Page 1
CVA50-1 NET Series
Owner’s Manual
June 2012
www.stewartaudio.com
CVA50-1 NET
CVA50-1 NET+
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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.
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 am-
plier 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.
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 around the unit 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’s power supply should only be connected to 120 VAC, 60
Hz power source. 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 from 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 1 Welcome
Congratulations on the purchase of your new Stewart Audio CVA 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 CVA 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
CobraNet for two channels of net work audio
Mono constant voltage amplier (100V or 70.7V)
Selectable priority switching (NET+ only)
Remote volume control (NET+ only)
Multiple mounting options
External inline power supply
Made in the USA
1.2 Using this Manual
In order to obtain maximum performance from your CVA 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 CVA 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.
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
2.2.1 Pole-Mount Installation ··········································· 6
2.2.2 Universal-Mount Installation ·································· 7
2.2.3 Product Dimensions ·············································· 8
2.3 Proper Cooling Considerations ··········································· 8
2.4 Input Connections ······························································ 9
2.4.1 Balanced Input Connections ·································· 9
2.4.2 Unbalanced Input Connections ···························· 10
2.5 Output Connections ·························································· 11
2.5.1 Constant Voltage ················································· 11
2.5.2 Wiring Example ···················································· 12
3 Operation ····················································································· 13
3.1 Operation Precautions ······················································· 13
3.2 Controls, Indicators, and Connectors ································ 14
3.2.1 Indicators ······························································ 16
3.2.2 Controls ································································ 16
3.2.3 Remote Volume Control ······································ 17
3.2.4 Signal Priority Switching ······································ 17
3.3 CobraNet ·········································································· 18
4 Troubleshooting ·········································································· 21
5 Technical Specications ····························································· 22
6 Warranty Information ·································································· 23
6.1 Warranty Summary ··························································· 23
6.1.1 Eligibility for Factory Repair ·································· 23
6.2 Return Procedure ····························································· 23
6.2.1 Return Authorization ············································· 24
6.2.2 Packaging Instructions ·········································· 24
6.2.3 Shipping Instructions ············································ 24
6.2.4 Estimate Approval ················································· 25
6.2.5 Payment of Non-Warranty Repair ························ 25
7 Accessories ·················································································· 26
8 Notes ···························································································· 27
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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 CVA Series incorporates a number of different mounting options in
order to t your installation needs.
2.2.1 Pole-Mount Installation
The CVA Series amplier casing 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. Two screws are included in the kit which
will afx the bracket to the top or side of the unit.
2.2.1 Universal-Mount Installation
The CVA Series 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 overtighten.
CVA50-1 NET+
Part Number: AV-Pole
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2.2.3 Product Dimensions
2.3 Proper Cooling Considerations
Because CVA Series ampliers regulates their temperature using convection cooling and no fans, the ampliers 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
along the surfaces of 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.
2.4 Input Connections (NET+ Models Only)
Your CVA Series amplier is provided with a 3-pin Euro Block connector
for its input connection. 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 Input 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 CVA Series’ Euro Block 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.
NOTE: The CVA Series of ampliers do not accept TRS inputs wired for a stereo source. TRS inputs should only be
used for balanced mono inputs.
CVA50-1 NET+
6.00in
15.3cm
1.25in
3.2cm
1.25in
3.2cm
4.00in
10.2cm
Front
Side
Page 6
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.
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
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.
2.5 Output Connections
Because of the differences in the way that constant-voltage ampliers
work as opposed to a typical 8-ohm setup, the wiring procedure and
the gauge of wire used is very different.
Constant voltage systems and speakers use a smaller current ow than
the typical 8ohm systems and thus can use a higher gauge (thinner
diameter) wire. Please refer to the following g chart to choose the appropriate wire gauge for your installation.
Speaker leads connect by means of removable Euro Block connectors
supplied with the unit. Strip speaker leads 1/4” and insert leads 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.
Distance Wire Gauge
Up to 500ft 22 AWG
500-1000 ft. 20 AWG
Over 1000ft 18 AWG
ADPT-RCA
Mono
Female RCA
ADPT-SUMRCA
Stereo
Female RCA
ADPT-SUM35
Stereo
Female 3.5mm
Page 7
3 Operation
3.1 Operating Precautions
1. Before use, your amplier must be congured 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 CVA Series amplier or connected equipment if the instructions in this manual are not followed.
NOTE: For additional operating precautions, please refer
to “Important Safety Instructions” located on Page 2.
2.5.1 Constant Voltage
The Euro Block connector on the rear of the amplier is capable of supplying output at either 100V or 70V depending on the step-down transformers which will be used in the speaker installation. For information
on specic step-down transformer installation information, please consult the transformer’s manufacturer’s literature.
2.5.2 Wiring Example
The diagram below is a typical wiring setup for two speakers with outboard step-down transformers wired in parallel to the 70V output option of a CVA Series amplier.
100V 70V
Page 8
3.2 Controls, Indicators, and Connectors
CVA50-1 NET
COBRANET
OUTPUT
- +
PWRLINE OUT
SIG PWR
+
100V 70V
1
1
2 3
1
CobraNet Connector
2
Line Out
3
Signal Present Indicator LED
4
Power Indicator LED
5
Power Connector
4 5
6
6
Speaker Out Connector
CVA50-1 NET+
COBRANET
PRIORITY
NET LOC
OUTPUT
- +
PWR
+10V
RVC
GND
MUTE
RVCLINE OUTLOCAL IN
+ -
SIG PWR CLIP
+
LEVEL
100V 70V
1
1
2
3
5 6 7
4
1
Signal Priority Switch
2
CobraNet Connector
3
Channel Level Knob
5
Line Out
6
Remote Volume Control
7
Signal Present Indicator LED
4
Input Connector
8
Power Indicator LED
98
10
10
11
11
9
Clip Indicator LEDs
10
10
Power Connector
11
11
Speaker Out Connector
Page 9
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 CVA50-1 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 CVA50-1 NET+ transmit the input channels to other CobraNet devices?
A: No, the CVA50-1 NET+ is designed only to receive audio .
Q: What submap channels do the CVA50-1 NET+ use?
A: Since the CVA50-1 NET+ is a 2-channel device, only the rst two
submap channels are valid (channels 1 and 2). Data sent on channels 38 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 CVA50-1 NET+. After the program launches it will
search for CobraNet devices. The CVA50-1 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.
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.
Page 10
4 Troubleshooting
Problem: Power indicator does not turn on.
Procedure: Check that the unit’s power supply is plugged into a func-
tioning outlet and the power supply is correctly connected to the unit.
Ensure that there is an audio signal present on the audio input indicated
by the green LED being lit. If the unit is powered up but in sleep mode
(due to no signal), the blue power LED will not be lit.
Problem: No output heard on speakers; Blue 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
lit 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 clip LED 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.
Rx #1 and Rx #2 directly correspond to Channel 1 and Channel 2 of the
amplier.
Page 11
5 Technical Specications 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.
Maximum Output 30Hz - 20kHz
CVA-50 50W @ 100V/70V
Frequency Response (+0, -3 dB) 100Hz—20kHz
Power Bandwidth +/- 3dB 80Hz-30kHz
THD+N <0.1%
Signal-to-Noise Ratio >80dB
Remote Volume Control 0-10V DC, 4-pin Block
Input Sensitivity .5V (-3 dBV)
Standard Voltage Gain 151X (43dB) @ 70.7V
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 3-pin,
3.5mm (NET+)
Output Connectors Euro Block 2-pin, 5mm
Power Supply External In-Line 48DVC
Cooling Convection-Cooling
Controls Level
LED Indicators Power, Signal, Clip
Construction Aluminum Chassis
Plenum Rating UL 2043 Approved
Dimensions
Height 1.25in (3.2cm)
Width 4.00in (10.2cm)
Depth 6.00in (15.2cm)
Weight 1.2 lbs (0.54kg)
Stewart Audio reserves the rate to change features and specications without notice.
Page 12
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.
Page 13
8 Notes
For Your Record
In the spaces provided below, record the model and serial
number located at the rear of your amplier.
Retain this information for future reference.
Model No. ________________________________________
Serial No. _________________________________________
Purchase Date _____________________________________
7 Accessories
The following accessories are available from Stewart Audio for your
amplier.
All part numbers shown are Stewart Audio Part Numbers.
To purchase these accessories or to see the full
Stewart Audio product lineup, visit us at:
www.stewartaudio.com
Mounting Brackets
AV-POLE Pole-mount bracket for AV Series ampliers
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
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)
Wall Plates
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