypass terminal. The middle finger covers the CdS cell for darkness which quiets the sound and the pointer finger pops-on musical notes. These are staggered positions. This setup will evolve!

Note:  A white LED was found to work best though a green LED better matches the wavelength of the CdS cell, it is lit from wires connected at LED-3 on the main Popper Board to shine on the CdS cell for maximum response.


Terminals

The terminals have a v arrow which indicates the direction the open wire side should face. 

T1 This is where the battery power is connected, observe the proper polarity.

T2  The push-button is mounted through the enclosure and it's two wires go to T2, which is labeled Button Wires.

T3 This has some future applications but for now just add a terminal.

T4 The Vactrol is off when the power is off and it will not pass sound. You could attach a Bypass switch across T4 so you can leave your cables plugged in and still pass sound. 

Two 3.5mm TRS jacks are used, one is for the Pitch Preview. The other jack powers this new Pitch Popper from my Phoenix or Dragonfly through my specially designed J2 jack, which also transfers the audio. Input 1/4" jack would not be used.



Middle Finger Board here...

This image shows a small circuit board placed next to the Red Popper Button. In practice either method/finger can cutoff the theremin sound with much greater attack than a volume loop. This is mostly due to the little movement needed to achieve the result.

The CdS Cell/LED setup may be all the volume quieting attack most want. 

Pass a line level signal through the CdS cell, this could be wired up on a generic pcb board. The LED and Cell can be placed inside a 3/16" id, 1.3" long black piece of surgical tubing. This gives you better control over volume shading. This could mimic an actual volume loop sound perfectly. 

I prefer no rubber tube for the freedom it gives just tapping the sound off with a finger blocking the LED light.

You want to use a CdS Cell with a high off resistance, 1Meg ohm is typical. 
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More info on the Middle Finger board here...


Construction Notes:

This Pitch Popper will add a distinct enhancement to any theremin sound because "popping notes" just sounds good.

Use this template for enclosure drill hole locations.

No need to drill the three Pot holes, these can be pre-set before the box cover is screwed down.

The main holes to drill are for the Push Button, the two 1/4" jacks. Decide if the other possible hole add anything you want to use.

Switching the battery pack off  will Mute the Popper sound.

Battery Life:  In the musical note pop-on mode they will last your lifetime because the Vactrol does not use current. If the Pitch Preview is never used remove the LM386 from its socket to increase battery life.

C3 & C5 is are not mounted on the board.

Three jumper wires are used around Switch S1. If no Switch is available you could use two shortl jumper wires. The location of the two jumper wires on the switch indicate the side for Popping the musical notes On.

The longer lead on the LED's is the + plus side, be careful, mount in the proper direction. Leave the LED leads long so they reach through the holes drilled in the lid of the enclosure. give lead length

Drill holes in the enclosure using the template for precision. Three holes give screwdriver access for the Pot adjustment. 

Lay a copy of the etching PDF trimmed  to get the alignment to drill the LED holes in the enclosure box lid.


Parts not at Mouser: (Shop around in your location, be aware of the extra shipping & handling costs)

Vactrol VTL5C4
Allied Electronics
Push Button NC
Amazon
LM386
Amazon
PCB Copper Clad
Amazon
Mic Stand
Amazon
Mic Stand Clamp
Amazon
4 x AAA Holder
Amazon

Mouser Project List (Click Order Cart to gather all the parts, then click again to Order Cart.)   

PDF etch your own board ?
Not Available Yet
PDF Excel Part List
Similar to Below
PDF Box Holes Template
Not Available Yet

     

If you have interest in building let me know and I will send you some stuff at no cost  as your success is most important.

Contact Christopher

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