Symetrix 581E User manual

User’s Guide
581E Distribution Amplifier

User’s Guide
581E Distribution
Amplifier
1/11
Before You Begin
What Ships in the Box
RA 581E hardware unit.
RA detachable power cord.
RThis User’s Guide.
Getting Help
If you have questions beyond the scope
of this User’s Guide or the help module,
contact our Customer Support Group in
the following ways:
Tel [phone]
8:00 am to 4:30 pm
Monday through Friday,
Pacific Time
Web support.symetrixaudio.com
Important Safety Instructions.
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near
water. This apparatus shall not be
exposed to dripping or splashing and
no objects filled with liquids, such as
vases, shall be placed on the appara-
tus.
6. Clean only with dry cloth.
7. Do not block any ventilation open-
ings. Install only 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. This apparatus shall be connected
to a mains socket outlet with a
protective earthing connection. Do
not defeat the safety purpose of the
polarized or grounding-type plug. A
polarized plug has two blades with
one wider than the other. A grounding
type plug has two blades and a third
grounding prong. The wide blade or
the third prong are provided for your
safety. If the provided plug does not
fit into your outlet, consult an electri-
cian for replacement of the obsolete
outlet.
10.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 the 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 com-
bination to avoid injury from tip-over.
13.Unplug this apparatus during light-
ning 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 cord 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.
AVIS:
NE PAS OUVRIR
Il ne se trouve a l’interieur aucune piece pourvant entre reparée l’usager.
SEE OWNERS MANUAL. VOIR CAHIER D’INSTRUCTIONS.
S’adresser a un reparateur compétent.
RISQUE DE CHOC ELECTRIQUE
No user serviceable parts inside. Refer servicing to qualified service personnel.
CAUTION
WARNING:
TO REDUCE THE RISK OF FIRE OR
ELECTRIC SHOCK DO NOT EXPOSE
THIS EQUIPMENT TO RAIN OR MOISTURE
DO NOT OPEN
RISK OF ELECTRIC SHOCK
The lightning flash with arrowhead
symbol within an equilateral triangle is
intended to alert the user of the pres-
ence of uninsulated “dangerous voltage”
within the product’s enclosure that may
be of sufficient magnitude 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
maintenance (servicing) instructions in
the literature accompanying the product
(i.e. this User’s Guide).
CAUTION To prevent electric shock,
do not use the polarized plug supplied
with the unit with any extension cord,
receptacle, or other outlet unless the
prongs can be fully inserted.
Power Source. The 581E Distri-
bution Amplifier hardware is configured
at the factory for domestic or export
markets. Ensure that your AC mains
voltage matches that of your power
supply. Refer to rear panel marking for
correct AC source voltage. Use only the
power cord and connector specified for
the product and your operating locale.
A protective ground connection, by way
of the grounding conductor in the power
cord, is essential for safe operation. The
appliance inlet and coupler shall remain
readily operable once the apparatus has
been installed.
User Serviceable Parts. There
are no user serviceable parts inside the
581E Distribution Amplifier. In case of
failure, customers inside the U.S. should
refer all servicing to the Symetrix factory.
Customers outside the U.S. should refer
all servicing to an authorized Symetrix
distributor. Distributor contact information
is available online at
www.symetrixaudio.com.

User’s Guide
581E Distribution
Amplifier
2/11
Introduction
The Symetrix 581E Distribution Amplifier (4x4) is a four-input, sixteen-output distribution amplifier. In a typical configuration the
581E accepts four balanced input signals and distributes each input to four independent outputs. The volume of each of the
sixteen outputs may be individually trimmed via its front panel potentiometer. Similarly, the volume of each of the four inputs
may be independently controlled. Associated with each input is a four LED level meter to assist the user in setting optimum
operating levels. The balanced input stages are designed for high common mode rejection and RF immunity. Output line
drivers are stable short-circuit protected and designed around industry standard 5532 type op amps. The 581E operates from
an internal power supply built around a low magnetic field toroidal transformer, resulting in a very low noise, high performance
product.
The 4x4 architecture of the 581E allows the amplifier to fit the greatest possible number of configurations. Each one input,
four output module is independent of the others. Wiring the 581E’s inputs to four separate audio sources provides four mono
distribution channels with four outputs each. This configuration also accommodates two stereo audio feeds.
Stereo audio can be distributed to eight inputs by strapping the 581E’s inputs together in pairs. Left channel audio is wired to
inputs #1 and #2, while the right channel connects to inputs #3 and #4.
The 581E distributes a single mono audio source to all 16 outputs when all inputs are strapped together. Regardless of your
audio distribution requirements, the Symetrix 581E solves the problem with minimum cost and no wasted outputs.
Fast First Time Setup
Follow these instructions to get your 581E up-and-running as quickly as possible. The intent of this section is fast setup. Refer
to later chapters for explanation of the 581E’s controls and functions.
Connect audio inputs and outputs. If you do not know how to do this, forget Fast Setup and skip to the Rear Panel Over-
view.
Set INPUT level trim controls straight up (12 o’clock position).
Set OUT level trim controls at maximum level (clock-wise rotation).
Plug the 581E into an AC outlet using the IEC-type detachable power cord provided with the unit.
Caution: Failure to connect the 581E to the proper AC mains voltage may cause fire and/or internal damage.
Warning: Lethal voltages are present inside the chassis. There are no user serviceable parts inside
the chassis. Refer all service to qualified service personnel or to the factory.
Apply line level audio signal to the input(s). “Line level” means previously amplified audio, i.e. not the output of a micro-
phone or other unamplified audio transducer.
Turn up the INPUT level pot(s) until the red CLIP LED just barely lights. Then back the level down just a bit until the CLIP
LED doesn’t come on any more, or only occasionally flashes.
Now read the rest of this user’s guide.
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Introduction, Fast First Time Setup

User’s Guide
581E Distribution
Amplifier
3/11
Front Panel
Item Description
Input LeveL The four input level controls on the 581E are marked INPUT 1, INPUT 2, INPUT 3 and INPUT 4. Each
control adjusts it’s corresponding input signal over a 30 dB range. With signal applied to input(s) turn up
the INPUT level pot(s) until the red CLIP LED just barely lights. Then back the level down just a bit until the
CLIP LED doesn’t come on any more, or only occasionally flashes. This is the optimum setting and will
provide the greatest signal-to-noise ratio without distortion.
If your incoming signal positions are unpredictable then we suggest a straight up (12 o’clock) setting. Since
the 581E’s input has 18 dB of headroom above +4 dBu, this setting should work well under most conditions.
If you find that your input signal is very low (the output of a “-10” consumer level device, such as a CD
player, for example), turn the INPUT level control clockwise to boost the signal. Conversely, if you’re feeding
a “+8” broadcast level signal to the 581E then turn the INPUT level control counterclockwise until the proper
LED display is achieved.
Input LeDsIndividual LED indicators show input signal levels of -10, 0, +10 and CLIP.
Output LeveL The sixteen output level controls on the 581E are marked OUTPUT 1A, OUTPUT 1B, OUTPUT
1C, OUTPUT 1D, OUTPUT 2A, OUTPUT 2B, etc. Use these controls to attenuate the output level over a
20 dB range. Start by turning all controls fully clockwise (unity gain). This will create equal levels
from all outputs. If for some reason you wish to reduce the level of certain outputs then turn the appropriate
control(s) counterclockwise. Otherwise, for better overall system performance it’s best to leave the controls
wide open (full clockwise) for the hottest possible output signals.
pOwer Red LED indicates power “on”.
Rear Panel
Item Description
IeC COnneCtOr Connect the proper IEC power cable supplied for your locale. Connect only to appropriate AC power source.
Refer to rear panel marking for correct AC source voltage.
Inputs The 581E is fitted with removable terminal blocks for both input and output connections. While not absolutely
necessary, it is usually much easier to unplug the removable block before making or changing connections
The four 581E inputs are balanced. Of course, they may be used in unbalanced configurations but for
optimum system wide performance (best noise rejection) balanced operation is highly recommended,
whenever possible. Be sure and use shielded cable for both input and output connections. The wire should
always be two-conductor plus shield, even for unbalanced connections.
For balanced input signals:
Connect the incoming signal “+” (high) to the “+” INPUT terminal of the 581E.
Connect the incoming signal “-” (low) to the “-” INPUT terminal of the 581E.
Connect the incoming signal ground (shield) to the ground terminal of the 581E. Repeat for all inputs.
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Front & Rear Panel Overview
581E
DISTRIBUTION
AMPLIFIER (4X4)
CHANNEL 1 CHANNEL 2 CHANNEL 3 CHANNEL 4
INPUT 1
CLIP
+10
0
-10
CLIP
+10
0
-10
CLIP
+10
0
-10
CLIP
+10
0
-10
OUTPUT 1A OUTPUT 1B OUTPUT 1C OUTPUT 1D OUTPUT 2A OUTPUT 2B OUTPUT 2C OUTPUT 2D OUTPUT 3A OUTPUT 3B OUTPUT 3C OUTPUT 3D INPUT 4 OUTPUT 4A OUTPUT 4B OUTPUT 4C OUTPUT 4D
POWER
INPUT 3
INPUT 2
MANUFACTURED BY SYMETRIX, INC. MOUNTLAKE TERRACE, WA USATHIS UNIT CONTAINS NO USER SERVICEABLE PARTS.
AC INPUT
18 WATTS MAXIMUM FABRIQUÉ AUX E.-U. PAR SYMETRIX, INC. MOUNTLAKE TERRACE, WA PAS DES ELEMENTS SERVIABLE PAR UTILISATEUR
581E
DISTRIBUTION
AMPLIFIER (4X4)
OUT 4D OUT 4C OUT 4B OUT 4A INPUT 4
CHANNEL 4
OUT 3D OUT 3C OUT 3B OUT 3A INPUT 3
CHANNEL 3
OUT 2D OUT 2C OUT 2B OUT 2A INPUT 2
CHANNEL 2
OUT 1D OUT 1C OUT 1B OUT 1A INPUT 1
CHANNEL 1

User’s Guide
581E Distribution
Amplifier
4/11
Rear Panel Overview... continued
For unbalanced input signals, using two-conductor shielded cables:
Connect the incoming signal “+” (high) to the “+” INPUT terminal of the 581E. Use the red wire.
Connect the incoming signal ground to the “-” INPUT terminal of the 581E. Use the black wire.
Connect the cable shield at the ground connection of the 581E only.
If you experience hum or noise, make sure that both the 581E and the device which you are feeding are
grounded on the same AC mains circuit. If this is not the source of the noise problem, you must isolate the
unbalanced output from the balanced input with an audio transformer or “matchbox.”
WIRING THE 581E IN 2x8 or 1x16 CONFIGURATION
To connect the 581E as a 2 input, 8 output distribution amplifier proceed as follows:
Connect the two incoming signals to INPUT 1 and INPUT 2 as per the instructions above.
Connect (4) additional short pieces of #20 or #22 gauge wire as follows:
INPUT 1 “+” to INPUT 3 “+”
INPUT 1 “-” to INPUT 3 “-”
INPUT 2 “+” to INPUT 4 “+”
INPUT 2 “-” to INPUT 4 “-”
To connect the 581E as a 1 input, 16 output distribution amplifier proceed as follows:
Connect the single incoming signal to INPUT 1 as per the instructions above.
Connect (6) additional short pieces of #20 or #22 gauge wire as follows:
INPUT 1 “+” to INPUT 2 “+”
INPUT 2 “+” to INPUT 3 “+”
INPUT 3 “+” to INPUT 4 “+”
INPUT 1 “-” to INPUT 2 “-”
INPUT 2 “-” to INPUT 3 “-”
INPUT 3 “-” to INPUT 4 “-”
Outputs The 581E’s four outputs are active balanced circuits and should be used to feed balanced audio inputs. Use
two-conductor shielded audio cable for all connections.
Feeding balanced inputs:
Connect the “+” (high) OUTPUT terminal of the 581E to the “+” (high) of the input of the device which you
are feeding.
Connect the “-” (low) OUTPUT terminal of the 581E to the “+” (high) of the input of the device which you
are feeding.
Connect cable shield to the ground of the 581E and the ground connection of the device which you are
feeding.
Feeding unbalanced inputs:
WE DON’T RECOMMEND IT. If you must feed an unbalanced input with the 581E, you should isolate
the two devices with either an audio transformer or an interface matching device (a “matchbox”). The 581E
follows the AES standards for balanced audio circuits. The ground connections of the amplifier are chassis
ground.
If you must connect the output of the 581E directly to an unbalanced input, try this procedure. Use two-
conductor shielded audio cable.
Connect the “+” (high) OUTPUT terminal of the 581E to the “+” (high) of the unbalanced input.
Make no connection to the “-” (low) OUTPUT terminal of the 581E.
Connect the cable shield at the 581E’s ground and at the input connector of the unbalanced input.
The output signal level of the 581E will be 6 dB lower when driving an unbalanced input without a
transformer or matching interface device.
If you experience hum or noise, make sure that both the 581E and the device which you are feeding are
grounded on the same AC mains circuit. If this is not the source of the noise problem, you must isolate the
balanced output from the unbalanced input with an audio transformer or “matchbox.”
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User’s Guide
581E Distribution
Amplifier
5/11
Connecting to Other Gear
Matching Levels vs Matching Impedances
In any audio equipment application, the question of “matching” inevitably comes up. Without digging a hole any deeper than
absolutely necessary, we offer the following discussion to (hopefully) clarify your understanding of the subject.
Over the years, we have all had impedance matching pounded into our heads. This is important only for vintage audio sys-
tems, power amplifiers, and RF. Technically speaking, the reason is power transfer, which reaches a maximum when source
and load are matched. Modern audio systems are voltage transmission systems and source and load matching is not only
unnecessary, but undesirable as well.
Vintage audio systems operate at 600 ohms (or some other impedance value), and must be matched, both at their inputs
and at their outputs. Generally speaking, if you are dealing with equipment that uses vacuum tubes, or was designed prior
to 1970, you should be concerned about matching. These units were designed when audio systems were based on maxi-
mum power transfer, hence the need for input/output matching.
Power amplifiers are fussy because an abnormally low load impedance generally means a visit to the amp hospital. Thus,
it’s important to know what the total impedance of the pile of speakers connected to the amplifier really is.
RF systems are matched because we really are concerned with maximum power transfer and with matching the imped-
ance of the transmission line (keeps nasty things from happening). Video signals (composite, baseband, or otherwise)
should be treated like RF.
Some folks seem to believe that balanced/unbalanced lines and impedances are related; or even worse that they are associ-
ated with a particular type of connector. Not so. Unbalanced signals are not necessarily high-impedance and balanced sig-
nals/lines are not necessarily low-impedance. Similarly, although 1/4 inch jacks are typically used for things like guitars (which
are high-impedance and unbalanced), this does not predispose them to only this usage. After all, 1/4 inch jacks are sometimes
used for loudspeakers, which are anything but high-impedance. Therefore, the presence of 3-pin XLR connectors should not
be construed to mean that the input or output is low-impedance (or high-impedance). The same applies to 1/4 inch jacks.
So, what is really important? Signal level, and (to a much lesser degree), the impedance relation between an output (signal
source) and the input that it connects to (signal receiver).
Signal level is very important. Mismatch causes either loss of headroom or loss of signal-to-noise ratio. Thus, microphone in-
puts should only see signals originating from a microphone, a direct (DI) box, or an output designated microphone-level output.
Electrically, this is in the range of approximately -70 to -20 dBm. Line inputs should only see signals in the -10 to +24 dBm/dBu
range. Guitars, high-impedance microphones, and many electronic keyboards do not qualify as line-level sources.
The impedance relation between outputs and inputs needs to be considered, but only in the following way - Always make sure
that a device’s input impedance is higher than the output source impedance of the device that drives it.
Some manufacturers state a relatively high-impedance figure as the output impedance of their equipment. What they really
mean is that this is the minimum load impedance that they would like their gear to see. In most cases, seeing a output imped-
ance figure of 10,000 (10K) ohms or higher from modern equipment that requires power (batteries or AC) is an instance of this
type of rating. If so, then the input impedance of the succeeding input must be equal to or greater than the output impedance
of the driving device.
Symetrix equipment inputs are designed to bridge the output of whatever device drives the input (i.e. to be greater than 10
times the actual source impedance). Symetrix equipment outputs are designed to drive 600-ohm or higher loads (600-ohm
loads are an archaic practice that won’t go away). You don’t need to terminate the output with a 600-ohm resistor if you aren’t
driving a 600-ohm load. (If you don’t understand the concept of termination, you probably don’t need to anyway.)
The two facts that you need to derive from this discussion are:
Match signal levels for best headroom and signal-to-noise ratio.
For audio, impedance matching is only needed for vintage equipment and power amplifier outputs. In all other cases, en-
sure that your inputs bridge your outputs (meaning the inputs are in the range of 2 to 200 times the output source imped-
ance).
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•
•
•

User’s Guide
581E Distribution
Amplifier
6/11
Connecting to Other Gear... continued
Signal Levels
The 581E is designed around studio/professional line levels: +4 dBu or 1.23 volts RMS. The unit is quiet enough to operate at
lower signal levels such as those found in semi-pro or musical instrument (MI) equipment (-10 dBu or 300 millivolts).
I/O Impedances
The 581E is designed to interface into almost any recording studio or sound reinforcement application. This includes:
600-ohm systems where input and output impedances are matched.
Modern bridging systems where inputs bridge and outputs are low source impedances (voltage transmission systems).
The 581E’s input impedance is greater than 20-kilohms balanced. The inputs may be driven from any balanced source ca-
pable of delivering at least -10 dBu into the aforementioned impedances.
The 581E’s output impedance is 600 ohms balanced, 300 ohms unbalanced. The output line driver delivers +22 dBm into 600-
ohm balanced loads or +18 dBm into 600-ohm unbalanced loads.
Input and Output Connections
The illustration on the next page shows how to connect the 581E to balanced and unbalanced sources and loads.
To operate the 581E from unbalanced sources, run a 2-conductor shielded cable (that’s two conductors plus the shield) from
the source to the 581E. At the source, connect the low/minus side to the shield, these connect to the source’s ground; con-
nect the high/plus side to the source’s signal connection. At the 581E, the high/plus wire connects to pin 2, the low/minus wire
connects to pin 3, and the shield (always) connects to pin 1. This is the preferred method as it makes best use of the 581E’s
balanced input (even though the source is unbalanced). The other alternative shown in the illustration converts the 581E’s
balanced input into an unbalanced input at the input connector. This works, but is more susceptible to hum and buzz than the
preferred method. There is no level difference between either method.
You can drive unbalanced loads with the 581E’s outputs by using the XLR connector with pin 3 left open. In an emergency
(the show must go on), you can ground pin 3, but if you have the choice... leave it open. If you must ground pin 3, it is must be
grounded at the 581E, rather than at the other end of the cable. The price, regardless of whether or not pin 3 is grounded is 6
dB less output level. If your system is wired with pin 3 hot, and you are driving an unbalanced load, pin 2 must float.
•
•

User’s Guide
581E Distribution
Amplifier
7/11
Cabling Examples
(Wire Shield Not Connected)
TS Plug
Tip = High
Sleeve = Shield
TIP
SLEEVE
(When Using CIRCUIT Ground)
(Wire Low Not Connected)
Balanced Male XLR
Pin 2 = High
Pin 3 = Low
Pin 1= Circuit Ground
Shield Tab = Not Connected
(When Using CIRCUIT Ground) Channel
Channel
Output
Two Conductor
Shielded CableShielded Cable
Two Conductor
Shielded Cable
Output
(Wire Shield Not Connected)
RCA Plug
Tip = High
Sleeve = Low
(When Using CIRCUIT Ground)
(Wire Shield Not Connected)
Channel
Input
Shielded Cable
Two Conductor
Shielded Cable
12 3
(When Using CIRCUIT Ground)
(When Using CIRCUIT Ground)
(When Using CIRCUIT Ground)
(When Using CIRCUIT Ground)
Channel
Input
TIP
Tip = High
Sleeve = Low
(Wire Shield Not Connected)
SLEEVE Shielded Cable
Two Conductor
TS Plug
Channel
Input
Channel
Input
TRS Plug
TIP
SLEEVE
RING
Tip = High
Ring = Low
Sleeve = Not Connected
Channel
Input
Two Conductor
Shielded Cable
Balanced Female XLR
Balanced Terminal Strip
Shield Tab = Not Connected
2
Pin 1=Not Connected
1
Pin 2 = High
Pin 3 = Low
3
Shielded Cable
Two Conductor
Shielded Cable
Two Conductor

User’s Guide
581E Distribution
Amplifier
8/11
Block Diagram
CHANNEL 4
CHANNEL 3
CHANNEL 1
CHANNEL 2
Display
Input LED
Channel 1
CLIP
+10
0
-10
Level
Output 1A
Level
Output 1B
Level
Output 1C
Output 1D
Level
1A
OUT
1B
OUT
1C
OUT
1D
OUT
Channel 1
Input
Level
Input 1

User’s Guide
581E Distribution
Amplifier
9/11
Troubleshooting
Troubleshooting Chart
SYMPTOM PROBABLE CAUSE
No output Check cables and connections. Are inputs driven by outputs, and outputs driving inputs? Verify
cables, source and load by patching input and output connections together, at the unit. Check for
AC power presence.
Hum or buzz in output Check input and output connector wiring. Ground loop: check related system equipment
grounding. Are all system components on the same AC ground?
Distortion Check the level of the input signal on the 581E’s LED display(s). Is the CLIP light on all the time?
If so, reduce the incoming signal level by turning the INPUT level counterclockwise. Is the incoming
signal already distorted? Listen “up stream” from the 581E to make sure you’re feeding it a clean
signal.
Noise (hiss) Check input signal levels and input level control settings The input signal may be too low. If so,
boost the incoming signal (if possible). Is the input signal already noisy? Listen “up stream” from
the 581E to determine that you are feeding it a clean signal.
No LED display Is the unit plugged in, and turned on? Is the AC outlet OK?
Notes

User’s Guide
581E Distribution
Amplifier
10/11
Specifications and Declaration of Conformity
Architects and Engineers Specifications
The audio distribution amplifier shall be a four channel unit with each channel consisting of one electronically balanced input amplifier
and four electronically balanced output amplifiers. Associated with each channel shall be a master gain adjustment circuit capable of
up to 15dB of gain or 15dB of loss for the purpose of optimally matching incoming signal level(s). Also associated with each channel
shall be a four LED array for the indication of the signal levels applied to the output drive circuits. The LED’s shall be labelled CLIP,
+10, 0, and -10 corresponding to internal signal levels of +18dBu, +10dBu, 0dBu, and -10dBu.
Each output shall be capable of driving a 600-ohm balanced load to a level of +22 dBm. The maximum output level into a balanced
bridging load (20K Ohms) shall be +26 dBu. Each output will offer an individual attenuator with a range of 0 to -20 dB.
Frequency response through the amplifier shall be ±½ dB, measured between 20 Hz and 20 kHz. THD+Noise shall be less than
0.009% measured at unity gain with a bandwidth of 30 kHz. Residual noise will be >100 dB below a +4 dBu input signal when mea-
sured with an A-weighting filter.
The unit shall occupy one rack space (1U). The physical dimensions shall be 1.72”H x 19”W x 6”D; 4.45cm H x 43.7cm W x 15.24cm
D.
The distribution amplifier shall operate by means of its built-in power supply connected to 117V AC, nominal, 95-130V AC, 50-60 Hz;
or 230V AC nominal, 165-255V AC, 50 Hz. Power consumption shall be 18 watts, maximum. There shall be a rear panel receptacle
for an IEC type detachable power cord. The distribution amplifier shall carry the CE mark.
The distribution amplifier shall be a Symetrix, Inc. model 581E Distribution Amplifier (4x4).
Specifications
Input/Output
Maximum Input Level +26 dBu Balanced
Maximum Output Level +26 dBu Balanced (20k Ohm load)
+22 dBm (600 Ohm load)
Input Impedance 20k Ohms Balanced, 10k Ohms Unbalanced
Output Impedance 200 Ohms Balanced, 100 Ohms Unbalanced
Performance Data
Frequency Response ±½ dB, 20 Hz - 20 kHz
THD+Noise <.009%, unity gain input to output,
30kHz measurement bandwidth
Signal to Noise Ratio >100dB, A-weighted, ref. to +4dBu
Dynamic Range >125 dB, A-weighted
Common Mode Rejection >40 dB, 20 Hz - 20 kHz
Input Gain Range ±15dB
Output Gain Range 0 to -20dB
Physical
Size (hwd) 1.72 x 19 x 6 in., 4.37 x 48.26 x 15.24 cm.
Shipping Weight 8 lbs
Electrical
Power Requirements 117V AC nominal, 95-130V AC, 50-60 Hz
230V AC nominal, 165-255V AC, 50Hz
Power Consumption 18 watts maximum
Note: The maximum operating ambient temperature is
25 degrees C.
Declaration of Conformity
We, Symetrix Incorporated, 6408 216th St. SW, Mountlake Terrace,
Washington, USA, declare under our sole responsibility that the product:
581E Distribution Amplifier
to which this declaration relates, is in conformity with the following
standards:
EN 60065
Safety requirements for mains operated electronic and related
apparatus for household and similar general use.
EN 50081-1
Electromagnetic compatibility - Generic emission standard
Part 1: Residential, commercial, and light industry.
EN 50082-1
Electromagnetic compatibility - Generic immunity standard
Part 1: Residential, commercial, and light industry.
The technical construction file is maintained at:
Symetrix, Inc.
6408 216th St. SW
Mountlake Terrace, WA, 98043 USA
The authorized representative located within the European Community
is:
World Marketing Associates
P.O. Box 100
St. Austell, Cornwall, PL26 6YU, U.K.
Date of issue: October 31, 1998
Place of issue: Lynnwood, Washington, USA
Authorized signature:
Dane Butcher, President, Symetrix Incorporated.

User’s Guide
581E Distribution
Amplifier
11/11
The Symetrix Limited Warranty
Symetrix, Inc. expressly warrants that the product will be free
from defects in material and workmanship for eighteen (18)
months from the date the product is shipped from the factory.
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 workman-
ship within eighteen (18) months from the date the product
is shipped from the factory, 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 determina-
tion 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 warran-
ties, whether oral, written, express, implied or statutory.
Symetrix, Inc. expressly disclaims any IMPLIED warran-
ties, including fitness for a particular purpose or mer-
chantability. Symetrix's warranty obligation and buyer's
remedies hereunder are SOLELY and exclusively as stated
herein.
This Symetrix Lucid product is designed and manufactured
for use in professional and studio audio systems and is not
intended for other usage. With respect to products pur-
chased 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 disclaim-
ers set forth herein, shall extend to the original purchaser and
anyone who purchases the product within the specified war-
ranty period.
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.
Note: Some Symetrix Lucid products contain embedded
software and may also be accompanied by control software
intended to be run on a personal computer. Said software is
specifically excluded from this warranty.
Limitation of Liability
The total liability of Symetrix on any claim, whether in contract,
tort (including negligence) or otherwise arising out of, con-
nected 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 incidental 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,
substitute facilities or supply houses.
Servicing the 581E Distribution Amplifier
If you have determined that your 581E Distribution Amplifier
requires repair services and you live outside of the United
States please contact your local SymNet 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 three (3) years from date of discontinued manufac-
ture.
Before sending anything to Symetrix, please contact our
Customer Service Department for a return authorization (RA)
number. The telephone number is [phone]. Additionally
support is available via the web site:
support.symetrixaudio.com.
In-warranty repairs
To get your 581E Distribution Amplifier repaired under the
terms of the warranty:
1. Call us for an RA number (have the serial number, shipping
and contact information and description of the problem
ready).
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 don't have the factory packaging materials, we rec-
ommend 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. We won't return
the unit in anything but Symetrix packaging for which we will
have to charge you. If the problem is due to operator misuse
or error, you will have to pay for both parts and labor. In any
event, if there are charges for the repair, 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 neces-
sary parts, labor, packaging materials, and freight charges.
Please remember, you must call for an RA number before
sending the unit to Symetrix.
Warranty and Service

6408 216th St. SW, Mountlake Terrace, WA, USA • Tel [phone] • Fax [phone] • Web www.symetrixaudio.com
© 2006, Symetrix, Inc. All rights reserved. Printed in the United States of America. Symetrix Part Number 53581E-1C00. The information in this
User’s Guide is subject to change without notice. Symetrix, Inc. shall not be liable for technical or editorial errors or omissions contained herein; nor
is it liable for incidental or consequential damages resulting from the furnishing, performance, or use of this material. 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 User’s Guide may be reproduced or transmitted in any form or by any
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print one copy is hereby granted. Product names mentioned herein may be trademarks and/or registered trademarks of their respective companies.