Back in the 1970's these were popular for use in homes and the colored bulbs were typically place in a box with a sheet of "rippled/bubbled" Plastic in front to break up the light patterns. Some units gave very impressive light patterns.
Using an LM324, this circuit has 3 active filters for the Low, Medium and High frequencies. ** This allows for a Much better seperation beween the various frequency ranges than the simple Passive Filters as used on many Color Organs.
Setting it up:
Set the Master Level to about a 1/4 on position.
Trimpots are initally used to set the 3 filters to equal ranges so the lights all flash in about equil amounts of time.
The Master control, is usually a regular potentiometer, is than used to set for various volume levels. (I just used a trimpot on my proto for testing purposes.)
As Shown on the Schematic, Proper Rated FUSES are Highly Recommended. Except for the On-Board fuse that protects the IC Circuit, The ones protecting the Mosfets should be "Automotive Types", with a voltage rating of 32 Volts.
"T1" is for Isolation and signal boost. It can be almost any small audio transformer, used in reverse. The one stated here is reasonably priced and fits the board nicely. "T1" is Essential to "Isolate" the audio output from ground on Non-Grounded Audio Systems.
"RX", As Shown on the Circuit Board is a series resistor to the 8 Ohm Input. It may be Necessary to use an appropriate value resistor to limit the current to T1 if this is connected to a power amp.
In all my tests I went directly into T1, but I was running this circuit from a Headphone output, Very low power. I would suggest a value, somewhere between 50 to 500 ohms, depending on your input power.
Heatsinks May be required on the Mosfets, Depending on you load Currents. For the N-Mosfet Version, The RFP50N06 has a good rating. With a Proper Heatsink, it is Probably suitable for loads up to 30 amps.
The Two transistors that I use in front of the N-Mosfets, Increases the Drive voltage to the Mosfets so they should either be full on of full off, thus giving best power efficiency.
Heatsinks May be required on the Mosfets, Depending on you load Currents. For the P-Mosfet Version, The IRF4905 has a good rating. With a Proper Heatsink, it is Probably suitable for loads up to 30 amps or so.
The single transistors that I use in front of the P-Mosfets, Increases the Drive voltage to the Mosfets so they should either be full on of full off, thus giving best power efficiency.
The Loads: Although I Prefer Standard Filament Bulbs, It Can be Many LED's with there appropriate resistors or a considerable number of 12 Volt Incandescent Bulbs. Other Devices such as the 12 volt Colored Neon lights may also work. I Don't have them to give that a try.
An Etched and Drilled PCB is available for these Color Organs.
Some values on this proto board may be slightly
different than as shown on the schematic, because of
parts I have, but this will not affect performance.
Color Organ Schematic for N-Mosfet
Color Organ Overlay for N-Mosfet
Color Organ Schematic for P-Mosfet
Overlay for P-Mosfet is NOT SHOW, But Almost Identical to the N-Mosfet