The module is split into 2 parts, a basic sine oscillator, and a multi frequency oscillator. There is no internal prepatching thus allowing multiple operation modes: linear FM in four quadrants (also called through zero FM) and as well as independent patching. The origins of this technology are in analog computation and the module presents itself to the user accordingly.
The variable harmonic oscillator has 2 outputs, F(X) and ΣF(X)dt, which are equivalent to the 0 and 90 degree phase shift between Sine and Cosine, meaning these modules can be paired with a balanced modulator to give frequency shifting effects. The frequency content of this output is made up of a group of sine waves whose harmonic relationship and amplitude is determined by the Evolve control, equivalent to the harmonic scan parameter found in a digital wavetable. Here, this parameter behaves more like a tuning or sync control than a digital wavetable oscillator, as the computation is done in real time rather than scanning between predetermined solutions. This takes some getting used to but the results are sonically interesting, more so in combination frequency modulation.
Each oscillator has two 1v/Octave inputs dedicated to it that are summed together, under the row of 4, the 2 on the left are for the Sine oscillator and 2 on the right are for the variable harmonic. The outermost inputs on each side have a switch underneath that can invert the signal (so the values from your sequencer are subtracted instead of added). The Evolve harmonic control also has a 1v/oct input with switch (be aware the Evolve 1v/oct input cannot accept negative voltages, negative voltages can only be accessed by using the panel switch to invert a positive voltage internally).
The module exists beyond the limits of analog circuitry, and expectations about performance are better to be set in advance if expecting performance like a digital VCO. Exponential control in the main oscillator is poor, and the circuitry that gives excellent distortion performance unfortunately can cause AM artifacts, but these can be minimised with good playing ability. 1v/oct scaling in the Sine / Modulation oscillator is excellent, on the other hand.
The carrier oscillator is relatively limited in it’s range compared to other analogue oscillators, working at a fundamental frequency of 1hz to 6khz . Harmonic control allows output frequencies many octaves above this.
Current consumption: +/-250mA. Operation voltage is +/-15V DC
Processing resolution: theoretically infinite.
Safe studio practice for working with electronic devices (moreso those in metal casing) necessitates 0V / signal ground on the power supply being linked to mains earth. Hinton Instruments Full Power PSU exceeds the necessary requirements for a low noise, reliable and safe supply.
Output impedances 100 ohm. Input impedances for audio and ordinary control are 10k ohm. 1v/oct are many Gigohm.
Audio output voltages are roughly +/-10V (20V peak to peak).