| C.M.S.
Module 1067 contains a professional audio grade Voltage Controlled
Amplifier designed for use in the CMS Euro-Rack Modular system.
This
high quality module is an exact replica of the special current
mirror VCA used in the ARP 2500 synthesizer. Specifically,
it is the VCA section from the 1005 and 1006 modules. These
modules were critical components of the ARP 2000/2500 modular
system. The current mirror VCA was invented by Alan R. Pearlman
in the very early days at Tonus. This VCA circuit differs
significantly from other VCA designs, including the Moog.
It
is also the same VCA circuit used in the ARP 2600, however
this VCA features significant improvements in performance
and audio quality, compared to the original VCA in the ARP
2600. This VCA exhibits low distortion, low noise and full
frequency response from D.C. control voltages to 40Khz. The
1067's voltage controlled amplifier is an extremely quiet,
responsive and transparent circuit.
The CMS 1067 has two attenuated inputs, inverting and non-inverting,
that will accept both audio and control voltages for amplitude
processing.
The
VCA also has separate, variable linear and exponential control
voltage inputs available simultaneously. A LED control monitor
provides visual feedback on each control level. This enables
precise mixing of linear and exponential control signals from
2 different sources. This feature is especially useful for
producing very percussive, punchy envelopes. A typical percussive
patch often involves patching the 1032 AR generator output
into the linear control input of the 1067 VCA, and also patching
the 1032s ADSR output into the exponential control input of
the 1067 simultaneously. The 1032s ADSR is set to a very fast
attack and decay, while the AR generator settings and amount
determines the sustain and release.
The
"INITIAL GAIN" or (GATE STATUS) control adjusts
the amplitude directly from the front panel. In most cases
this control should be set to "CLOSED" or 0. The
VCA is supplied with two 1/8th inch high level output jacks.
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