The MOTM-300 Ultra VCO represents a milestone in analog synthesizer design. Using only the finest available circuitry, the Ultra VCO has unmatched performance where it’s needed most: stability and tracking. Using 4 separate temperature compensation servo loops, the average drift over 12 hours is typically 0.01% or about thirty times better than a Moog 921B VCO! Why do we call it the Ultra VCO? Because the tracking circuitry uses an ultra-matched differential pair transistor array that will hold over a minimum of 15 octaves! That’s twice the range of a piano.
Although we put the focus of the design on stability, the MOTM-300 is indeed a ‘full-featured’ VCO. Sine, Saw, Triangle, and Pulse waveforms are all available simultaneously. PWM (Pulse Width Modulation) with initial pulse width and depth creates complex spectra. Other features include:
Dedicated 1volt/octave input with military-spec 25ppm 0.1% summing resistor
2 separate Frequency Modulation (FM) inputs, each with it’s own attenuator
Linear FM with switchable AC or DC coupling
PWM (Pulse Width Modulation) from DC to over 15Khz
Hard and Soft sync option. Master Sync I/O jack.
Low power consumption, only requires +-15VDC @ 60ma.
All audio signals wired with coaxial cable for lowest noise and crosstalk
Low-drift op amps and precision resistors used throughout
Updated with new photos