Note: Assemble your circuit board using the ironed on component patterns
           and the notes below as reference.

           Get the board operating before switching to any panel mounted Pots!

The Lev Antenna

For the Lev's Antenna instructions that you give, I have the ferrite rod and the variable capacitor from a cheap radio, do I just hook them all up in line -- "Ant" on the pc board to the variable capacitor to the ferrite rod to the spring?

You are correct. View this Schematic

I can get the weird swooshing sound on the am radio when tuning to the L1 and L2, so I guess I am headed in the right direction.

Hearing the swoosh from each oscillator is excellent. You must now move their frequencies one on top of the other to hear the theremin pitch/whistle. Read the Tuning Webpage

L1 Choke Coils & L2 Coil Homemade

Note: Orientation of the L2 coil is critical. On the board the coil metal side must face towards LED 2. The coil metal side is A4, A3 is 60 wire turns from the metal side and the open end is A1.

Do I only need to wind one coil now because of the RF Choke coils?

You are correct, this makes the construction more solid.

Mount the two 100uh L1 choke coils with 3/4" clearance above the circuit board.

Well, I went ahead and made the coil with the bigger salt container, and right now my AM radio is whistling at me. And I had to remove quite a few coils to tune the oscillators together, so I guess that was because it was wider. I only needed about 65 turns, instead of 80. But I tuned them together and got sound by waving my hand around by the L2, so I'm very excited.

This coil calculator might have helped with your modified coil:

Coil Calculator   (this is not needed when following my coil making directions)

Extra L2 coil wraps of wire are easier to remove than adding some! lol

Ideally the air core coil like L2 should have its total length of "side by side" turns match the diameter. You have enlarged the diameter which does work so continue on and explore.

When the Lev Antenna is mounted and connected it will behave as if adding more wire turns onto the L1 side coil chokes. This is why my kludge ferrite choke rod is inserted in the air core L2 coil, this will offset the difference.

Mounting the Parts

RS Illusion Parts List

Panel Mounted Controls

Mount the two 100uh L1 choke coils with 3/4" clearance above the circuit board.

S2 - If you switch LED 2 on or off it can have different effect on the sound when the Audio-Out is controlled through the CdS volume sensor into an amplifier. The switch pads are normally connected together on the copper clad side of the board, "do not drill" the pads apart unless you add a switch. 

C20 - 4.7uf capacitor (Audio Out) is Non Polarized. Mount it standing on end, either side up.

LED 1 & LED 2
The fat lead inside the clear plastic LED is the positive side or anode. Solder this to the + plus side indicated on the pc board. This works for the Radio Shack LED but is not always the case. 
Read the package your part came in for proper polarity and direction.

These Radio Shack # 276-307 LED's have a 12 degree projection angle and throw a 3000 mcd  beam out
2 feet (1 meter) Other LED Colors have higher operating voltages and don't work effectively.

I can't for the life of me figure out what the 2-position PC Board terminals are for. The list says optional, but where do I put them if I have them?

You solder them into the terminal pads indicated as square boxes on the board silkscreen. This gives you easily removable wire connections. They are blue on the circuit board photo below.

Put a little solder on the "wire tips" inserted into these terminals to fatten the tips up bit, then insert the wire into these circuit board terminals and tighten the set screw.

I know your FAQ says that you do not have a picture of the completed board to display, but if you ever have one available, a picture would be extremely appreciated.

Board Photo  Visit this link

There seem to be extra holes in all of the potentiometer areas. Do I put the pots in the straight line of holes, or some different combination?

The potentiometer has three individual legs. The three individual pads on the board have extra hole combinations for those that don't have available the Radio Shack pots. Hold your potentiometer legs to the foil side of the board to determine which single hole in each pad should be drilled for the best mounting. Each leg of the pot must be on it's own separate pad.

The component list says I need only 4  .1uF capacitors, but there are 5 listed.

C13 - .1uf is not shown on the schematic has connection pads on the pc board. This part would only be used if you separated the RT pads to use the R-Tune remote null adjuster. I have not used this yet. Normally the pads are tied together on the foil side of the board.

Ignore the white line between the two terminals on Pot 3. A jumper wire only goes here if Pot 3 is not mounted on the board for a minimum theremin construction.

Audio Out

How do I add a Pitch Preview to the RS Illusion?

Use the Output terminal + pad to the left side of LED 1 and replace the R8 -100 ohm resistor with a 4.7 uf non-polarized electrolytic capacitor. Use headphones that have an inline volume control on the cord. This wire connection should be through the tip connection on a three wire stereo jack; while the normal Audio Out to the CdS volume sensor is from the middle plug connection. Wire your headphone jack at the remote volume stand where the CdS sensor is located to keep the headphone wire from interfering with the pitch electro-magnetic field. This also allows for the shorter headphone cable.


Is the volume circuit necessary for it to work? 

My volume control methods are external add on components and does not need to be made or used for basic theremin effect demonstrations.

For the Audio Output, once I've attached the CdS photocell do I just hook it straight up to a speaker?

The CdS photocell output could drive a pair of amplified computer speakers directly with the theremin Audio Out Pot 2 turned fully clockwise.

The CdS photocell output could connect to the microphone level input of your computer. Turn down Pot 2 a bit. This allows for wave file capturing using something like Audacity and using the Pitch Tuner program. The C20-4.7uf non-polarized capacitor creates needed DC voltage isolation between the output to the mic input.

Note: Do "not" hook up the volume control method until you have everything working. Connect the RS Theremin board "Audio Out" directly to amplified speakers or the computer microphone  input. 

Turn down Pot 2 a bit for microphone inputs on amplifiers.

Currently I am designing a small volume control circuit board so the CdS sensor will have output pre-amplification to drive the input of any amplifier from mic level to line level. Also the Pitch Preview will be taken from this circuit board with a panel mounted volume control. On the RS Illusion circuit board the big square pads at R10 are where the battery power will come from. This would be one of the three connections using a stereo jack, the other two connections would be the Audio Out and Ground.

Unusual Silkscreen Markings

R8 - Not shown on the schematic is used to connect to the Ultermen Output terminal. (not used)

R10 - This resistor on the board near the RS Illusion words is not currently used .

C13 - .1uf is not shown on the schematic but has pads on the pc board. This is only
           used if you separated the RT pads to use the remote null adjuster. Thanks Emerson K

C20 - 4.7uf capacitor (Audio Out) is Non Polarized. Mount it standing on end, either side up.
Electrolytic capacitors "must" have their negative - side away from the plus + on the circuit board.

There are two squares on the silkscreen, labeled "sqr" and "gd", in the middle of the board, just below the TLC555, that I am unsure of their function. What do I put there?

This is a experimental connection for something in the future. You will not be using it. It uses a raised ground level that can trip up the TLC555 from operating if not isolated from the main ground when used.

The Photo Showcase

Once I'm finished with the whole thing I'll take lots of  pictures and descriptions that you can put in the gallery.

That would be great. I have an old program I use to organize and place each picture on its own unique webpage from a thumbnail click.

Showcase - A gallery of RS Theremin builder construction photos.

The Sound

Visit Diagnosing the Sound of Illusion

And, I think that most of the sound bytes are very nice. I really like the "Clara" ones, and I absolutely love the polyphonic theremin one you did, song8.mp3  is the link to it.

This sound comes from using my Ultermen 5 polyphonic octave divider board. The Ult-5 outputs different square wave octaves on five separate modulated light beams. I pick up the beams with a hand held solar cell. This solar cell then feeds the now softened square wave into a one watt amplifier driving a speaker inside of a large metal bucket! lol

A microphone plugged into my computer, placed within the bucket, records the sound . Any time I use acoustic enhancements it tends to get very frustrating. )-;

Integrated Circuits: U2 & U4 Both IC's have a notch on one side of their package. This notch or the dimple in one corner must face away from the L2 coil you made. The dimple is just above Pin #1 in the corner. This pin must solder at the location Pin #1 as indicated on the silkscreen.
Transistors: Q1 & Q2 The transistors have a half moon shape. Both transistors mount in the same direction with the flat side facing the L2 coil you made.
Diodes: D1, D2, D3, D4, D5, D6, D7 Diodes usually have a black line on one side of it's body. This is the negative side. The line also represents the line opposite the arrow when viewing a schematic.

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