Audio Signal Controlled Lighting
SCR-based audio-signal-controlled lighting circuit
Ovation Freq-Lite
115V AC supply; output 15V-150V DC lighting load (max 150W)
1970s
US
19 components
Ovation Freq-Lite schematic: an SCR-controlled lighting circuit that modulates lamp brightness in response to an audio signal from a speaker/amplifier tap. Features a transformer-coupled input, bridge rectifier, RC filtering, trigger diode firing circuit, and an RCA-2N3528 SCR driving a DC lighting load up to 150 watts. Includes sensitivity control (R-5) and background light level potentiometer with on-off switch (R-4).
Components
T-1 Audiophonics transformer #S316S01 EX-737-A
R-1 33K 2W resistor
R-2 10K 1/2W resistor
R-3 10K 2W resistor
R-4 250K potentiometer w/switch 2W (background light control & on-off)
R-5 1K 2W resistor (sensitivity control)
R-6 33K 2W resistor
C-1 0.068uF 250V capacitor
C-2 0.01uF 250V capacitor
C-3 0.15uF 250V capacitor
C-4 0.001uF 600V disc capacitor
D-1 1N4003 diode
D-2 1N4003 diode
D-3 TI-42 trigger diode
D-4 1N4003 diode
SCR-1 RCA-2N3528 SCR (do not substitute)
F-1 2 AMP fuse
NE2H neon lamp
Bridge rectifier 1/4 AMP diodes (4 places) 125 VAC