ŻŁOB MODULAR Dual VCO

The Dual VCO is a 4hp dual voltage controlled analog oscillator. Each VCO has square, triangle, and sine wave out, coarse and fine tuning controls, a control voltage input, and a switch for selecting exponential or linear cv in.

When a control voltage is inserted, the fine tune control becomes an attenuator for the incoming voltage. In exponential mode, when the attenuator is fully clockwise, the VCO will track around 5 volts per octave.

Each VCO runs from 0.2 hz (5 seconds a cycle) up to 18k hz

Very Stable, Temperature compensated

waveform outputs 10vpp

current consumption: +12v 20mA, -12v 38mA

45mm deep

There are a couple quirks to these 8038 VCOs

Below 300 hz the waveform symmetry is slightly off. triangle waves get a little uneven in the lfo range, the sine is not completely perfect to begin with the bottom trough and in the lfo range it slopes slightly, and the square turns more trapezoidal above 1khz(see scope shots)

Also it doesn’t track 1 volt per octave perfectly. usually the 1st and 3rd octave will be a couple cents off.

In linear CV mode, the incoming voltage is inverted. So, a positive voltage will actually make the pitch go down. The fine tuner also respond inversely, as it’s turned clock wise the pitch goes down.

Other than those idiosyncrasies, it is a powerful, stable dual oscillator in a small footprint with no cross talk between oscillators. It’s great for: drones and beating sine or triangle waves, cross modulating itself for interesting clocks/LFOs, creating complex waveforms/timbres through lin/exp frequency modulation.