Instruo - Cš-L

The Cš-L is a dual oscillator similar to the Buchla 259. It features a triangle-core and a sawtooth-core VCO. You can decide which of the audio generators is used as modulator and carrier. Playing both VCOs independently from each other is possible as well. A sub-oscillator provides support in the bass range. Ring modulation, amplitude modulation and cross modulation options, a rectifier as well as two wave folders with variable symmetry allow you to create amazingly complex sounds. That leaves us with the question: Is the Cš-L really a dual oscillator, or a full-blown synthesizer voice?

The Cš-L consists of two oscillators with differing design. Their waveforms can be combined via the multiply stage. Cross modulation is possible as well. (Details on this can be found below.)

Common features of both VCOs are Coarse and Fine tune potentiometers as well as FM inputs with switchable characteristic (linear / exponential). For playing the oscillators, there are 1V / octave inputs. They can be normalized using a button.

Each oscillator comes equipped with individual outputs for several standard waveforms as well as a processed signal. The latter is generated by feeding the sine wave of the respective VCO to a wave folder. The degree of processing as well as the waveform symmetry can be influenced manually and via CV inputs with bipolar attenuators.

The features of VCO A:

• Oscillator with sawtooth-core
• Outputs for sine, triangle, saw, square, pulse with adjustable width and the wave folder
• PWM CV input with attenuator
• Hard sync connector
• LFO mode – Here, the Sync input can be used as a reset connector.

The features of VCO B:

• Oscillator with triangle-core
• Outputs for sine, triangle, square, adjustable dual pulses and the wave folder
• The square output can be used as a sub oscillator (-1 or -2 octaves)
• PWM input with attenuator
• Soft sync connector

The multiply section can be used to combine the sine waves of both oscillators. A Depth parameter allows you to adjust the intensity of the resulting sound effects. The multiply section has its own output. There are three modes of operation, in detail:

• Ring modulation
• Amplitude modulation
• Rectifier

The Index section specializes in cross modulation using both oscillators’ sine waves. The following targets are available:

• FM inputs
• Wave folder CV inputs
• Wave folder symmetry CV inputs
• PWM CV inputs

The intensity of the cross modulation is manually adjustable plus there is a CV input with bipolar attenuator.