Universal Vactrol Module
We call the A-101-9 an universal vactrol module. It contains two identical sub-units. Each unit has two vactrol outputs available that are controlled manually (Man control) and by an external control voltage (CV In) with attenuator (CV). A vactrol is a combination of a light depending resistor (LDR) and a light emitting diode (LED) both put into a small light-proof case. For more general details about vactrols please look at the Vactrol Basics page. Increasing the LED brightness causes a decrease of the LDR resistance. The LED at the front panel displays the brightness of the LEDs of the vactrol pair in question. The resistance of the two vactrols changes simultaneously. This allows to control two parameters at the same time or to control a parameter that requires two resistors at the same time (e.g. certain filter circuits). The LDR terminals of each vactrol are connected to the jack sockets labelled VAC1 and VAC2. In contrast to other A-100 sockets the VCA1/2 sockets are not grounded, i.e. the two terminals of the vactrol are connected to the two terminals of the socket in question.
Applications: The module introduces voltage control to any function that is controlled by a manually adjusted variable resistor (i.e. a potentiometer with only 2 terminals used). Some examples within the A-100 are: Attack, Decay, Release of all envelope generators (A-140, A-143-1, A-143-2), slew time of slew limiters (A-170), delay time and duration of trigger delay (A-162), clipping functions of the extreme filter (A-106-1), clock rate of digital noise (A-117), random rate and level (A-118), waveshaping function for A-110. A lot of application examples within the A-100 are described in the appendix of the A-101-9 user's manual. But even so far non-adjustable parameters that are determined by a fixed resistor can be made voltage controlled. But the module can be used not only within the A-100 as the vactrol outputs are completely free (no connection to A-100). The module can be used in combination with any other equipment too that uses a variable or fixed resistor to adjust a parameter (e.g. wah-wah or parameters of other effect units). Even for "circuit bending" the vactrol outputs can be used.
A midi controlled stand alone version (not an A-100 module) that will also include some switches is under development.
Latest news: The module has been redesigned with polarizer function for the CV inputs. During our tests we found that it is useful to have both directions available. For some applications a decreasing vactrol resistance with increasing control voltage is required, for other applications the opposite is the better solution. The polarizer function will avoid the need of an additional voltage inverter A-175 for the CV input. Unfortunately the front panels have been printed already. Consequently the scale of the CV controls will be not correct for the first series of the modules.
A more detailed description of the module can be found in the user's manual A1019_man.pdf
Breite/Width: 8 TE
/ 8 HP / 40.3 mm
Tiefe/Depth: 55 mm (gemessen ab der Rückseite der Frontplatte / measured from the rear side of the front panel)
Strombedarf/Current: 40 mA
|nicht mehr lieferbar / no
Price: Euro 75.00 with red LEDs
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