Crown Audio 133472-1A User Manual
1
Amplifi er Application Guide
© 2006 by Crown Audio® Inc., 1718 W. Mishawaka Rd., Elkhart, IN 46517-9439 U.S.A.
Telephone: 574-294-8000. Fax: 574-294-8329.
www.crownaudio.com
Trademark Notice: Amcron®, BCA®, and Crown®, Crown Audio, IOC®, IQ System®, ODEP® and
VZ® are registered trademarks and Grounded Bridge™, PIP™ and PIP2™ are trademarks of
Crown Audio, Inc.
Other trademarks are the property of their respective owners.
Amplifi er Application Guide
133472-1A
1/06
2
The information furnished in this manual does not include all of the details of design, production, or
variations of the equipment. Nor does it cover every possible situation which may arise during installation, operation or maintenance. If you need special assistance beyond the scope of this manual, please
contact our Technical Support Group.
Crown Technical Support Group
1718 W. Mishawaka Rd., Elkhart, Indiana 46517 U.S.A.
DANGER: This amplifi er can produce lethal levels of output power! Be very
careful when making connections. Do not attempt to change the output
wiring unless AC power has been removed from the amplifi er for at least
WARNING: This unit is capable of producing very high sound pressure levels.
Continuous exposure to high sound pressure levels can cause permanent
hearing impairment or loss. Caution is advised and ear protection recommended when playing at high volumes.
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.
6) Clean only with a dry cloth.
7) Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
8) Do not install near any heat sources such as radiators,
heat registers, stoves, or other apparatus that produce
heat.
9) 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 is provided for your safety. If the
provided plug does not fi t into your outlet, consult an
electrician 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 a cart, stand, bracket, or table specifi ed
by the manufacturer, or sold with the apparatus. When a
cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.
13) Unplug this apparatus during lightning storms or
when unused for long periods of time.
14) Refer all servicing to qualifi ed service personnel. Servicing is required when the apparatus has been damaged
in any way, such as power-supply cord or plug 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.
TO PREVENT ELECTRIC SHOCK DO
NOT REMOVE TOP OR BOTTOM COVERS.
NO USER SERVICEABLE PARTS
INSIDE. REFER SERVICING TO QUALIFIED
SERVICE PERSONNEL.
À PRÉVENIR LE CHOC ÉLECTRIQUE
N’ENLEVEZ PAS LES COUVERCLES. IL
N’Y A PAS DES PARTIES SERVICEABLE
À L’INTÉRIEUR. TOUS REPARATIONS
DOIT ETRE FAIRE PAR PERSONNEL
QUALIFIÉ SEULMENT.
The lightning bolt
triangle is used to alert
the user to the risk of
electric shock.
The exclamation point
triangle is used to alert
the user to important
operating or mainte-
Amplifi er Application Guide
Amplifi er Application Guide
3
Table of Contents
Introduction .................................................................................................. 4
Chapter 1: Crown Amplifi ers In-Depth ....................................................... 5
1.1 Rack Cooling ..................................................................................... 5
1.1.1 Fan-Assisted Models ................................................................. 5
1.1.2 Convection-Only Models ........................................................... 6
1.2 System Wiring ................................................................................... 7
1.2.1 Input Wiring ............................................................................... 7
Input Connector Wiring ................................................................. 7
Balanced, Grounded Source ........................................................ 7
Balanced, Floating Source ........................................................... 7
Unbalanced, Grounded Source, Twin-Lead Shielded Cable ......... 8
Unbalanced, Floating Source, Twin-Lead Shielded Cable ............ 8
Unbalanced, Grounded Source, Single-Conductor
Coax or Twisted-Pair Cable ......................................................... 8
Unbalanced, Floating Source, Single-Conductor
Coax or Twisted-Pair Cable ......................................................... 8
1.2.2 Solving Input Problems ............................................................. 9
1.3 Output Wiring .................................................................................. 10
1.3.1 Output Connector Wiring ......................................................... 10
5-Way Binding Post ..................................................................... 10
Barrier Block ................................................................................ 11
®
Neutrik
1.3.2 Amplifi er Load Impedance ..................................................... 13
1.3.3 Determining Appropriate Speaker Wire Gauge ....................... 14
1.3.4 Loudspeaker Protection .......................................................... 15
1.3.5 Solving Output Problems ........................................................ 16
High-Frequency Oscillations ....................................................... 16
Sub-Sonic Currents ..................................................................... 16
1.3.6 Distributed Speaker Systems .................................................. 17
What is Constant Voltage? .......................................................... 17
Transformer Saturation ................................................................ 17
1.4 Multi-way Systems (with Expansion Modules) ................................ 18
1.4.1 Active vs. Passive Crossover Networks .................................. 18
1.5 Fault Monitoring .............................................................................. 20
1.6 Setting System Gain Structure ........................................................ 21
1.6.1 System Levels ......................................................................... 21
1.6.2 Amplifi er Level ......................................................................... 21
Chapter 2: Troubleshooting ......................................................................23
2.1 No Power ......................................................................................... 24
2.2 No Sound ........................................................................................ 25
2.3 Bad Sound ...................................................................................... 26
2.4 Amp Overheating ............................................................................ 26
Chapter 3: Glossary of Terms ...................................................................27
Appendix: Suggested Reading ...............................................................33
Speakon® ...................................................................... 11
Amplifi er Application Guide
4
Introduction
This application guide provides useful information designed to help you best
use your new Crown® amplifi er. It is designed to complement your amplifi er’s
Operation Manual, which describes the specifi c features and specifi cations
of your amplifi er. Helpful guides and tips on subjects such as system wiring
and system gain structure, for example, should be helpful to you whether you
are a beginner or a seasoned professional. You can choose to read this guide
from cover to cover, or if you are already familiar with Crown amps, you can
jump to specifi c sections as needed. A glossary of terms and list of suggested
publications for further reading are also provided for your convenience.
Please be sure to read all instructions, warnings and cautions.
For your protection, please send in the warranty registration card today. And
save your bill of sale—it’s your offi cial proof of purchase.
Amplifi er Application Guide
Chapter 1: Crown Amplifi ers In-Depth 5
Chapter 1
Crown Amplifi ers In-Depth
In This Chapter
• Rack Cooling
• System Wiring
• Amplifi er Load Impedance
• Multi-Way Systems
• Distributed Speaker Systems
• Setting System Gain Structure
Figure 1.1
Top View of RackMounted Amplifi er with
Side Vents
his chapter provides information to help you get optimum performance
from your Crown amplifi er. It is a collection of techniques that can help
T
you avoid many of the common problems that plague sound systems. For
further study on many of these topics, refer to the recommended publications
listed in the Appendix.
1.1 Rack Cooling
When installing your Crown amp in a rack, you should take steps to make
sure that the temperature of the rack stays in a safe range. Crown amps with
fan-assisted cooling and convection-only cooling may require different tech-
niques for best performance.
When designing your rack
cooling system, you should
consider the requirements
for all mounted components.
1.1.1 Fan-Assisted
Models
If your Crown amplifi er uses
fan-assisted cooling, make
sure that the front vents and/
or fi lters are never blocked,
and that the exhaust fan
(vented out the back or
Amplifi er Application Guide
6 Chapter 1: Crown Amplifi ers In-Depth
sides) is not blocked or covered by cables. Also, if your
Crown amp has foam fi lters, they can be cleaned with mild
dish detergent and water when needed.
The side walls of the rack should be at least 2 inches (5
cm) away from the chassis for amps with side venting as
shown in Figure 1.1.
Don’t use vented spacer panels between amps in a rack.
Because of the airfl ow technology we use in our amps,
it is best to stack multiple amplifi ers on top of each other
with no space between.
The amplifi er draws fresh air into the front of the amp
and exhausts it either out the sides and into the rack, or
out the back depending on the model. We want the hot
air that’s in the rack to vent out the sides or back—not
the front. If any of these amplifi ers are spaced apart with
vented panels, some of the preheated air will recycle to
the front of the rack and back into the amplifi er. The result
is loss of thermal headroom. If you choose to place the amplifi ers with space
between them, then use solid panels between them, not vented panels.
You should provide adequate airfl ow within the rack. Additional air fl ow may
be required when driving low impedance loads at consistently high output
levels or for higher power models. Refer to your Crown amplifi er’s Operation
Manual for detailed information on thermal dissipation.
If your rack has a front door that could
block air fl ow to the amplifi er’s air
intakes, you must provide adequate air
fl ow by installing a grille in the door or
by pressurizing the air behind the door.
Wire grilles are recommended over
perforated panels because they tend
to cause less air restriction. A good
choice for pressurizing the air behind a
rack cabinet door is to mount a “squirrel
cage” blower inside the rack (Option 1
in Figure 1.2). At the bottom of the rack,
mount the blower so it blows outside air
into the space between the door and in
front of the amplifi ers, pressurizing the
“chimney” behind the door. This blower should not blow air into or take air out
of the space behind the amplifi ers. For racks without a door, you can evacuate the rack by mounting the blower at the top of the rack so that air inside the
cabinet is drawn out the back (Option 2 in Figure 1.2).
If the air supply is unusually dusty, you might want to pre-fi lter it using commercial furnace fi lters to prevent rapid loading of the unit’s own air fi lter.
Overheating
Because of the wide range of operating
conditions your amplifer might be subjected to in the fi eld, you should consider each installation independently to
ensure the best thermal performance.
If your amp starts to overheat, consider
the following possible causes:
1. Insuffi cient air movement.
2. Overdriving of the input stage
(severely into clip).
3. Very low-impedance loads.
4. High ambient temperatures.
Figure 1.2
Extra Cooling with a
Rack-Mounted Blower
1.1.2 Convection-Only Models
When racking convection-cooled amplifi ers, it is best to leave one rack-space
between amps because this type of amplifi er needs space to radiate the heat.
Amplifi er Application Guide
Chapter 1: Crown Amplifi ers In-Depth 7
1.2 System Wiring
The information in this section covers making input and output wiring connections, as well as troubleshooting problems relating to system wiring.
1.2.1 Input Wiring
Input Connector Wiring
Refer to the following diagrams for input cable wiring for commonly-used connector types.
Note: These diagrams follow the AES wiring convention of Pin 2 = hot for XLR
connectors.
Balanced, Grounded Source
For use with components equipped with three-wire
grounded AC line cord or other ground connection.
Balanced, Floating Source
For use with components equipped with two-wire
AC line cord or battery power.
Note: If two or more channels with the same
input ground reference are driven from the
same fl oating source, connect only one shield
to the source chassis
Amplifi er Application Guide
8 Chapter 1: Crown Amplifi ers In-Depth
Unbalanced, Grounded Source,
Twin-Lead Shielded Cable
For use with components equipped with three-wire
grounded AC line cord or other ground connection.
Unbalanced, Floating Source,
Twin-Lead Shielded Cable
For use with components equipped with two-wire
AC line cord or battery power.
Unbalanced, Grounded Source, Single-
Conductor Coax or Twisted-Pair Cable
For use with components equipped with three-wire
grounded AC line cord or other ground connection.
Unbalanced, Floating Source, Single-
Conductor Coax or Twisted-Pair Cable
For use with components equipped with two-wire
AC line cord or battery power.
Amplifi er Application Guide
Chapter 1: Crown Amplifi ers In-Depth 9
1.2.2 Solving Input
Input Wiring Tips
1. For all input connectivity, use
shielded wire only. Cables with a foil
wrap shield or a high-density braid
are superior. Cables with a stranded
spiral shield, although very fl exible,
will break down over time and cause
noise problems.
2. Try to avoid using unbalanced
lines with professional equipment. If
you have no choice, keep the cables
as short as possible (see “Balanced
vs. Unbalanced” on the next page).
3. To minimize hum and crosstalk,
avoid running low-level input cables,
high-level output wires and AC power
feeds in the same path. Try to run
differing signal-cable paths at 90°
Figure 1.3
Subsonic Filter Capacitor Values
Figure 1.4
Unbalanced RFI Filters
to one another. If you must use a
common path for all cables, use
a star-quad cable for the low-level
signals.
4. Before changing input connectors or wiring, turn the amplifi er level
controls all the way down (counterclockwise).
5. Before changing output connections, turn the amplifi er level down
and the AC power off to minimize the
chance of short-circuiting the output.
local radio stations, tape recorder bias and digital signal processors (DSP). To prevent high
levels of input RF, install an appropriate low-pass fi lter in series with the input signal.
Some examples of unbalanced wiring for low-pass fi lters are shown in Figure 1.4.
For balanced input wiring use one of the examples in Figure 1.5. Filters A, B and C correspond
to the unbalanced fi lters above. Filter D also incorporates the infrasonic fi lter described previously.
Hum and Buzz
(ungrounded, 2-prong) or grounded (3-prong). Finally, if the source in unbalanced, check the
type of wiring: twin-lead or single coax. Once you have determined the wiring scheme and
cable type, refer to the applicable wiring diagram in Section 1.2.1.
Problems
Infrasonic (Subaudible)
Frequencies
Sometimes large infrasonic (subaudible) frequencies are present in
the input signal. These can damage
loudspeakers by overloading or
overheating them. To attenuate such
frequencies, place a capacitor in
series with the input signal line. The
graph in Figure 1.3 shows some
capacitor values and how they affect
the frequency response. Use only
low-leakage paper, mylar or tantalum
capacitors.
Radio Frequencies (RF)
Another problem to avoid is the
presence of large levels of radio
frequencies or RF in the input signal.
Although high RF levels may not
pose a threat to the amplifi er, they
can burn out tweeters or other loads
that are sensitive to high frequencies. Extremely high RF levels can
also cause your amplifi er to prematurely activate its protection circuitry,
resulting in ineffi cient operation. RF
can be introduced into the signal
chain from many sources such as
If you have noticeable hum or buzz
in your system, you may want to
check your cable connections to
see if the unwanted noise is being
introduced via a ground loop. To
determine the proper wiring, fi rst
check whether the output from
your source is unbalanced or balanced (if you don’t know, refer to
the unit’s back panel or Operation
Manual). Next, determine if the
source’s power cable is fl oating
Amplifi er Application Guide
10 Chapter 1: Crown Amplifi ers In-Depth
Balanced vs. Unbalanced
A balanced audio circuit will have both
positive (+) and negative (–) legs of
the circuit that are isolated from the
ground circuit. These balanced legs
exhibit identical impedance characteristics with respect to ground, and may
also carry the audio signal at the same
level, but with opposite polarities. This
results in a line that offers excellent
rejection of unwanted noise.
On the other hand, an unbalanced
circuit usually holds one leg at ground
potential, while the second leg is “hot.”
Unbalanced line is less expensive, but
is much more susceptible to noise, and
is not normally used in professional
applications. For the cleanest signal,
Figure 1.5
Balanced RFI Filters
with less hum and buzz, a balanced
line is always recommended. It is especially helpful if you have a long cable
run (over 10 feet (3 m)), since noise is
easily introduced into long, unbalanced
lines.
1.3 Output Wiring
1.3.1 Output Connector Wiring
5-Way Binding Post
If the amplifi er is set for Stereo
(Dual), connect the positive (+)
and negative (–) leads of each
loudspeaker to the appropriate Channel 1 and Channel 2
output connectors as shown in
Figure 1.6.
If the amplifi er is set for Bridge-Mono (if equipped), connect a mono load across the red binding posts of each
channel as shown in Figure 1.7. Do NOT use the black
binding posts when the amp is set for Bridge Output.
Notice that the Channel 1 red binding post is positive
(+) and the Channel 2 red binding post is negative (–).
If amp is set for Parallel-Mono (if equipped), connect
a 14-gauge or larger jumper between the Channel 1
and Channel 2 Positive terminals, then connect a mono
load to the Channel 1 binding posts as shown in Figure
1.8. Do NOT use the Channel 2 binding posts when the
amp is set for Parallel Output. Caution: Never short or
parallel the output channels of an amplifi er to itself
or to any other amplifi er.
Figure 1.6
5-Way Binding Post
Wiring for Stereo
Figure 1.7
5-Way Binding Post
Wiring for Bridge-Mono
Figure 1.8
5-Way Binding Post
Wiring for ParallelMono
Amplifi er Application Guide
Chapter 1: Crown Amplifi ers In-Depth 11
Barrier Block
If the amplifi er is set for Stereo (Dual), connect the positive (+) and negative (–) leads
of each loudspeaker to the appropriate Channel 1 and Channel 2 output connectors
Figure 1.9
Barrier Block Wiring for
Stereo
Figure 1.10
Barrier Block Wiring for
Bridge-Mono
Figure 1.11
Barrier Block Wiring for
Parallel-Mono
is set for Bridge Output.
If the amplifi er is set for Parallel-Mono (if
equipped), connect 14-guage or larger
jumper between the Channel 1 and Channel
2 Positive terminals, then connect a mono
load to the Channel 1 positive and negative
terminals as shown in Figure 1.11. Do NOT
use the Channel 2 terminals when the amp
is set for Parallel Output. Caution: Never
short or parallel the output channels of an
amplifi er to itself or to any other amplifi er.
as shown in Figure 1.9.
If the amplifi er is set for
Bridge-Mono (if equipped),
connect a mono load across
the positive terminals of each
channel as shown in Figure
1.10. Do NOT use the negative terminals when the amp
Output Wiring Tips
1. To prevent possible short circuits,
wrap or otherwise insulate exposed
loudspeaker cable or cable connectors.
2. Do not use connectors that might
accidentally tie conductors together
when making or breaking the connection (for example, a standard, 1/4-inch
stereo phone plug).
3. Never use connectors that could
be plugged into AC power sockets.
Accidental AC input will be an electrifying experience for your equipment.
But you will fi nd out real quick if your
speakers are any good at 60 Hz!
4. Avoid using connectors with low current-carrying capacity, such as XLRs.
5. Do not use connectors that have
any tendency to short.
Neutrik® Speakon
To assemble the Neutrik Speakon NL4FC connector, complete
the following steps:
1. Slide the bushing (E) and chuck (D) onto the end of the cable
as shown in Figure 1.12.
Note: Your NL4FC connector kit should contain both a black
and a white chuck. Use the white chuck for cable with a diameter of 0.25 to 0.5 inch (6.35 to 12.7 mm). Use the black chuck
for cable with a diameter of 0.375 to 0.625 inch (9.525 to
15.875 mm).
2. Strip approximately 3/4-inch (20-mm) of casing from the cable
end. Strip approximately 3/8-inch (8-mm) from the end of each
of the conductors down to bare wire (C).
3a. Insert each wire into the top of appropriate slot of the connec-
tor insert (B) as shown in Figure 1.13. Use a (1.5-mm) allen
wrench or fl at blade screwdriver to tighten the side connecting
screws.
®
Amplifi er Application Guide
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