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AV25-2 NET
AV25-2 NET+
AV25-2 NET Series
Owner’s Manual
June 2012
www.stewartaudio.com
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Important Safety Instructions
Before using your Stewart Audio Inc. Power Amplier, please read this
Owner’s Manual carefully to ensure optimum trouble-free performance.
WARNING: TO REDUCE THE RISK OF ELECTRICAL SHOCK, DO NOT EX-
POSE THIS AMPLIFIER TO RAIN OR MOISTURE. DANGEROUS HIGH
VOLTAGES ARE PRESENT INSIDE THE ENCLOSURE. DO NOT OPEN THE
CABINET. REFER SERVICING TO QUALIFIED PERSONNEL ONLY.
CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK,
DO NOT REMOVE COVER (OR BACK). NO USER-
SERVICEABLE PARTS INSIDE. REFER SERVICING TO
QUALIFIED SERVICE PERSONNEL.
The lighting bolt within arrowhead symbol, within an
equilateral triangle, is intended to alert the user to the
presence of un-insulated “dangerous voltage” within
the product’s enclosure that may be of sufcient magnitude to constitute a risk of electrical shock to person.
The exclamation point within an equilateral triangle, is
intended to alert the user to the presence of important
operating and maintenance (servicing) instruction in the
literature accompanying the appliance.
Important Safety Instruction – Please Read Prior to Product
Installation.
1. Installation should be performed by a trained and licensed professional to
insure safe and lasting operation.
2. All of the safety and operating instructions should be read before the amplier is installed or operated. Retain these instructions for future reference. All instructions should be followed; all warnings on the amplier
and in the operating instructions should be adhered to.
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
3. The amplier should be situated so that its location and position does not
interfere with its proper ventilation. For example, the amplier must not
be placed on a rug, bed, sofa or similar surface that impedes airow
across the chassis. Airow through the ventilation openings should be
unobstructed.
4. This amplier should not be used near water, for example, near a bathtub,
in a wet basement, near a swimming pool, etc. This amplier is intended
to be operated in a controlled indoor environment.
5. Do not place the amplier near heat sources such as radiators, heat registers, stoves, or other appliances that produce heat.
6. The amplier should only be connected to 120 VAC, 60 Hz power supply.
Do not defeat the ground or polarization of the power plug.
7. Route power cord and other cables so that they are not likely to be
walked on, tripped over or stressed. Pay particular attention to condition
of cords and cables at plugs and at the point where they exit the amplier. To prevent risk of re or injury, damaged cords and cables should be
replaced immediately.
8. Clean the amplier with a clean, damp cloth. Do not use solvents or abrasive cleaners. Never pour any liquid on the amplier.
9. When left unused for a long period of time, the power cord should be
unplugged form the outlet.
10. Damaged Ampliers requiring service should be repaired by a qualied
service technician when:
a. The power cord or AC plug has been damaged.
b. Objects have fallen, or liquid has spilled into the unit.
c. The amplier has been exposed to rain or other moisture.
d. The amplier does not appear to operate normally or exhibits
a marked change in performance.
e. The amplier has been dropped or the enclosure
damaged.
11. The user should not attempt to service the amplier beyond that described in the operating instructions. All other servicing should be referred
to qualied service personnel.
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Table of Contents
Important Safety Instructions ······························································ 2
Table of Contents ················································································ 4
1 Welcome ························································································· 5
1.1 Features ··············································································· 5
1.2 Using this Manual ································································ 5
2 Setup ······························································································· 6
2.1 Setup Precautions ······························································· 6
2.2 Amplier Installation ···························································· 6
2.3 Proper Cooling Considerations ············································ 8
2.4 Input Connections ······························································· 9
2.5 Output Connections ·························································· 12
3 Operation ····················································································· 13
3.1 Operation Precautions ······················································· 13
3.2 Controls, Indicators, and Connectors ································ 14
3.3 CobraNet ··········································································· 17
3.4 Remote Volume Control ··················································· 20
4 Troubleshooting ·········································································· 21
5 Technical Specications ····························································· 22
6 Warranty Information ·································································· 23
6.1 Warranty Summary ··························································· 23
6.2 Return Procedure ····························································· 23
7 Accessories ·················································································· 26
8 Notes ····························································································· 27
1 Welcome
Congratulations on the purchase of your new Stewart Audio AV Series
power amplier. This amplier has been designed and built to provide
you with years of high-quality audio performance and trouble-free operation. If after reading this manual you should have any questions concerning amplier installation and operation, please contact your Authorized Stewart Dealer, or you may contact us directly using the contact
information provided on the back of this manual.
1.1 Features
Your Stewart Audio AV Series amplier is the result of years of
experience in the design and manufacture of quality ampliers. As such
it provides a combination of performance and operational benets that
simply cannot be found in conventional ampliers.
Sub Compact 1/4 rack package
Two channel CobraNet amplier, optimized to drive 4
Ohm and 8 Ohm loads
Selectable priority switching on NET+ models
Clean full–range dynamic power
Signal Detect trigger for sleep & wake up
Multiple mounting options
Made in the USA
1.2 Using this Manual
In order to obtain maximum performance from your AV Series Amplier, please take time to read this brief owner’s manual and carefully follow the guidelines for connection and operation.
This manual provides you with the information necessary to safely install and operate your new AV Series amplier in the most common
scenarios. If you nd yourself requiring additional assistance, please
feel free to contact your Authorized Dealer, or you may contact us directly using the contact information provided on the back of this manual.
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2 Setup
2.1 Setup Precautions
CAUTION: Before installing your amplier, make sure that
you have read the Important Safety Precautions at the beginning of this manual.
2.2 Amplier Installation
The AV25-2 NET+ incorporates a number of different mounting options
in order to t your installation needs.
2.2.1 Pole-Mounting
The AV Series of ampliers is Stewart Audio’s rst line of polemountable ampliers. The AV25-2 NET+ has mount holes on both the
top as well as the side of the unit which can be used with the AV-Pole
bracket available from Stewart Audio.
Part Number: AV-Pole
2.2.1 Universal-Mount Installation
The AV25-2 NET+ also has a universal bracket available which allows
the unit to be mounted against a wall or under a table. Two screws are
included in the kit which will afx the bracket to the top or the side of
the unit. Once this is done, two holes are available for mounting the
unit where desired.
CAUTION: Use only the screws provided in mounting
brackets to the amplier. Do not over tighten.
Part Number: AV-Bracket
AV25-2 NET+
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2.2.3 Product Dimensions
6.00in
15.3cm
AV25-2 NET+
Front
4.00in
10.2cm
1.25in
3.2cm
2.4 Input Connections (NET+ Model Only)
Your AV25-2 NET+ amplier is provided with a 3-pin Phoenix connector
for each input. This connector will accept both balanced or unbalanced
connections, however some modications must be made for an unbalanced connection. See the next two sections for instructions on connecting your amplier to its input source.
2.4.1 Balanced Connections
When using a balanced input source and connector, you must ensure
that the hot, cold, and ground pins of the connector are matched up to
the +, -, and ground pins of the AV25-2 NET+’s Phoenix connector respectively. Diagrams have been provided for standard XLR and TRS
connectors. Please refer to the manual of your input source in case it
does not follow the standard pin-out.
1.25in
3.2cm
Side
2.3 Proper Cooling Considerations
Because the AV25-2 NET+ regulates its temperature using convection
cooling and no fans, the amplier must be given adequate space to
allow for proper airow. Do not stack the ampliers on top of each other or mount it in a way that other equipment will block airow through
the case.
CAUTION: Inadequate airow to the amplier can cause the
amplier to overheat and potentially become damaged in
the process. Be sure to provide plenty of air space to allow
for convection cooling.
Input Connector
-
+
-
+
Female XLR
Input Connector
-
+
-
+
-
Male TRS
+
+
Ground
(Shield)
(Connector enlarged to show detail)
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2.4.2 Unbalanced Input Connections
When using an unbalanced input source and connector, a jumper must
be added between the negative (-) terminals and the ground terminals.
Once this has been done, the unbalanced source can be connected to
the positive (+) and ground terminals. Please refer to the manual of
your input source in case it does not follow the standard pin-out. For
your convenience, pre-wired connectors are available for purchase, see
the next page for details.
NOTE: A jumper is required for connecting an unbalanced
input.
Pre-wired unbalanced connectors are available for purchase from Stewart Audio. These will allow for a quicker installation with less room for
error when connecting the CVA Series amplier to an unbalanced
source. The summing adapters will properly sum a stereo source for
use with the mono input on the rear of the amplier without causing
sound cancellation. Part numbers are found below the diagrams.
ADPT-RCA
Mono
Female RCA
ADPT-SUMRCA
Stereo
Female RCA
ADPT-SUM35
Stereo
Female 3.5mm
NOTE: The CVA Series of ampliers do not accept stereo
inputs. Either one side must be selected from the stereo
source or an overload-protected Y-cable must be used to
sum them to mono. It is highly recommended that you
purchase the pre-wired connectors mentioned on the next
page. Damage to source equipment can result from the
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2.5 Output Connections
Stewart Audio recommends using high-quality, heavy-gauge speaker
wire and connectors to send the output signal of your amplier to the
speakers. Use the following table as a guideline when selecting your
wire gauge.
Speaker leads connect by means of terminal block connectors supplied
with the unit. Strip speaker leads 1/4” and insert into connector observing proper polarity. With a small, at-blade screwdriver, tighten the
screw until the leads are held securely in place. Inspect for possible
shorts or broken wires.
Channel 2
+
Distance Wire Gauge
Up to 25 ft. 16 AWG
26-40 ft. 14 AWG
41-60 ft. 12 AWG
Terminal Block Connector
(Rear of AV25-2 NET)
+ - +
-
-
Channel 1
+
-
3 Operation
3.1 Operating Precautions
1. Before use, your amplier must be congure for proper operation,
including input and output wiring hookup. Improper wiring can result in damage to equipment or potentially harm to the operator.
Consult section 2 for setup instructions.
2. Tampering with the circuitry, or making unauthorized changes is
not only dangerous but may also violate local regulations.
3. Use care when making connections between the amplier and the
input or output equipment. Using equipment that is not capable of
handling the output wattage may lead to permanent damage.
NOTE: Stewart Audio will not be held responsible for
damage to your AV25-2 NET+ or connected equipment if
the instructions in this manual are not followed.
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3.2 Controls, Indicators, and Connectors
1
2
3
6 7 8
4
5
1
2
3
6
7
8
4
5
9
11
12
109
11
12
10
1
2 3
1
2
3
4
5
6
4 5
6
AV25-2 NET+
LEVEL
COBRANET
NET LOC
PRIORITY
1
Signal Priority Switch
CobraNet Connector
Channel 2 Level Knob
Channel 1 Level Knob
Input Connector
Line Out
2
+ - + -
1
+ +
+10V
RVC
GND
MUTE
SIG PWR #2 CLIP #1
RVC#2 LINE OUT #1#2 LOCAL IN #1
10
Remote Volume Control
Signal Present Indicator LED
Power Indicator LED
Clip Indicator LEDs
10
Power Connector
11
Speaker Out Connector
12
PWR
11
- +
#2 Speaker #1
12
- + - +
AV25-2 NET
COBRANET
1
CobraNet Connector
Line Out
Signal Present Indicator LED
+ +
- +
SIG PWR
Power Indicator LED
Power Connector
Speaker Out Connector
PWR#2 LINE OUT #1
#2 Speaker #1
- + - +
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3.2.1 Indicators
The AV25-2 NET series has up to 4 rear panel LED indicators. The rst
is the power indicator which will illuminate when power is supplied to
the amplier. The second light is the signal present LED which will illuminate when signal is detected on either one of the input connection
channels. The nal 2 LED indicators (only on the NET+ models) are the
“Clip” indicators, one for each channel. These lights will indicate that
the input signal is too “hot” and will sound distorted when amplied.
To x this, the gain should be reduced at the preamp or mixer level.
3.2.2 Controls (NET+ Models Only)
All AV25-2 NET+ controls are located on the rear of the unit. There is
no power switch so the AV25-2 NET+ will turn on whenever power is
supplied to it. Signal Sense Technology (SST ) will power up the amplier from sleep when a signal is detected. After 5 minutes without an
input signal the amplier will go into sleep mode.
The rear panel contains two individual channel volume knobs . The amplier is set to run off of a line-level source and the level should be adjusted for optimum performance. To adjust this knob, you will need a
small at-head screwdriver. While a typical program source level is
present, spin the rotary knob as far clockwise as you can without hearing distortion or without the “Clip” indicator illuminating. If the signal is
distorting and the knob is all the way counter-clockwise, adjust the gain
down at the source level.
3.2.3 Signal Priority Switching (NET+ Models Only)
The AV25-2 NET+ amplier includes selectable priority switching which
allows either the network or local input to override the other depending
on the conguration. The switch located on the rear of the amplier
allows the operator to select the priority input. When audio is detected
on the priority input the amplier will cut the signal from the secondary
input. An example scenario is in a paging situation where a network
signal would override a local audio input.
3.3 CobraNet
3.3.1 CobraNet FAQ
Q: How do CobraNet devices communicate on the network? Do they
receive an IP address?
A: CobraNet devices operate without the need for an IP address. Many
conguration applications for CobraNet devices will assign an IP address for organizational purposes. However, CobraNet devices operate
using data channels called “bundles”. In order to connect a transmitter
and a receiver in a CobraNet network, both devices simply need to be
set to the same bundle number. There is no need for a DHCP server (a
router for example).
Q: How do I congure the bundles of the AV25-2 NET+?
A: Bundle settings should be congured using Cirrus Logic’s CobraNet
Discovery Utility. Instructions for downloading and operation can be
found in section 3.3.2.
Q: Why is the CobraNet Discovery Utility not detecting any devices?
A: First, ensure that your computer has an IP address. If you are operating without a DHCP server (ie in a switch-only network) then you will
need to manually set an IP address in the Network Conguration section of Windows. Next, go to Tools > Options in the top menu and
make sure the proper network device is selected in the top dropdown.
Q: Can the AV25-2 NET+ transmit the input channels to other CobraNet
devices?
A: No, the AV25-2 NET+ is designed only to receive audio .
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Q: What submap channels do the AV25-2 NET+ use?
A: Since the AV25-2 NET+ is a 2-channel device, only the rst two submap channels are valid (channels 1 and 2). Data sent on channels 3-8
will be ignored.
3.3.2 Using CobraNet Discovery Utility
The CobraNet Discovery utility can be downloaded from the Cirrus Logic website at: http://www.cobranet.info/downloads/disco
Once installed, it should be launched from a computer on the same
network as the AV25-2 NET+. After the program launches it will search
for CobraNet devices. The AV25-2 NET+ will appear as “Attero Tech
CobraNet CEP2224”. If this is the rst time you are setting up this device, or the device has been power cycled, the IP address will appear
as 0.0.0.0. To set an IP address for easier recognition, right-click the
device and select “Update IP Address”. To ensure visibility, assign it to
the same subnet as the computer you are conguring it from.
Rx #1 and Rx #2 directly correspond to Channel 1 and Channel 2 of the
amplier.
3.3.2 Setting Up Bundles
To open up the bundle conguration window, double-click on the device listed in the screen above. You will see 2 Tx and 2 Rx bundles
ready to congure. Do not congure the two Tx bundles. Single-click on
each of the Rx bundles (shown as 300 and 301 in the screen capture
on the next page) to make the elds editable. From here you can enter
a new bundle numbers.
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3.4 Remote Volume Control (NET+ Models Only)
AV25-2 NET+ ampliers can have their volume remotely controlled (or
muted) via the Euro Block input on the rear of the amplier. The remote
volume control allows the units volume to be controlled through the
use of an external potentiometer which can be located wherever convenient for the user. Remote muting is also useful for re-alarm situations in which all unnecessary sound must be silenced.
NOTE: If the remote volume control connector is utilized,
it will override the volume knob on the rear of the unit.
In order to remotely control the volume of the unit, a 10k-ohm potentiometer should be placed between the +10V pin and the GND (Ground)
pin on the rear of the unit with its wiper on the RVC pin. The volume
will be determined by the selected resistance on the potentiometer,
the greater the resistance the louder the volume.
The amplier can be remotely muted by making a connection between
the GND pin and the MUTE pin. No power should be applied to these
pins, simply a contact connection.
4 Troubleshooting
Problem: Power indicator does not turn on.
Procedure: Check that the amplier is plugged into a live outlet. After
you have ensured that it is not a power issue, disconnect any speakers.
If the amplier turns on after a few seconds delay, then the problem is
in the output connection. Check wiring and speakers for short circuits.
Problem: No output on one or both channels; Power indicator is
lit.
Procedure: Check that level controls are not turned down. Check that
input and output connections are secure. Ensure signal present LED is
ashing to denote a signal. If there is no signal detected check signal
source and that level controls are set high enough.
Problem: Amplier overheats and/or shuts off.
Procedure: Review section 2.3 on proper cooling procedures. Check
the signal lights on the rear of the amplier to see if the signal is overdriving (the signal light ashes red frequently). Overdriving the amplier
for extended periods of time can cause a thermal shutdown.
Problem: Output sound is distorted or cracking.
Procedure: Check all cables for damage or loose connections and re-
duce the gain on the input signal at the mixer or preamp level. Replace
the cables and loudspeakers temporarily to see if this resolves the
problem. If problem still exists, contact your Authorized Dealer for service.
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5 Technical Specications
Maximum Output 30Hz - 20kHz
Stereo 25W @ 8Ω per channel
35W @ 4Ω per channel
Frequency Response (+0, -3 dB) 30Hz-20kHz
Bandwidth +/- 3.0dB 30Hz-30kHz
THD+N <0.1%
Signal to noise ratio >100dB
Remote Volume Control 0-10V DC, 4 Pin Euro
Block
External Mute 5-12VDC
Slew Rate 30V/ms
Input Sensitivity 0.5V (-3 dBV)
Standard Voltage Gain 28X (26.5dB)
Input Impedance (Balance/Unbalanced) 20k Ohms/10k Ohms
Sleep, Idle Current Draw, 1/8 Draw 3.3 / 6.9 / 14.2 Watts
Class D
Input Connectors RJ45, Euro Block (NET+)
Output Connectors Euro Block
Power Supply External In-Line 48VDC
Cooling Convection-Cooling
Controls Level (NET+)
LED Indicators Power, Signal Present &
Clip
Construction Aluminum Chassis
Dimensions
Height 1.25in (3.2cm)
Width 6in(15.2cm)
Depth 4in (10.2cm)
Weight 0.57lbs (0.26kg)
Stewart Audio reserves the rate to change features and specications without notice.
6 Warranty Information
6.1 Warranty Summary
All Stewart Audio ampliers and accessories, unless excluded in this
summary, are covered by a 3-year limited warranty on parts and labor
from the data of purchase. In order to be eligible for warranty repairs,
the ampliers and accessories must have been purchased through an
authorized Stewart Audio dealer and submitted by the original purchaser. This warranty is only valid in the country in which the amplier was
purchased.
6.1.1 Eligibility Requirements.
Stewart Audio warrants against all malfunctions which come as a result
of component or manufacturer defect. The amplier is also covered
from all failures which arise during the warranty period (3 years from
date of purchase) that are not a result of misuse. The following actions
will void your warranty:
The power cord or AC plug has been damaged through misuse.
The amplier has been exposed to moisture or extreme tempera-
tures.
The amplier has been dropped, items have been dropped on the
amplier, or the enclosure has been damaged.
The amplier has been opened by the operator.
The amplier was improperly packaged when sending to the fac-
tory for repair, resulting in damage.
Any of the precautions or instructions found in this manual were
not followed.
Damages resulting to the amplier which are not covered under this
warranty can be factory-repaired at cost to the customer. Use the contact information below to initiate the repair process.
6.2 Return Procedure
This section includes the return procedures which must be followed in
order to prevent processing delay or cost to the customer. Please read
the entire section before contacting Stewart Audio for returns.
Page 13
6.2.1 Return Authorization Number
All returns to the factory for service must be accompanied by a Return
Authorization (RA) number. One can be obtained by contacting Stewart
Audio at (209) 588-8111 or via e-mail at support@stewartaudio.com.
NOTE: Any defective products received without an RA number
will be returned to sender at their expense.
If Stewart Audio is unable to contact the sender in 14 days, the merchandise will be considered scrap and may be disposed of.
6.2.2 Shipment Instructions
If Stewart Audio requests that you ship the defective product back to
their service center, please refer to the guide below. To ensure prompt
warranty service, be sure to follow all instructions.
1. Return Authorization (RA) is required for product being sent to the
factory for service.
2. See packing instructions in section 6.2.3.
3. Ship the defective product using a method which provides for order tracking or order conrmation. The service center is located at
the following address:
Stewart Audio
14397 Cuesta Court Suite D1
Sonora, CA 95370
4. Use a bold black marker and write the RA number on three sides
of the box.
5. Record the RMA number for future reference. The RA number can
be used to check the repair status.
6.2.3 Packaging Instructions
Should Stewart Audio request that you ship your product to their service center, these instructions must be followed in order to ensure safe
delivery. If they are not followed, Stewart Audio assumes no responsibility for damaged goods and/or accessories that are sent with your
unit.
6.2.3 Packaging Instructions (cont.)
1. Please write the RA number on three sides of the box. Include the
Stewart Audio RA number inside the box and a brief description of
the problem.
2. Do not ship any accessories (manuals, cords, hardware, etc.) with
your unit. These items are not needed to service your product.
Stewart Audio will not be held responsible for these items if they
are returned with the ampliers.
3. When shipping your amplier, it is important that it has adequate
protection. We recommend you use the original packing material
when returning the product for repair. If you do not have the original box, see number 4.
4. If you provide your own shipping pack, the minimum recommended requirements for materials are as follows:
a. 275 P.S.I. burst test, Double-Wall carton that allows for 2-
inch solid Styrofoam on all six sides of unit or 3 inches of
plastic bubble wrap on all six sides of unit.
b. Securely seal the package with an adequate carton sealing
tape.
c. Do not use light boxes or “peanuts”.
NOTE: Damage caused by poor packaging will not be covered
under warranty.
6.2.4 Estimate Approval
An estimate for all non-warranty repairs will be provided to the customer once the unit has been shipped to the factory. The customer is responsible to approve this estimate within 7 days. If the repairs are not
approved within 14 days, Stewart Audio reserves the right to consider
the unit scrap and may discard it.
6.2.5 Payment of Non-Warranty Repairs
Payment for non-warranty repairs must be submitted to Stewart Audio
before the product will be returned to the customer.
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7 Accessories
The following accessories are available from Stewart Audio for your
amplier.
All part numbers shown are Stewart Audio Part Numbers.
Mounting Brackets
AV-POLE Pole-mount bracket for AV Series ampliers
8 Notes
AV-BRACKET Universal mounting bracket for AV Series ampliers
Connection Adapters
ADPT-RCA Mono Female RCA to male Euroblock.
ADPT-SUMRCA Stereo Female RCA to male Euroblock.
ADPT-SUM35 Stereo Female 3.5mm to male Euroblock
Wall Plates
WP-RVC-B Wallplate with 10k potentiometer and knob for re-
mote volume control (Black)
WP-RVC-A Wallplate with 10k potentiometer and knob for re-
mote volume control (Aluminum)
To purchase these accessories or to see the full
Stewart Audio product lineup, visit us at:
www.stewartaudio.com
For Your Record
In the spaces provided below, record the model and serial
number located at the rear of your amplier.
Model No. ________________________________________
Serial No. _________________________________________
Purchase Date _____________________________________
Retain this information for future reference.
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