How They Work

Eventually, I hope to fill this page with technical information on how Combo Organs work.  It's going to take some time, though.  Rather than put one of those cute little "Under Construction" guys with the jackhammer (please!), I thought I'd just do this.   Oh, I guess I could come up with a REAL rough diagram, just for starters - here goes:

Vibrato-->Oscillators(x12)-->Dividers(5-6each)-->Keyboard-->Busbars(1-9)-->Filters-->Preamp-->Output

Vibrato: Low frequency oscillator that varies the pitch of the...

Oscillators: One for each note in the scale(12), generates highest pitch for each.  Lower pitches created by the...

Dividers: Each successive one lowers the note by an octave.  Outputs from each are sent to the...

Keyboard: Each key routes the tone from one or more dividers to one or more buses, one for each rank (16', 8', 4', etc).  Each bus output is sent to the...

Filters: Tone shaping circuitry, usually simple Resistor/Capacitor networks to remove certain harmonics, producing different types of tones (Flute,String,Reed,etc).  Outputs are summed and sent to the...

Preamp: The end of the line.  Often includes volume, tone, reverb, sometimes expression pedal circuitry.  Output is sent to the amp.

I'm not even going to attempt to cover such things as Sustain and Percussion - maybe later......