Symetrix 422 User manual

i
Model 422
Stereo AGC/Leveler
Revision 1.0, 7 June, 1995
Symetrix part number: 530422
Subject to change at our whim and fancy, without notice.
Copyright 1995, Symetrix, Inc. All rights reserved.
Symetrix is a registered trademark of Symetrix, Inc.
Mention of third-party products is for informational purposes only and
constitutes neither an endorsement nor a recommendation. Symetrix
assumes no responsibility with regard to the performance or use of these
products.
Under copyright laws, no part of this manual may be reproduced or
transmitted in any form or by any means, electronic or mechanical,
including photocopying, scanning, recording or by any information
storage and retrieval system, without permission, in writing, from
Symetrix, Inc.
User's Guide
Symetrix, Inc.
14926 35th Ave West
Lynnwood, WA 98037 USA
voice: [phone]
fax: [phone]
CompuServe: 102102,1126

ii
1 Introduction 1
2 Safety Information 2
Operator safety summary 2
Other safety information 3
3 Summary Product Description
Front panel view 4
Rear panel view 5
4 Installation 6
AC line connection 6
Mounting in an equipment rack 6
Recommended audio cable wiring 7
5 Operation 8
TheTARGET LEVEL control 8
The DETECTOR control 8
The RATIO control 8
The PEAK LIMIT control 9
The SYSTEM BYPASS/IN button 9
The INPUT and OUTPUT level meters 9
6 Troubleshooting 10
Solutions to common problems 10
Less common problems 10
7 Warranty and Service 11
The Symetrix 422 LimitedWarranty 11
Servicing the 422 12
Return Authorization 12
In-warranty repairs 12
Out-of-warranty repairs 12
Appendix A Specifications 13
Architects and engineers specifications 13
Technical specifications 13
Appendix B REMOTE BYPASS wiring 14
Contents

Page 1
Introduction
Congratulations on your decision to use a Symetrix model 422 Stereo AGC/Leveler. The 422 has
been designed to give professional audio users unequaled performance, ease of use, and reliabil-
ity. This manual will guide you through installation and operation of the 422, and provide valu-
able tips on how to interface with other equipment in your system.
The 422 is a singular solution for controlling unpredictable stereo (or monaural) audio levels in a
wide variety of audio systems. Application environments include broadcast, recording, tape
duplication and installed foreground and background systems just to name a few. The 422 excels
at subtly and unobtrusively bringing level divergent audio into a 'target window', resulting in
greater intelligibility and informational perception. Unlike compressor/limiters, which are
effective at reducing sounds that are too loud (pushing down from the top only), the 422 provides
both downward compression and upward leveling by gently adding gain to low level signals until
a target level is reached.
The 422 employs advanced analog signal processing technology executed with high quality
industrial grade components to meet, or exceed, the highest professional audio industry standards
in terms of headroom, low noise and distortion, and superb sonic qualities.
The 422's logical control panel holds no hidden surprises. The product is easy to learn and simple
to use. In the sections that follow, you'll find information on installation, operation, and specific
applications of the 422. We follow this with a troubleshooting guide, warranty and service
information, and detailed specifications.
As with all Symetrix products, the 422 is intended to provide you with years of trouble free use.
Our company is committed to excellence in product design, manufacturing, and customer satis-
faction. Please do not hesitate to contact us with your questions or comments.
1

Page 2
Safety Information
Operator safety summary
The information in this summary is intended for persons who operate the equipment as well as
repair personnel. Specific warnings and cautions are found throughout this manual wherever they
may apply; they do not appear in this summary.
The notational conventions used in this manual and on the equipment itself are described in the
following paragraphs.
Equipment markings
The lightning flash with arrowhead symbol
within an equilateral triangle is intended to
alert the user of the presence of uninsulated
"dangerous voltage" within the product's
enclosure that may be of sufficient magni-
tude to constitute a risk of electric shock to
persons.
The exclamation point within an equilateral
triangle is intended to alert the user of the
presence of important operating and mainte-
nance (servicing) instructions in the litera-
ture accompanying the 422 (i.e. this
manual).
CAUTION
WARNING:
ATTENTION:
RISQUE DE CHOC ELECTRIQUE
NE PAS OUVRIR
S’adresser a un reparateur compétent.
THIS EQUIPMENT TO RAIN OR MOISTURE
ELECTRIC SHOCK DO NOT EXPOSE
TO REDUCE THE RISK OF FIRE OR
No user serviceable parts inside. Refer servicing to qualified service personnel.
Il ne se trouve a l’interieur aucune piece pourvant entre reparée l’usager.
DO NOT OPEN
RISK OF ELECTRIC SHOCK
Caution
To prevent electric shock, do not use the polarized plug supplied with the 422 with any extension
cord, receptacle, or other outlet unless the blades can be fully inserted to prevent blade exposure.
Terms
Several notational conventions are used in this manual. Some paragraphs may use Note, Caution,
or Warning as a heading. These headings have the following meaning:
Note Identifies information that needs extra emphasis. A Note generally supplies extra
information to help you to better use the 422.
Caution Indentifies information that, if not heeded, may cause damage to the 422 or
other equipment in your system.
Warning Identifies information that, if ignored, may be hazardous to your health or
that of others.
In addition, certain typefaces and capitalization are used to identify certain words. These are:
CAPITALS Controls, buttons or other markings on the 422's chassis.
Boldface Strong emphasis.
2

Page 3
Other safety information
Power source
This product is intended to operate from a power source that does not apply more than 255V rms
between the power supply conductors or between either power supply conductor and ground. A
protective ground connection, by way of the grounding conductor in the power cord, is essential
for safe operation.
Grounding
The chassis of this product is grounded through the grounding conductor of the power cord. To
avoid electric shock, plug the power cord into a properly wired receptacle before making any
connections to the product. A protective ground connection, by way of the grounding conductor
in the power cord, is essential for safe operation.
Danger from loss of ground
If the protective ground connection is lost, all accessible conductive parts, including knobs and
controls that may appear to be insulated, can render an electric shock.
Proper power cord
Use only the power cord and connector specified for the product. Use only a cord that is in good
condition.
Proper fuse
The power line fuse is mounted internally and is not considered user serviceable. The fuseholder
accepts American sized fuse (1/4 inch diameter) or European sized fuses (5mm diameter). For
117 VAC operation, the correct value is 1/2A, 250VAC, fast blowing (Bussman type AGC). For
230VAC operation, the correct value is 1/4A, 250VAC, slow blowing (Bussman type MDL or
GDC).
Operating location
Do not operate this equipment under any of the following conditions: explosive atmospheres, in
wet locations, in inclement weather, improper or unknown AC mains voltage, or if improperly
fused.
Stay out of the box
To avoid personal injury or injury to others, do not remove the product covers or panels. Do not
operate the product without the covers and panels properly installed.

Page 4
3Summary Product Description
This chapter provides a basic overview of the 422 by describing the input and output audio
connections, power connection, operating controls, and front panel LED indicators. Use this
information to acquaint yourself with the product. Chapter 4 (Installation) gives details on
installing the 422 in your system, and Chapter 5 (Operation) gets into specific applications and
operation of the 422 in detail.
Front panel view (left)
•The DETECTOR establishes an audio reference for the purpose of discriminating between
noise and useful audio. The 422 will not attempt to apply leveling (upward gain increases) to
signals that fall below the detector threshold.
•The RATIO control sets the amount of downward compression for signals exceeding the
target level as well as the amount of upward leveling for signals below the target level.
•The TARGET LEVEL control establishes a nominal gain goal. For signals below the target
level the 422 adds gain and boosts them upward. Signals above the target level are reduced in
gain (downward towards the target).
DETECTOR RATIOTARGET LEVEL
Front panel view (right)
•The PEAK LIMIT control determines the level at which peak limiting gain reduction begins.
Signals exceeding this threshold will be reduced by a ratio of approximately 15:1 (an increase of
15dB at the input results in only 1 dB increase at the output).
•The BYPASS/IN button activates relays which route the 422 input signals directly from the
input connectors to the output connectors when in the BYPASS position.
The INPUT/OUTPUT LED displays indicate the higher of either left or right channel calibrated
in VU (volume units). ('0' VU=+4dBu).
PEAK LIMIT
SYSTEM BYPASS/IN INPUT/OUTPUT LED displays
STEREO AGC/LEVELER
422
+60VU +12
INPUT
CLIP+120VU +6
OUTPUT
-18-24 -12-42-48 -36 -30INBYPASS
PEAK LIMIT SYSTEM
-12-24 -18-36-48 -42 -30
IN
BYPASS
BYPASS
+15
0
-8
BYPASS
-15
EASE
LIMIT
THRESHOLD (Vu)
-6
-6
EL
THRESHOLD (Vu) INPUT : OUTPUT OUTPUT LEVEL
T
-5
2.5 : 1
-
INCREASE
5 : 1 DECREASE
BYPASS
-20
-45
LIMIT
422
P
DETECTOR RATIO TARGET LEVEL

Page 5
LEFT INPUT audio connectors
Rear panel view (left)
•The AC INPUT connector accepts nominal AC power sources of 117 volts or 230 volts [see
Appendix A (Specifications) for voltage tolerance ranges]. See chapter 4 (Installation) for details
on the detachable (IEC) power cable.
•The REMOTE BYPASS connector provides for the control of the BYPASS/IN function via a
remote contact closure. See Appendix B, REMOTE BYPASS WIRING, for details.
•The LEFT INPUT audio connectors are electronically balanced, bridging, line level inputs.
XLR pin 1 is ground, pin 2 is high, and pin 3 is low. The 1/4" connector's sleeve is ground, ring is
low, and tip is high.
•The LEFT OUTPUT audio connectors are electronically balanced, low impedance, line level
outputs. XLR pin 1 is ground, pin 2 is high, and pin 3 is low. The 1/4" connector's sleeve is
ground, ring is low, and tip is high.
AC INPUT connector REMOTE BYPASS connector
LEFT OUTPUT audio connectors
Rear panel view (right)
RIGHTRIGHT
OUTPUTS INPUTS
XLR Pin 2 is HIGH.
be Balanced or Unbalanced.
Input and Output connections may
PIN 3 = RING = LOW
PIN 2 = TIP = HIGH
PIN 1 = SLEEVE = GROUND
TYPICAL CONNECTIONS:
RIGHT OUTPUT audio connectors
•The RIGHT INPUT audio connectors are electronically balanced, bridging, line level inputs.
XLR pin 1 is ground, pin 2 is high, and pin 3 is low. The 1/4" connector's sleeve is ground, ring
is low, and tip is high.
•The RIGHT OUTPUT audio connectors are electronically balanced, low impedance, line level
outputs. XLR pin 1 is ground, pin 2 is high, and pin 3 is low. The 1/4" connector's sleeve is
ground, ring is low, and tip is high.
Note For optimum immunity to noise and radio frequency interference we highly recommend
connecting the 422 to balanced equipment, where possible. If this is not possible, unbal-
anced connections are OK. Unbalanced connections via tip-sleeve (mono) 1/4" plugs are
easy to make via the 422's 1/4" input and output connectors.
RIGHT INPUT audio connectors
POWER
THIS UNIT IS
REMOTE
BYPASS OUTPUTS INPUTS
AC INPUT
LEFT
422
STEREO AGC/LEVELER
12.5W
LEFT
MANUFACTURED IN
LYNNWOOD, WA, U.S.A.
MAX

Page 6

Page 7
Male 1/4" tip-ring-sleeve plug
Tip = high
Ring = low
Sleeve = ground
Male 1/4" tip-sleeve plug
Tip = high
Sleeve = ground
Male 1/4" tip-ring-sleeve plug
Tip = high
Ring = low
Sleeve = ground
Male 1/4" tip-sleeve plug
Tip = high
Sleeve = ground
Ring
Sleeve
Tip

Page 8
5Operation
This section describes in detail the functions of the 422's front panel controls and LED indicators.
TheTARGET LEVEL control
When setting up the 422, this is generally the control that you should adjust first. The TARGET
LEVEL control does just what the name implies. It establishes the volume where you want it.
Technically, the control sets a threshold. Incoming signals that exceed this threshold are com-
pressed downward towards the threshold. Incoming signals below the threshold are expanded
(leveled) upward towards the threshold. The 422's output is a reduced dynamic range replica of
its input, 'centered' around the target level.
As you adjust the TARGET LEVEL control, it's very easy to see and hear the results. A quick
glance at the OUTPUT level VU meter will show you the exact effects of increasing or decreas-
ing TARGET LEVEL.
The DETECTOR control
The DETECTOR control increases or decreases the sensitivity of the 422 to low level audio
signals and noise. As you turn this control counterclockwise, the 422 'reaches down' and in-
creases the gain of low level audio and/or noise. The optimum setting of this control is entirely
dependent upon the nature of the audio that the 422 is processing. For example, if the audio
source is relatively clean and quiet (like a CD), the position of the DETECTOR may be noncriti-
cal. To greatly increase the volume of the low level signals on the CD, try a full counterclockwise
setting of the control (-45). On the other hand, if you try the same extreme setting with a noisy
cassette recording, you may not find the results to be pleasing. If you're processing a very noisy
source, then turn the detector control clockwise towards the -20 setting until the desired sound is
achieved.
If you're unsure of where to position the DETECTOR control, then start with it straight up in the
twelve o'clock position. We've found this to be a good compromise for unpredictable audio
sources.
The RATIO control
The RATIO control is used to increase or decrease the degree of leveling. At high ratios, the
program density increase results in a more 'present' or 'up front' sound. At low ratios, the 422
performs subtle, yet effective, automatic gain riding. At a setting of 5:1 (maximum) the effect of
the 422 AGC/leveling process is very audible.
The optimum setting of this control is usually dictated by the particular type of material one is
processing, and the desired effect. For example, if the 422 is part of a foreground/background
music/paging system in a high ambient noise environment, a higher ratio will produce maximum
intelligibility. As part of a broadcast chain, where the process itself must be as subtle as possible,
a 2.5:1 or lower ratio is advisable.
If you're unsure of where to position the ratio control, then we suggest you start in the twelve
o'clock position and make upward and downward adjustments from there as you listen and
evaluate the results.

Page 9
The PEAK LIMIT control
The PEAK LIMIT control sets an absolute 'ceiling' threshold level to which the maximum output
level is limited. The control is calibrated in VU (volume units). The PEAK LIMITER is useful in
any application where it is desired to prevent overload of subsequent system components. This
may include applications such as high volume music systems in clubs and theatres, or transmis-
sion line applications such as AM/FM radio and television.
When the control is turned to its full clockwise rotation, the PEAK LIMITER is bypassed. As the
control is rotated counterclockwise, the threshold is moved lower and the resultant limiting can
be observed as a reduction in overall output level on the OUPUT LED meter.
The optimum setting for the PEAK LIMIT control is most often correlated directly to require-
ments of 'downstream' system components. If you're unsure of where to set the control, then you
may want to try this: observe the OUTPUT level display and note the average output level, then
adjust the PEAK LIMIT control 10-12dB above the average output level. Set this way, the peak
limiter will provide protection without over limiting the signal. The LIMIT LED should only
come on occasionally. If it stays on constantly then your are applying too much limiting and
should turn the PEAK LIMIT control clockwise to reduce the amount of limiting. If you do not
have a clearly identified need to peak limit your signal, then we recommend that you turn the
PEAK LIMIT control to the fully clockwise BYPASS position.
The SYSTEM BYPASS/IN button
The BYPASS/IN button places the 422 in either BYPASS or IN(circuit) modes. In BYPASS mode
the incoming signals are directly routed (via relays) to the 422's outputs, thereby bypassing any
internal circuitry. In BYPASS mode the front panel rotary controls have no effect on the operation
of the 422. A red LED indicates BYPASS status, while a green LED indicates IN status.
The INPUT and OUTPUT level meters
The INPUT and OUTPUT level meters are calibrated in VU (volume units). The meters read the
greater of either left or right channel signal levels. The meters give an indication of absolute
signal levels, and show the exact relationship between input and output signals as a result of
various settings of the 422's controls.

Page 10
6Troubleshooting
Solutions to common problems
There is no output signal
Check the AC power connections to the 422.
Check input and output cables and connections.
Determine that there really is a signal coming from the source and that it is getting to the 422.
Distortion in the output signal
Check the input signal. Is it overdriving the 422's input?
Is the incoming signal already distorted? Listen 'up stream' from the 422 (or manually place the
unit in BYPASS mode) to determine that you are feeding it a clean signal.
Buzz in the output
Check input and output connector wiring.
Check for ground loops between interconnected system equipment.
Are all system components on the same AC ground?
Noise (hiss)
Check input signal levels and input level control settings. The input may be too low in level. If
so, boost the signal from your console or input source.
Is the input signal already noisy? Disconnect the inputs from the 422 and listen for noise at the
output. If the noise is gone, then the problem is prior to the 422.
Less common problems
The 422 doesn't power up or doesn't respond properly.
Consult a qualified service technician or the Symetrix factory.
The 422 is not plugged in, but works great anyway.
Consult your doctor or therapist.

Page 11
7Warranty and Service
The Symetrix 422 LimitedWarranty
Symetrix, Inc. expressly warrants that the product will be free from defects in material and
workmanship for one (1) year. Symetrix's obligations under this warranty will be limited to
repairing or replacing, at Symetrix's option, the part or parts of the product which prove defective
in material or workmanship within one (1) year from date of purchase, provided that the Buyer
gives Symetrix prompt notice of any defect or failure and satisfactory proof thereof. Products
may be returned by Buyer only after a Return Authorization number (RA) has been obtained from
Symetrix. Buyer will prepay all freight charges to return the product to the Symetrix factory.
Symetrix reserves the right to inspect any products which may be the subject of any warranty
claim before repair or replacement is carried out. Symetrix may, at its option, require proof of the
original date of purchase (dated copy of original retail dealer's invoice). Final determination of
warranty coverage lies solely with Symetrix. Products repaired under warranty will be returned
freight prepaid via United Parcel Service by Symetrix, to any location within the Continental
United States. Outside the Continental United States, products will be returned freight collect.
The foregoing warranties are in lieu of all other warranties, whether oral, written, express,
implied or statutory. Symetrix, Inc. expressly disclaims any IMPLIED warranties, includ-
ing fitness for a particular purpose or merchantability. Symetrix's warranty obligation and
buyer'sremedies hereunder are SOLELY and exclusively as stated herein.
This Symetrix product is designed and manufactured for use in professional and studio audio
systemsand is not intended for other usage. With respect to products purchased by consumers for
personal, family, or household use, Symetrix expressly disclaims all implied warranties,
including but not limited to warranties of merchantability and fitness for a particular
purpose.
This limited warranty, with all terms, conditions and disclaimers set forth herein, shall extend to
the original purchaser and anyone who purchases the product within the specified warranty
period.
Warranty Registration must be completed and mailed to Symetrix within thirty (30) days of the
date of purchase.
Symetrix does not authorize any third party, including any dealer or sales representative, to
assume any liability or make any additional warranties or representation regarding this product
information on behalf of Symetrix.
This limited warranty gives the buyer certain rights. You may have additional rights provided by
applicable law.
Limitation of Liability
The total liability of Symetrix on any claim, whether in contract, tort (including negligence) or
otherwise arising out of, connected with, or resulting from the manufacture, sale, delivery, resale,
repair, replacement or use of any product will not exceed the price allocatable to the product or
any part thereof which gives rise to the claim. In no event will Symetrix be liable for any inciden-
tal or consequential damages including but not limited to damage for loss of revenue, cost of
capital, claims of customers for service interruptions or failure to supply, and costs and expenses
incurred in connection with labor, overhead, transportation, installation or removal of products or
substitute facilities or supply houses.

Page 12
Servicing the 422
If you have determined that your 422 requires repair services and you live outside of the
United States please contact your local Symetrix dealer or distributor for instructions on how to
obtain service. If you reside in the U.S. then proceed as follows.
Return authorization
At the Symetrix factory, Symetrix will perform in-warranty or out-of-warranty service on any
product it has manufactured for a period of five years from date of manufacture.
Before sending anything to Symetrix, please contact our Customer Service Department for a
return authorization (RA) number. The telephone number is [phone], Monday through
Friday, 8AM (800 hours) though 4:30 PM (1630 hours), Pacific Time.
In-warranty repairs
To get your 422 repaired under the terms of the warranty:
1. Call us for an RA number.
2. Pack the unit in its original packaging materials.
3. Include your name, address, daytime telephone number, and a brief statement of the problem.
4. Write the RA number on the outside of the box.
5. Ship the unit to Symetrix, freight prepaid. We do not accept freight collect shipments.
Just do these five things, and repairs made in-warranty will cost you only one way freight
charges. We'll pay the return freight.
If you choose to send us your product in some sort of flimsy, non-Symetrix packaging, we'll have
to charge you for proper shipping materials. If you don't have the factory packaging materials,
then do yourself a favor by using an oversize box. Wrap the unit in a plastic bag, surround it with
bubble-wrap, and place it in the box surrounded by Styrofoam peanuts. Be sure there is enough
clearance in the box to protect the rack ears (you wouldn't believe how many units are returned
with bent ears). We won't return the unit in anything but Symetrix packaging, for which we will
have to charge you. Of course, if the problem turns out to be operator inflicted, you'll have to pay
for both parts and labor. In any event, if there are charges for the repair costs, you will pay for the
return freight. All charges will be COD unless you have made other arrangements (prepaid, Visa
or Mastercard).
Out-of-warranty repairs
If the warranty period has passed, you'll be billed for all necessary parts, labor, packaging materi-
als, and freight charges. Please remember, you must call for an RA number before sending the
unit to Symetrix.

Page 13
A
appendix Specifications
Architects and engineers specifications
The Automatic Gain Controller (AGC/Leveler) shall be a stereo model that reduces the dynamic range of wide range,
wideband audio signals and provides peak limiting. The AGC shall occupy one rack space (1U).
The AGC/Leveler shall be capable of controlling audio signals ranging from -40dBu to +24dBu and reducing their
range by an input/output ratio of from 1:1 to 5:1. A target output level control shall be provided to shift the level of the
output signal over a nominal + 20dB range. The release time of the AGC shall be controlled by the presence and nature
of input signals.
The AGC/Leveler shall also contain an integral peak limiter having at least a 15:1 ratio and adjustable threshold level.
A red LED indicator shall be provided to indicate peak limiter activity. The peak limiter threshold shall determine the
absolute maximum output amplitude of the AGC/Leveler regardless of other conditions.
The AGC/Leveler shall provide identical peak responding input and output level meters. These meters shall be capable
of responding to signals ranging from -48VU to +12VU (-44dBu to +16dBu). An output clipping indicator shall be
provided.
The inputs shall be active balanced bridging designs terminated with 3-pin XLR (AES/IEC standard wiring) female and
1/4" (tip-ring-sleeve) jacks.
The outputs shall be active balanced designs terminated with 3-pin XLR (AES/IEC standard wiring) male and 1/4"(tip-
ring-sleeve) jacks.
Overall frequency response shall be 20Hz to 20kHz, ±1dB, measured at +4dBv output. There shall be no more than
0.02% harmonic distortion measured under the following conditions: +4dBu input, +4dBm output, BYPASS switch in,
1000Hz test frequency. Residual noise output shall be no greater than -90dBu measured in a 20kHz noise bandwidth
with an rms responding meter.
When the unit is inoperative (either by loss of power, or via the BYPASS switch), the inputs and outputs shall be wired
together. A REMOTE BYPASS facility shall be provided whereby an external contact opening shall force the AGC/
Leveler into BYPASS mode.
The AGC/Leveler 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 and 230V nominal ac (207 to 253V ac). The AGC/Leveler shall be listed by Underwriters
Laboratories, Inc. (UL) .
The AGC/Leveler shall be a Symetrix, Incorporated model 422 Stereo AGC-Leveler.
Technical specifications
Audio
Inputs Stereo,balancedbridgingorunbalanced
Outputs Stereo,balancedorunbalanced
Maximuminputlevel +24dBu
Maximumoutputlevel +22dBuinto600 ohms
Frequency Response 20Hz-20kHz, ±1dB
THD+noise .05%, 0dBu in, 10dB
gain reduction, 1kHz
OutputNoise -90dBu, broadband
DynamicRange >110dB
Crosstalk -60dB,+20dBuin,20Hz-20kHz
Inputcommonmoderejection >40dB@1kHz
AGCDetector range -41dButo -21dBu
Ratio 1:1 to 5:1
Targetlevelrange 40dB
LimiterThreshold -15dBu to +25dBu
LimiterRatio >15:1
Physical
Inputconnectors 1/4"tip-ring-sleeve,XLR,&RCA
Outputconnectors 1/4"tip-ring-sleeve,XLR,&RCA
Polarity tipofinputjackishigh,ringislow,sleeveisground
tipofoutputjackishigh,ring is low, sleeveisground
Chassissize 1.75"Hx19"Wx5.75D
4.45cmH x 48.3cmW x 14.61cmD
Shippingweight 8lbs,3.63kg
Electrical
Power 117V ac, nominal, 105-130V ac ,50-60Hz
230V ac, nominal, 207-255V ac, 50Hz
Power Consumption 12 watts
In the interest of continuous product improvement, Symetrix,
Inc.reserves the right to alter, change, or modify these
specifications without prior notice.
Copyright 1995, Symetrix, Inc.All rights reserved.

Page 14
B
appendix REMOTE BYPASS wiring
For those installations that may require remote bypassing of the 422's functions, a rear panel jack
has been provided to accept an external switch for this purpose. The external switch should be a
high quality, industrial grade, single pole, double throw toggle switch. We highly recommend that
shielded wire be used to connect the switch to the 422 so as to minimize the possibility of intro-
ducing any radio frequency interference into the 422. The external 1/4" audio plug should be of
the tip-sleeve type (often referred to as a 'mono' plug). The following diagram illustrates recom-
mended wiring practice.
The cable should be wired as shown above and as described below:
1) The tip of the 1/4" plug is soldered to one end of the 'signal' wire of a coaxial cable.
2) One end of the shield of the coaxial cable is soldered to the sleeve of the 1/4" plug.
3) The other end of the 'signal' wire is soldered to the common terminal of a single pole, double
throw switch.
4) The remaining shield is soldered to either of the remaining terminals of the switch (one
terminal remains unconnected).
User supplied remote bypass circuitry
Bypass
In (operate)