Through-Zero VCO
Overview
This VCO uses a triangle-core design, but the true character comes from the modulation capabilities.
Through-Zero Frequency-Modulation.
Wideband FM produces rich, inharmonic tones. Three switchable sensitivity settings offer everything from simple vibrato to complex tones.
Reversing Sync.
The direction of integration in the VCO core can be reversed on the rising, falling and rising & falling edges of a signal. The trigger threshold is set by the sum of a front-panel control and external CV, so the sync. can be modulated to modify the tone of the VCO.
Pulse-Width Modulation.
The pulse output can be modulated from 0 to 100% with a dedicated PWM input.
VCO and LFO in a single module.
The frequency of the VCO can be reduced by a factor of 100 with a switch on the front panel.
Through-Zero Frequency-Modulation.
Wideband FM produces rich, inharmonic tones. Three switchable sensitivity settings offer everything from simple vibrato to complex tones.
Reversing Sync.
The direction of integration in the VCO core can be reversed on the rising, falling and rising & falling edges of a signal. The trigger threshold is set by the sum of a front-panel control and external CV, so the sync. can be modulated to modify the tone of the VCO.
Pulse-Width Modulation.
The pulse output can be modulated from 0 to 100% with a dedicated PWM input.
VCO and LFO in a single module.
The frequency of the VCO can be reduced by a factor of 100 with a switch on the front panel.
Key Data
Module Depth:
Power Connector:
Current Consumption:
Reverse-Power Protection:
Panel Width:
Panel Options:
22mm
Doepfer 16-pin shrouded header
+12 Volts, 65mA
-12 Volts, 60mA
Yes
14HP (70.8mm)
White powder-coated aluminium with blue UV-cured printing
Doepfer 16-pin shrouded header
+12 Volts, 65mA
-12 Volts, 60mA
Yes
14HP (70.8mm)
White powder-coated aluminium with blue UV-cured printing
Output Waveforms:
Frequency Range (VCO):
Frequency Range (LFO):
Modulation Inputs:
Sync. Inputs:
Sine, Saw, Triangle, Square, Pulse, Half-Frequency Square, Double-Frequency Saw.
12Hz - 18KHz
0.1Hz - 180Hz
(Both extendable with external CV)
1 x Linear FM, 3 x Exp. (1 with variable attenuator)
1 Sync. input, 1 DC offset
12Hz - 18KHz
0.1Hz - 180Hz
(Both extendable with external CV)
1 x Linear FM, 3 x Exp. (1 with variable attenuator)
1 Sync. input, 1 DC offset
Details
Video, Sound & Pictures
Through-Zero Frequency-Modulation.
Video and audio examples demonstrating the tonal qualities of linear FM. The VCO has a switch to vary the sensitivity of the FM input, and the video-clips below show the effect this has.
Video and audio examples demonstrating the tonal qualities of linear FM. The VCO has a switch to vary the sensitivity of the FM input, and the video-clips below show the effect this has.
'Lo' FM Depth.
With the FM Depth switch set to 'Lo', a modulation signal of 10vp-p will sweep the oscillator frequency down to zero and up to twice its initial frequency. Although this can produce pleasing tones, the carrier does not go through zero for nominal oscillator output levels.
With the FM Depth switch set to 'Lo', a modulation signal of 10vp-p will sweep the oscillator frequency down to zero and up to twice its initial frequency. Although this can produce pleasing tones, the carrier does not go through zero for nominal oscillator output levels.
'Med' FM Depth.
The FM modulation sensitivity is increased to 3, so the oscillator frequency is modulated between +4 and -2 times its nominal frequency. Much richer tones are produced now that the oscillator is being modulated below zero Hertz.
The FM modulation sensitivity is increased to 3, so the oscillator frequency is modulated between +4 and -2 times its nominal frequency. Much richer tones are produced now that the oscillator is being modulated below zero Hertz.
'Hi' FM Depth.
Modulation sensitivity is increased to ten times that of the 'Lo' setting. Frequency extremes are now +11 to -9 times the carrier frequency and the tones produced are pretty complex.
Modulation sensitivity is increased to ten times that of the 'Lo' setting. Frequency extremes are now +11 to -9 times the carrier frequency and the tones produced are pretty complex.
Through-Zero Modulation Example.
The LFO in a Liivatera S&H module has been used to trigger an envelope generator and sample the white output of the Liivatera Noise. The EG is set for a fast attack and slow release, and is connected the the Liivatera Dual VCA. The S&H output is connected to the CV inputs of two T-Z VCO's, the output of one modulates the FM input of the other. Here is the result.
The LFO in a Liivatera S&H module has been used to trigger an envelope generator and sample the white output of the Liivatera Noise. The EG is set for a fast attack and slow release, and is connected the the Liivatera Dual VCA. The S&H output is connected to the CV inputs of two T-Z VCO's, the output of one modulates the FM input of the other. Here is the result.
