This is a light controlled square-wave generator with a pulsing effect, hand built into an Atari paddle controller. These were originally built by Gemini for the Atari system. Pitch is controlled by a light sensor, speed is controlled by the knob, and the trigger is power. At high speeds you can get some interesting throaty sounds. For more precise control and wider pitch range experiment with different light sources.
A red LED pulses with the sound. It can easily be connect to amps, effects, recording equipment, etc. At the end of the original cord is a 1/4" plug and running from there is a wall adapter for power.
Housed in an early surround sound mixer made by Victor, this synthesizer is based on the stepped tone generator designed by Forest Mims, also known as the atari punk console.
X (up and down) controls the frequency and Y (left and right) controls the pulse length. The original volume control is used. The large white button (also salvaged) is power and lights up when on. It runs off an included internal 9v battery and a standard 1/4" inch jack makes it perfect for connecting to amps, effects, or recording equipment.
This is a five key square-wave synthesizer with sweeping LFO (low frequency oscillator) modulation. There is a frequency control that sets the range of pitches laid out on the buttons, so it does not play specific traditional notes. It is monophonic and will sound the highest pitch being played.
The sweeping LFO modulator can be turned on or off with a second switch and has a control for speed. A green LED pulsates in time. This is an analog circuit and often makes a slight click when it sits idle at low speeds. Also the effect lowers the volume slightly but can easily be adjusted with the volume control.
There is a power on/off switch with a green LED and a standard 1/4" output. Power is supplied by wall adapter.