Crest Audio X-VCA User manual

specifications
Crest Audio specification literature is available
in downloadable PDF format at our website
www.crestaudio.com
Crest Audio reserves the right to make
improvements in manufacturing or design
which may affect specification.
X-VCA
v. 1.1 4/10/00
modules
master module block
group module pair
mono input module
rear view X-VCA
stereo input module
+0/-1dB 20Hz–20kHz ref 1kHz @ +4dBu—any input to any output
any output <.01% THD 20Hz–20kHz @ +15dBu out
mic ein better-than -128dBu 20Hz–20kHz—150ohm source, 60dB gain
bus output noise less-than -80dBu—output fader @0dB, 24 channels routed
residual output noise less-than -90dBu—output fader at minimum
channel mute >90dB channel routing >80dB
channel fader attenuation >90dB aux send attenuation >75dB
< +/- 30 degrees, 20Hz– 20kHz—mic-in to main-out
mic-in XLR 4k ohm balanced—max voltage gain to left/right balanced out =98dB
line-in TRS >10k ohms balanced
left/right/mono—group, aux, matrix—monitor-out all 100 ohms balanced
headphones to drive > eight-ohms
send 50 ohms ground-compensated on TRS jack
return >10k ohms balanced on TRS jack
+4dBu max level +26dBu balanced into >1k ohms
high freq +/-15dB frequency range 1kHz–20kHz Q variable 3.0– 0.7 switchable to shelving
high-mid freq +/-15dB frequency range 400Hz–8kHz Q variable 3.0– 0.7
low-mid freq +/-15dB frequency range 100Hz–2kHz Q variable 3.0– 0.7
low freq +/-15dB frequency range 40Hz–800Hz Q variable 3.0– 0.7 switchable to shelving
all group-outputs feature: compressor with threshold, ratio and gain controls—plus soft-knee and response switches
downward expander/gate with adjustable threshold and ratio controls
linking between odd/even group-pairs preserves stereo-imaging and allows for ducking effects
main-outputs feature: five-band output eq: high and low bands—adj freq three mid-bands—adj freq and Q
left/right/mono switchable high-pass filter—40Hz @-24dB/octave
adjustable RMS output-limiters with threshold control and eight-segment gain reduction meter
five-segment LED ladder with VU-type response—displays pre-fader signal level
top red-LED warns of impending overload anywhere within the channel,lowest green-LED shows signal-present
thirteen mechanical VU-type meters with LED-illumination
eight-meters showing group-outs
three-meters showing main-outs (left/right/mono), and two dedicated solo-meters
pink-noise generator can feed the talk-back section
chassis is powder-coated 14-gauge galvanized steel with internal-bracing
modules are powder-coated 18-gauge galvanized steel with baked-epoxy screening
see dimension-drawing
one-year parts and labor—US and Canada only
frequency response
THD
noise
crosstalk
phase shift
inputs
outputs
insert
nominal output level
input channel eq
output features
channel metering
master metering
signal generator
construction
dimensions and weights
warranty
© 2000 Crest Audio Inc.

• eight VCA-masters control input and group channels
—VCA assignment may be stored via the microprocessor control system
• four-band eq and variable high-pass filter on all input channels
• mono inputs have full-parametric eq,while stereo inputs
are sweepable in all four bands
• eight-channels of dynamics include variable-ratio
COMPRESSOR/LIMITER and DOWNWARD EXPANDER (gate)
• output eq and RMS-limiters on primary stereo and mono outputs
• multiple outputs, including ALTERNATE OUTPUT,MATRIX 1–4 (option for
additional external matrix outputs) and dedicated ASSISTIVE LISTENING OUTPUTS
• direct-output on all mono input channels
• five-segment level indication on all mono input modules,with variable
intensity SIGNAL PRESENT indicator and multiple sample point PEAK indicator
• stereo solo system features switchable AFL/PFL mode and
LAST-PRESSED functions, with master SOLO CLEAR switch
• discrete bus assignment to groups,left/right and mono outputs
• true LCR panning available on mono input channels
• separate ground-compensated insert sends and balanced returns
• fully-balanced primary outputs and balanced mic and line inputs
wide range of configurations
X-VCA consoles are supplied with either 24, 32, 40, or 48 mono
input channels, plus four full-featured stereo line-input channels—
which can also serve as effect-returns. These standard configurations
include Master and Group modules—all other inputs may be
ordered as mono-mic/line or stereo-line, in four-channel blocks.
microprocessor-based muting system
The X-VCA’s straightforward microprocessor-based muting
system was co-developed with JL Cooper, and combines muting
flexibility with ease of operation. Eight manual-mute groups are
provided, each with a dedicated activation-switch, any number of
which may be activated at one-time.The system includes 128 MIDI-
based sequential scene mutes that can work alone, or in conjunction
with the manual mute groups. Scene mutes can be controlled via
external MIDI signals, and each of the 128 mute scenes may be pre-
set to issue a MIDI program-change command to an external device.
Each of the 128 mute scene locations can be used to store and recall
VCA channel-assignments, in addition to channel mute memory.
block diagram
dimensions
description features
Simplicity of operation may be desirable in a generic console
designed for users of all levels, but for the experienced profes-
sional, such products often fail to provide necessary professional
features. Rather than employing a least-common-denominator
approach, X-VCA includes those features most-desired by veter-
an front-of-house engineers. Full-parametric eq is provided on all
mono input channels. Stereo full-facility input channels are used
for effect-returns on faders, and eight-channels of dynamics are
provided on group channels. Full-
VCA control is provided, not
only on input channels, but also on group channels for maximum
control of complex mixes. Auxiliary sends may be switched
between mono or stereo operation. Five-band eq and
RMS -limiters are provided on the stereo and mono outputs,
helping to maintain control of maximum signal-levels when strict
noise ordinances are enforced.
sound fundamentals
Even in the most demanding environments, the sonic perfor-
mance of the X-VCA is sure to please discriminating sound engi-
neers and audiences alike. The X-VCA’s circuitry delivers both
extended headroom and low-noise: exclusively employing the lat-
est-generation of integrated circuits and studio-grade proprietary-
design microphone pre-amplifiers.VCA-elements are the best
available fromTHAT Corporation. The X-VCA console has
exceptional phase-shift performance, exhibiting less than +/-30
degrees-of-shift from input to output—significantly better results
than most consoles, regardless of price.
built to defy murphy’s law
X-VCA consoles are manufactured to the same exacting quality-
standards as all Crest Audio console products. Each input channel
has its own discrete vertically-mounted circuit board, for greater
impact resistance and serviceability. All circuit boards employ
plate-through double-sided glass epoxy construction—providing
greater strength and integrity. The console’s road-worthy external
frame is fabricated from 14-gauge galvanized steel.
X-Series power supplies utilize amplifier-engineering technology to
deliver stable voltages and long-term reliability, and provide built-in
facilities for a redundant back-up supply—ensuring that the show
will always go on.
X-VCA console