MODULE 2500 - VC CLOCK

The 2500, 2510, 2520 and 2560 modules perform the basic potentiometer matrix functions of early sequencers. The 2510 is an eight position (3 bit) up/down presetable, cascadable counter; the 2520 is a 4 by 8 potentiometer matrix, and the 2560 is a sequential switch.

The 2500 Voltage Controlled Clock module is a low frequency sawtooth/ pulse VCO with special gating capabilities.
The initial frequency control varies the clock rate from approximately 0.001 Hz (1 cycle/18 min.) to 500 Hz; the two leftmost frequency modulation inputs vary this center frequency with approximately 1 volt/octave sensitivity. The third FM input has sensitivity adjustable from zero through 1V/octave.
The pulse width control varies the pulse duty cycle from virtually zero to virtually 100%. However, a pulse will always be issued each cycle for correct clocking. The pulse width modulation inputs have a maximum sensitivity of 10%/volt. Pulse width modulation is such that only one rising edge can be generated each cycle.
The clock may be synchronously gated on or off. When the oscillator is turned off, it will finish the current timing cycle and then stop. When gated back on, a pulse rising edge will immediately be generated.
The switch below the lamp determines the function of the on and off input jacks. In the “pulse set” (center) position, a logical one at the “on” input turns the clock on; it may be turned off by a logical one at the “off” input. The “on” lamp is lit when the clock is running. With a logical zero at both inputs, the oscillator stays on or off as set by the most recent pulse.