These are the BASIC parts used for both Pitch & Volume Control
At first we will have a Pitch Only board with a whistle out at Out-2B

There is enough info on this graphic to stuff the step #1 basic parts used for both Pitch or Volume Control

The Antenna starts at the PCB, use a 6" to 18" temporary stiff wire antenna for testing. Retuning is necessary with antenna changes.

I am using the Ant2 connection currently for the antenna.

Do Not snap apart the 3 x 3 section, it is much more practical to build and use the board as one piece.

Leave off  R25-470R on both volume and pitch boards. The transistors I now use needs more range for tuning.

The RF mixing diode D2 on the 3 x 3 section is forward biased through Pot-5-100K and the R24-1 Meg resistor.

The parts displayed as a skeleton graphic are also installed. Note the 8 jumper wires installed, do before testing the boards.

The two boards can only be tested with Pot-4 installed or mount a Terminal here for a remotely mounted Pot, this can use a twisted pair of wires up to 10' away. For testing place a 470 ohm resistor across the terminal. Do not mount R25.

Unless otherwise stated, the parts on the pcb that have a line through them are not installed unless stated elsewhere.

Special Notes: 

See Modifications, use the purple wire to send the Output-1 signal to Out-2B on the Volume board. Only use the three end TRS jacks.

Mount R7 - 470R with 1/4" wire up from board on the side facing toward Out-2B. This makes for an excellent test clip point.

Mount C10 - 470 uf with 1/2" long leads above the board so it can be moved out of the way of J2 plug passing by.

The TLO82 & TLC555 work fine, today I prefer swapping in the LM358 & NE555.   Mount IC sockets!

Under board ground plate PDF. This is under the fixed Pitch oscillator only side for wave shape, also can extend under U1 to shield against noise. Do not have under under L2.  This is not used on the Volume control board.

Stuff the 3 x 3 section left side of boards first.
2 hour total construction time for the two 3 x 3 sections.  
The complete electronic build could be done 8 hours.

Mount the board stand-offs.  Always stuff the resistors with the gold band on the right side.

For the RF oscillators use MPS-A42 transistors, by experiment these work the best!

Separate out the parts used for the 3 x 3 osc board.  T1 x 3, Ant and HE-1 are six terminal blocks total.  

Below is both boards:

Mount these first to avoid confusion  C7, C8 = 100pf  -  C2 & C5 & C18, C20 & C27 = .1uf 

C13, C16, C22, C23 = 47pf  

R8 & R20 = 4.7k  yellow, violet, red, gold (emitter resistor)   R9 = 100k  brown, black, yellow, gold

R5, R6, R15 & R19 = 10k brown, black, orange, gold

R23 = 220k  red, red, black, orange,   brown = 2%

R7-1K  was changed to R7-470 ohms, this allow a louder volume no hand near the loop.

R12-1Meg was changed to 47K for less gain.

A terminal can be placed at Pot-4 so twisted wires can connect to a remotely mounted tuning Pot-4 up to 10' away.

Pot-4 - 1K used for tuning for the Null point.

View the 3 x 3 Stuffed Parts  for Testing and Heterodyning.  Do this test after stuffing the 3 x 3 osc section, it is exciting!

Parts below are on 5.2 x 3 board section  (Right half of board)

Mount the IC Sockets

C2, C5 = .1 uf  The jacks may get in the way so mount these two first.    C10 = 470 uf 

R21 = 470 ohms @ 1/2 watt both boards, this adds a little extra load to the 7809 voltage regulator.

Pot-1 10k and Pot-2  1k are on board trimmers used on the Pitch & Volume boards adjusted to 1/2 CW at first.

Mount the three TRS stereo jacks. A dimple should be drilled just above the #1  View TRS info here

Jumper Wires - Their are 8 total per board. The +9v wire has a modification that is highly recommended for the Pitch board only for better power supply filtering (R31 & C29) for the RF oscillators which will create the cleanest sound.

Don't forget to add the three jumper wires at the score to connect the 3 x 3 & 5.2 x 3 sections.

The 7809 metal side faces away from the board. This should never be hot, set your wall-wart on 9v instead of 12v and check if the theremin still works properly. The theremin load is so low the wall-wart might operate higher in voltage.

Verify the LED polarity direction before mounting, use a 1K resistor inline with a 9 volt battery.

Power a single board with 12 volts at terminal T6 and pass this +V to the other basic board using a TRS stereo cable from J2 to J2 on the other board. The theremin tone does not pass from the J2-Jack to the other board yet, just power. 

The Red LED should briefly flash it they are mounted correctly. When tuned the Red LED will glow when an audio signal is heard even above human hearing. This makes it great for visual tuning once you see how this works.

The theremin pitch audio tone should be found at Out-2B TRS Jack "after" you complete this webpage.

Visit custom mods & needed wiring for the transformer and passing the audio signal through the J2-jack.

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