Chameleon Labs 7721 User Manual
7721 VCA Stereo Compressor
User’s Manual
Chameleon Labs LLC, Woodinville, WA USA www.chameleonlabs.com 7721 User’s Manual
1
Important Safety Instructions
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
CAUTION AVIS
RISK OF ELECTRIC SHOCK
DO NOT OPEN
RISQUE DE CHOC ELECTRIQUE
NE PAS OUVRIR
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with a dry cloth.
7. Do not block any ventilation openings.
Install in accordance with the manufacturer’s
instructions.
8. Do not install near any heat sources such as
radiators, heat registers, stoves, or other
apparatus (including amplifiers) that produce
heat.
9. Protect the power cord from being walked on
or pinched particularly at plugs, convenience
receptacles, and the point where they exit from
the apparatus.
11.
Only use attachments/accessories specified by
the manufacturer.
12.
Use only with a cart, stand, tripod, bracket, or
table specified by the manufacturer, or sold with
the apparatus. When a cart is used, use caution
when moving the cart/apparatus combination
to avoid injury from tip-over.
13.
Unplug this apparatus during lightning storms
or when unused for long periods of time.
14.
Refer all servicing to qualified service
personnel. Servicing is required when the
apparatus has been damaged in any way, such
as power-supply cord or plug is damaged, liquid
has been spilled or objects have fallen into the
apparatus, the apparatus has been exposed to
rain or moisture, does not operate normally, or
has been dropped.
15.
This apparatus shall not be exposed to dripping
or splashing, and no object filled with liquids,
such as vases or beer glasses, shall be placed on
the apparatus.
The lightning flash with arrowhead
symbol within an equilateral triangle is
intended to alert the user to the presence
of uninsulated “dangerous voltage”
within the product’s enclosure, that may be
of sufficient magnitude to constitute a risk of
electric shock to persons.
Le symbole éclair avec point de flèche à l’intérieur
d’un triangle équilatéral est utilisé pour
alerter l’utilisateur de la présence à l’intérieur
du coffret de “voltage dangereux” non isolé
d’ampleur suffisante pour constituer un risque
d’éléctrocution.
The exclamation point within an
equilateral triangle is intended to alert
the user of the presence of important
operating and maintenance (servicing)
instructions in the literature accompanying the
appliance.
Le point d’exclamation à l’intérieur d’un
triangle équilatéral est employé pour alerter
les utilisateurs de la présence d’instructions
importantes pour le fonctionnement et
l’entretien (service) dans le livret d’instruction
accompagnant l’appareil.
Caution: to reduce the risk of electric shock, do
not remove cover (or back). No user-serviceable
parts inside Refer servicing to qualified
personnel
Attention: pour eviter les risques de choc
Electrique, ne pas enlever le couvercle. Aucun
Entretien de pieces interieures par l’usager.
Confier L’entretien au personnel qualifie.
Avis: pour eviter les risques d’incendie ou
D’electrocution, n’exposez pas cet article A la
pluie ou a l’humidite
At the end of its useful life, this product must
be carefully and correctly disposed of, and
not placed in with household waste. Please
contact your local, state, or national services
for information regarding the safe disposal of
electronic equipment.
Chameleon Labs LLC, Woodinville, WA USA www.chameleonlabs.com 7721 User’s Manual
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Introduction
Congratulations on your purchase of a fine
Chameleon Labs’ 7721 VCA Stereo compressor. We
hope that it gives you many years of reliable and
high-quality service.
• Dry/Wet control (Full Dry CCW is full
uncompressed signal, Full Wet CW is full
compressed signal
• Output Gain control (-60db to +20dB)
Your 7721 compressor has stereo inputs and outputs
and uses a voltage controlled audio engine to
generate the control voltage that provides the
amount and type of limiting and compression you
desire. It feature a highly effective VU meter, a Wet/
Dry control knob, Peak/RMS detection, Soft and Hard
knee selection as well Threshold, Attack, Release and
Compression ratio controls.
The 7721 has been carefully constructed and
individually tested for quality at our facility in
Woodinville, Washington. It utilizes an ultra low
noise pure, IC based topology.
We have spent three years developing the 7721 and
are extremely pleased to have built this unit for your
use. Although highly influenced by the famous buss
compressors of the 70’s, we have strived to introduce
significant improvements especially in the area of
increased precision for the controls, improved noise
floor and a useful set of features.
• VU Meter selector control (input and outputs
and gain reduction)
• Output Signal Overload LED (+4dB)
Rear Panel Features
• AC Power Input (IEC) and integral fuseholder
• XLR inputs
• XLR outputs
Power Supply
• Internal universal power supply
Limited Warranty
• One year
Features:
• Stereo Inputs / Outputs (balanced XLR’s)
• Selectable Side Chain input (balance XLR)
• Class A/B signal chain topology
• Peak or RMS Detection
• Hard or Soft Knee Compression
• Compression In/Out Switch
• Threshold Control - (-15dB / +15dB)
• High Pass Filter (20, 60, 90, 130 and 200Hz)
• Attack (0.10ms - 30ms)
• Release (0.10s - 1.5s)
• Compression Ratio (between 1.5:1 and 10:1)
Chameleon Labs LLC, Woodinville, WA USA www.chameleonlabs.com 7721 User’s Manual
3
Front Panel Features
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1. Power Switch
When all your connections to and from the
preamplifier have been made, use this switch
to turn the unit on or off. When the unit is
turned ON the VU meter will light up.
2. Compression
This switch turns the compression ON and
OFF. When the compression is OFF, the red
Compression Out LED is ON.
3. Knee
Select between a Soft Knee and Hard Knee
compression curve. (See Graph Page 10)
4. Side Chain
This switch selects the Side Chain input as
the reference audio signal for engaging the
compressor.
5. Detection
This switch allows you to select between Peak
and RMS Detection. The 7721 compressor
engages by analyzing the audio signal
arriving at the Left and Right inputs. Peak
detection engages by looking primarily at
the signal “peaks”. RMS detection engages
by looking at the average RMS power of the
signal waveform.
6. Input Overload
This red LED fires when the input signal
reaches +4dB of signal level.
7. High Pass Filter
This control applies a 24dB per octave High
Pass filter to the audio signal being used
for engaging the compressor. Selectable
frequecies are 20, 60, 90, 130 and 200Hz.
This control is primarily used to keep the
compressor from pumping when analyzing
audio signal with high level, low frequency
content. (See Graph Page 9)
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8. Threshold
This control establishes the level at which the
detector will be engaged. The threshold level
can be set between -15dB and +15dB.
9. Attack
This control establishes the amount of time it
takes the compressor to engage and trigger
compression. You can select between attack
times of .1 and 30 milliseconds.
10. Release
This control establishes the amount of time
it takes for the compressor to release and
return the signal to its initial gain level. The
release time is adjustable between .1 and 1.5
seconds.
11. Ratio
This control establishes the amount of gain
reduction desired which can vary between
ratios of 1.5:1 (mild) and 10:1 (aggressive).
(See Graph Page 10)
12. Blend
This control allows you to listen to an output
signal that contains a “Blend” of compressed
and un-compressed signal. When the knob is
turned full counter clockwise (full Dry), the
output signal contains only uncompressed
signal. At the detent center position the
signal blend is 50/50 and when the knob is
turned full clockwise (full Wet) the output
signal is fully compressed content. This
control blends the two signals only and does
not effect on the compressor settings.
13. Output Gain
This control allows you to boost or attenuate
the output signal level between -60 to +15
dB.
Chameleon Labs LLC, Woodinville, WA USA www.chameleonlabs.com 7721 User’s Manual
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