Publication ©1997 Symetrix, Inc. Symetrix,Inc.•Lynnwood,WA USA•Tel425-787-3222•Fax425-787-3211•www.symetrixaudio.comSymetrix,Inc.•Lynnwood,WA USA•Tel425-787-3222•Fax425-787-3211•www.symetrixaudio.com
Symetrix,Inc.•Lynnwood,WA USA•Tel425-787-3222•Fax425-787-3211•www.symetrixaudio.comSymetrix,Inc.•Lynnwood,WA USA•Tel425-787-3222•Fax425-787-3211•www.symetrixaudio.com
Symetrix,Inc.•Lynnwood,WA USA•Tel425-787-3222•Fax425-787-3211•www.symetrixaudio.com
425DualCompressor/Limiter/Expander
The Compressor/Limiter/Expander shall be
a dual channel model that controls the
dynamic range of wide range, wideband
audio signals, providing compression,
peak limiting, and downward expansion
simultaneously. The unit shall occupy one
rack space (1U).
The threshold of the compressor section
shall be adjustable over a range of -40 dBu
to +20 dBu via a front panel control. When
the control is fully clockwise the section
will be in bypass mode. The input-to-
output ratio will be adjustable from 1:1 to
10:1. Control of the compressor release
time shall be program dependent within a
range set by the front panel release
425 ARCHITECTS AND ENGINEERS SPECIFICATIONS
SPECIFICATIONS
Input/Output
Maximum Input Level +20 dBu Balanced, +20 dBu Unbalanced
Maximum Output Level +25 dBu Balanced, +23 dBu Balanced (600 Ohms)
+20 dBu Unbalanced, +18 dBu Unbalanced (600 Ohms)
at onset of clipping (1% THD)
Input Impedance 43k Ohms Balanced, 30k Ohms Unbalanced
Output Impedance 300 Ohms Balanced, 150 Ohms Unbalanced
Load Impedance 600 Ohms minimum Balanced/Unbalanced
CMRR Greater than 40 dB
PerformanceData
Frequency Response 10 Hz to 60 kHz +0, -3 dB
Dynamic Range 115 dB (difference of max output and noise floor)
THD+Noise .02%, 4 dBu in, +18 dBu out, 0 dB gain reduction,
20 Hz to 20 kHz, 30 kHz low-pass filter
.04%, 4 dBu in, +4 dBu out, 10 dB gain reduction,
1 kHz, 30 kHz low-pass filter
Maximum Gain Reduction 40 dB
Output Noise -90 dBu measured at balanced output,
input terminated in 600 Ohms, 20 kHz rolloff in analyzer
Crosstalk -95 dB 1k, -95 @ 10k, +4 dBu in,
remaining channel terminated in 600 Ohms,
20 kHz rolloff in analyzer
Sidechain 100 Ohms source impedance, 800 Ohms input impedance,
TRS jack, tip is return
Compressor
Type RMS responding
Attack Time 2 mS
Release Time 180 mS to 2.5 S long-term
Auto Release 20 mS to 1 sec. (20 mS burst)
Threshold -40 dBu to +20 dBu (bypass)
Ratio 1:1 to 10:1
Limiter
Attack Time 200 µS
Release Time 100 mS
Threshold -10 dBu to +20 dBu
Ratio 20:1
Expander
Attack Time 4 mS
Release Time 250 mS to 5 S
Threshold 0 dBu to -40 dBu (bypass)
Ratio 1:1.5
Connections
Input XLR, ¼" TRS
Output XLR, ¼" TRS
Sidechain ¼" TRS (one)
Polarity pin 2 of XLR is hot, tip of TRS jack is hot
Physical
Size (hwd) 1.72 x 19 x 5.75 inches, 4.37 x 48.26 x 14.605 centimeters
Shipping Weight 8 lbs (3.63kg) net
Electrical
PowerRequirements 120V AC nominal, 60 Hz, 10 watts
220V AC nominal, 50 Hz, 10 watts
TRS female. The input circuitry shall
incorporate RFI filters. The outputs shall
be active balanced designs having equal
source impedances and terminated with
3-pin XLR (AES/IEC standard wiring), and
¼" TRS female.
The balanced inputs shall accommodate
+20 dBu signals without distortion, and
the balanced outputs shall be capable of
delivering +23 dBm into a 600-ohm load.
Overall frequency response shall be 10 Hz
to 60 kHz (+0 dB, -3 dB). THD+N shall be
0.02% measured under the following
conditions: +4 dBu input, +18 dBu output,
BYPASS switch out, 20 Hz to 20 kHz,
30 kHz low-pass filter, 0 dB gain
reduction. Residual noise output shall be
no greater than -90 dBu, measured with a
20 kHz noise bandwidth, input terminated
in 600 ohms.
When the unit is inoperative (either by loss
of power, or via the BYPASS switch), the
Specifications subject to change without notice.
control. The compressor section will have
a dedicated eight segment LED ladder that
will display the gain reduction amount.
The Compressor/Limiter/Expander shall
contain an integral peak limiter having a
20:1 ratio and adjustable threshold level. A
green LED indicator shall be provided to
indicate peak limiter activity.
A front panel switch, with LED indicator,
shall select between dual mono and stereo
master/slave operation. Each channel shall
have a bypass switch which defeats all
front panel controls for that channel.
The Compressor/Limiter/Expander shall
also contain a downward expander having
a 1:1.5 expansion ratio with threshold, and
release time controls. A four segment LED
display shall be provided to indicate the
amount of downward expansion.
The inputs shall be active balanced
bridging designs terminated with 3-pin
XLR (AES/IEC standard wiring), and ¼"
425
UNITED STATES OF AMERICA
DUAL COMPRESSOR/LIMITER/EXPANDER
425
MAXIMUM
AC INPUT
12.5W
BALANCED
BALANCED
UNBALANCED/
IN/OUT
SIDECHAIN
BALANCED
UNBALANCED
LYNNWOOD WASHINGTON,
MANUFACTURED IN
XLR PIN 1 = GND = 1/4" SLEEVE
XLR PIN 3 = LOW = 1/4" RING
XLR PIN 2 = HIGH = 1/4" TIP
IN/OUT
SIDECHAIN
INPUTOUTPUT
BALANCED
BALANCED
UNBALANCED/
BALANCED
UNBALANCED
INPUTOUTPUT
SLEEVE=GROUND
RING=SEND
TIP=RETURN
IN/OUT
SIDECHAIN
inputs and outputs shall be wired together.
There shall be no transients transmitted to
the output terminals during either turn-on,
turn-off, or bypass operation.
Access to each channel’s sidechain shall
be provided via a single 1/4" TRS female
connector. The ring connection shall be
the sidechain output and the tip
connection shall be the sidechain return.
The unit shall be capable of operating by
means of its own built-in power supply
connected to 117V nominal ac (105 to
130V) 50/60 Hz (230V nominal, 207 to
253V ac, 50 Hz where applicable). The
AGC shall be Listed by Underwriters
Laboratories, Inc. (UL) or other equivalent
nationally recognized safety testing
agency.
The unit shall be a Symetrix Incorporated
model 425 Dual Compressor/Limiter/
Expander.
