The Malekko Heavy Industry Dual VCA is a compact utility VCA with switchable linear and exponential response curves, dedicated input attenuators, and uni-polar modulation inputs. The linear response allows the module to behave as a classic VCA, while the exponential is ideal for percussive sounds.
Dual VCA Features
Modulation Source Input: When either an audio or control signal is routed from the Program Source Input to the Program Output jack, the signal applied to the Modulation Source Input jack controls the program level (if audio, "Volume"). Typical Modulation sources are LFO's, Envelopes, and foot pedal controllers.
Mode Switch: This panel switch controls whether the VCA responds to the Modulation Source with linear or exponential response. The Linear response being typical for VCA's, the Exponential mode provides for dynamic percussive events.
The Modulation Level: This panel control is an input attenuator. It is not uncommon for Euromodules to provide eccentric levels, especially for envelopes. The VCA is characterized for 5 Volt Modulation Sources. Sources of greater voltage swing can be attenuated to achieve proper operation for this module. When no modulation source is jacked into the VCA, an internal voltage is normalled to the Modulation Level Control to allow manual level setting or to allow the preview of a patch configuration in progress.
The Program Source Input: Being D.C. coupled, the VCA can process either audio or control program inputs. The typical input signal range includes up to +/-5 volts inputs. Signals that exceed this level will distort. Signals exceeding +/-12 volts will damage the module.
The Program Output: VCA inputs will emit from the Program Output jack at a level directly responsive to the signal state at the Modulation Input Jack. When +5 VDC is applied to the VCA, the signal path from the Program Input to Program Output is unity gain (0 dB attenuation).
General: All signals applied to the module are assumed to be less than +/-12 Volts. Exceeding this can harm the module and voids the warranty.
Program Source Input: This input is bi-polar and assumes connecting signals range up to +/-5 Volts. Levels beyond this "clip", resulting in distortion for AC signals.
Modulation Source Input: This input is uni-polar assuming a signal range of 0 to +5 volts. As Eurosignals have no authoritative specification, a Level control attenuates signals greater than +5 volts.
Linear and Exponential Modes: The front panel mode control switch selects Linear modulation response when in the fully "up" position and Exponential response mode when depressed.
Mode Switching: Depending upon module signal state, switching from Linear to Exponential mode can result in an audible click.
Mode Leveling: Due to the significant difference in the response curves of Linear vs. Exponential modes and the lack of uniform specification for Euro-control signaling, a multi-turn potentiometer is provided for user adjustment of the maximum level produced in Exponential mode. The Exponential level adjustment has been factory set to allow a 5 volt DC modulation input to produce the same peak to peak voltage swing in either Linear or Exponential modes. Some users might prefer a slight increase of level for Exponential mode when its typical use is for very short duration percussive audio events.