Hoag Instruments has announced that the intellectual property rights for its optical pickup technology is for sale or available for possible licensing.
This is Ron Hoag's 1970 circuit, which is very simple and inexpensive to make. The new design has LEDs, not light bulbs. The circuit and sound are the same (sound clips are available at www.opticalguitars.com). Companies may adapt the case style to their own instruments.
The inductor is high impedance and will develop the 'magnetic snap' that magnetic pickups give as the coil discharges. The circuit that follows the capacitor 94 is representative of the audio amplifier.
The pickup circuit has no active devices other than the photo devices. The output voltage is controlled by the amount of light radiation from the LEDs--the more radiation, the more voltage output. This circuit has 3 to 5 volts output. Higher output can be obtained and can reach up to 30 volts. New amplifier designs can take advantage of this higher voltage.
Interested parties may contact Ron Hoag directly:
P.O. Box 3053
Newburg, OR 97132