Crown Com Tech 1610, Com Tech 210, Com Tech 410, Com Tech 810, CT-1610 Owners manual

CO M-TE CH®

Models:

Com-Tech 210, 410, 810 & 1610

Some models may be exported under the name

© 2001 by Crown Audio, Inc., P.O. Box 1000, Elkhart, IN 46515-1000 U.S.A. Telephone: [phone]. Fax: [phone]. Trademark
Notice:
respective owners.

Obtaining Other Language Versions:

To obtain information in another language about the use of this product, please contact your local Crown Distributor. If you need assistance
locating your local distributor, please contact Crown at 219-294-8200.

Amcron

®

,

BCA

®

and

Crown

®

are registered trademarks of Crown International, Inc. Other trademarks are the property of their

Amcron

Note: The information provided in this manual was deemed accurate as of the publication date. However, updates to this information

may have occurred. To obtain the latest version of this manual, please visit the Crown website at www.crownaudio.com.

Applies to
CT-410 and CT-810
Crown and Amcron
models

®

.

101969-6

3/01

Com-Tech Power Amplifiers

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Page 2

Reference Manual

Com-Tech Power Amplifiers

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 grounding­type 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 fit 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 speci­fied 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 tip­over.

13) Unplug this apparatus during lightning 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 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.

15) To reduce the risk of fire or electric shock, do not ex­pose this apparatus to rain or moisture.

Reference Manual

Page 3

3

YEAR

THREE YEAR

FULL WARRANTY

3

YEAR

WORLDWIDE

The Crown Audio Division of Crown International, Inc., 1718 West
Mishawaka Road, Elkhart, Indiana 46517-4095 U.S.A. warrants to you, the
ORIGINAL PURCHASER and ANY SUBSEQUENT OWNER of each
NEW Crown
purchase by the original purchaser (the “warranty period”) that the new
Crown product is free of defects in materials and workmanship, and we
further warrant the new Crown product regardless of the reason for failure,
except as excluded in this Crown Warranty.

1

Note: If your unit bears the name “Amcron,” please substitute it for the

name “Crown” in this warranty.

ITEMS EXCLUDED FROM THIS CROWN WARRANTY

This Crown Warranty is in effect only for failure of a new Crown product
which occurred within the Warranty Period. It does not cover any product
which has been damaged because of any intentional misuse, accident,
negligence, or loss which is covered under any of your insurance contracts.
This Crown Warranty also does not extend to the new Crown product if the
serial number has been defaced, altered, or removed.

We will remedy any defect, regardless of the reason for failure (except as
excluded), by repair, replacement, or refund. We may not elect refund
unless you agree, or unless we are unable to provide replacement, and
repair is not practical or cannot be timely made. If a refund is elected, then
you must make the defective or malfunctioning product available to us free
and clear of all liens or other encumbrances. The refund will be equal to the
actual purchase price, not including interest, insurance, closing costs, and
other finance charges less a reasonable depreciation on the product from
the date of original purchase. Warranty work can only be performed at our
authorized service centers. We will remedy the defect and ship the product
from the service center within a reasonable time after receipt of the
defective product at our authorized service center.

You must notify us of your need for warranty service not later than ninety
(90) days after expiration of the warranty period. All components must be
shipped in a factory pack. Corrective action will be taken within a
reasonable time of the date of receipt of the defective product by our
authorized service center. If the repairs made by our authorized service
center are not satisfactory, notify our authorized service center
immediately.

DISCLAIMER OF CONSEQUENTIAL AND INCIDENTAL DAMAGES

YOU ARE NOT ENTITLED TO RECOVER FROM US ANY INCIDENTAL
DAMAGES RESULTING FROM ANY DEFECT IN THE NEW CROWN
PRODUCT. THIS INCLUDES ANY DAMAGE TO ANOTHER PRODUCT
OR PRODUCTS RESULTING FROM SUCH A DEFECT.

No person has the authority to enlarge, amend, or modify this Crown
Warranty. This Crown Warranty is not extended by the length of time which
you are deprived of the use of the new Crown product. Repairs and
replacement parts provided under the terms of this Crown Warranty shall
carry only the unexpired portion of this Crown Warranty.

We reserve the right to change the design of any product from time to time
without notice and with no obligation to make corresponding changes in
products previously manufactured.

No action to enforce this Crown Warranty shall be commenced later than
ninety (90) days after expiration of the warranty period.

THIS STATEMENT OF WARRANTY SUPERSEDES ANY OTHERS

CONTAINED IN THIS MANUAL FOR CROWN PRODUCTS.

Telephone: [phone]. Facsimile: 219-294-8301

SUMMARY OF WARRANTY

1

product, for a period of three (3) years from the date of

WHAT THE WARRANTOR WILL DO

HOW TO OBTAIN WARRANTY SERVICE

WARRANTY ALTERATIONS

DESIGN CHANGES

LEGAL REMEDIES OF PURCHASER

9/90

NORTH AMERICA

The Crown Audio Division of Crown International, Inc., 1718 West Mishawaka
Road, Elkhart, Indiana 46517-4095 U.S.A. warrants to you, the ORIGINAL
PURCHASER and ANY SUBSEQUENT OWNER of each NEW Crown product,
for a period of three (3) years from the date of purchase by the original purchaser
(the “warranty period”) that the new Crown product is free of defects in materials
and workmanship. We further warrant the new Crown product regardless of the
reason for failure, except as excluded in this Warranty.

ITEMS EXCLUDED FROM THIS CROWN WARRANTY

This Crown Warranty is in effect only for failure of a new Crown product which
occurred within the Warranty Period. It does not cover any product which has
been damaged because of any intentional misuse, accident, negligence, or loss
which is covered under any of your insurance contracts. This Crown Warranty
also does not extend to the new Crown product if the serial number has been
defaced, altered, or removed.

We will remedy any defect, regardless of the reason for failure (except as
excluded), by repair, replacement, or refund. We may not elect refund unless you
agree, or unless we are unable to provide replacement, and repair is not practical
or cannot be timely made. If a refund is elected, then you must make the defective
or malfunctioning product available to us free and clear of all liens or other
encumbrances. The refund will be equal to the actual purchase price, not
including interest, insurance, closing costs, and other finance charges less a
reasonable depreciation on the product from the date of original purchase.
Warranty work can only be performed at our authorized service centers or at the
factory. We will remedy the defect and ship the product from the service center
or our factory within a reasonable time after receipt of the defective product at our
authorized service center or our factory. All expenses in remedying the defect,
including surface shipping costs in the United States, will be borne by us. (You
must bear the expense of shipping the product between any foreign country and
the port of entry in the United States and all taxes, duties, and other customs fees
for such foreign shipments.)

You must notify us of your need for warranty service not later than ninety (90)
days after expiration of the warranty period. All components must be shipped in
a factory pack, which, if needed, may be obtained from us free of charge.
Corrective action will be taken within a reasonable time of the date of receipt of
the defective product by us or our authorized service center. If the repairs made
by us or our authorized service center are not satisfactory, notify us or our
authorized service center immediately.

DISCLAIMER OF CONSEQUENTIAL AND INCIDENTAL DAMAGES

YOU ARE NOT ENTITLED TO RECOVER FROM US ANY INCIDENTAL
DAMAGES RESULTING FROM ANY DEFECT IN THE NEW CROWN
PRODUCT. THIS INCLUDES ANY DAMAGE TO ANOTHER PRODUCT OR
PRODUCTS RESULTING FROM SUCH A DEFECT. SOME STATES DO

NOT ALLOW THE EXCLUSION OR LIMITATIONS OF INCIDENTAL OR
CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATION OR
EXCLUSION MAY NOT APPLY TO YOU.

No person has the authority to enlarge, amend, or modify this Crown Warranty.
This Crown Warranty is not extended by the length of time which you are
deprived of the use of the new Crown product. Repairs and replacement parts
provided under the terms of this Crown Warranty shall carry only the unexpired
portion of this Crown Warranty.

We reserve the right to change the design of any product from time to time without
notice and with no obligation to make corresponding changes in products
previously manufactured.

THIS CROWN WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, YOU
MAY ALSO HAVE OTHER RIGHTS WHICH VARY FROM STATE TO STATE.
No action to enforce this Crown Warranty shall be commenced later than ninety
(90) days after expiration of the warranty period.

THIS STATEMENT OF WARRANTY SUPERSEDES ANY OTHERS

CONTAINED IN THIS MANUAL FOR CROWN PRODUCTS.

Telephone: [phone]. Facsimile: 219-294-8301

SUMMARY OF WARRANTY

WHAT THE WARRANTOR WILL DO

HOW TO OBTAIN WARRANTY SERVICE

WARRANTY ALTERATIONS

DESIGN CHANGES

LEGAL REMEDIES OF PURCHASER

9/90

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 your unit bears the name “Amcron,” please substitute it for the name “Crown” in this manual. If you need
special assistance beyond the scope of this manual, please contact our Technical Support Group.

Crown Technical Support Group

Plant 2 SW, 1718 W. Mishawaka Rd., Elkhart, Indiana 46517 U.S.A.

Phone: [phone] (North America, Puerto Rico and Virgin Islands) or 219-294-8200

Fax: [phone] Internet: http://www.crownaudio.com

C A U T I O N

RISK OF ELECTRIC SHOCK

DO NOT OPEN

TO PREVENT ELECTRIC SHOCK DO

NOT REMOVE TOP OR BOTTOM

COVERS. NO USER SERVICEABLE

PARTS INSIDE. REFER SERVICING TO

QUALIFIED SERVICE PERSONNEL.

DISCONNECT POWER CORD BE-

FORE REMOVING REAR INPUT

MODULE TO ACCESS GAIN SWITCH.

WARNING

TO REDUCE THE RISK OF ELECTRIC

SHOCK, DO NOT EXPOSE THIS

EQUIPMENT TO RAIN OR MOISTURE!

A V I S

RISQUE DE CHOC ÉLECTRIQUE

N’OUVREZ PAS

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.

DÉBRANCHER LA BORNE AVANT

D’OUVRIR LA MODULE EN ARRIÈRE.

Magnetic Field

CAUTION! Do not locate sensitive high-gain
equipment such as preamplifiers or tape decks
directly above or below the unit. Because this

amplifier has a high power density, it has a strong
magnetic field which can induce hum into unshielded
devices that are located nearby. The field is stron­gest just above and below the unit.

If an equipment rack is used, we recommend locat­ing the amplifier(s) in the bottom of the rack and the
preamplifier or other sensitive equipment at the top.

WATCH FOR THESE SYMBOLS:

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 maintenance instructions.

Printed on

recycled paper.

CONTENTS

1 Welcome ............................................................................ 9

1.1 Unpacking ................................................................... 9

1.2 Features....................................................................... 9

2 Facilities .......................................................................... 10

3 Installation ....................................................................... 12

3.1 Mounting ................................................................... 12

3.2 Cooling ...................................................................... 12

3.2.1 Cooling for Units without Internal Fans ............. 13

3.2.2 Additional Cooling for Units with Internal Fans . 13

3.3 Wiring ........................................................................ 14

3.3.1 Mode of Operation .......................................... 14

3.3.2 Audio Input Connection ................................... 19

3.3.3 RSVP Input Connections .................................. 21

3.3.4 Output Connection .......................................... 21

3.3.5 Additional Load Protection ............................... 23

3.4 AC Power Requirements ............................................ 24

Com-Tech Power Amplifiers

4 Operation ......................................................................... 25

4.1 Precautions ................................................................ 25

4.2 Indicators................................................................... 25

4.3 Protection Systems .................................................... 26

4.3.1 ODEP .............................................................. 26

4.3.2 Standby Mode ................................................. 27

4.3.3 Transformer Thermal Protection ....................... 27

4.3.4 Circuit Breaker................................................. 27

4.4 Controls ..................................................................... 28

4.5 Energy Savings Circuit Application ............................ 29

4.6 Filter Cleaning ............................................................ 29

5 Technical Information...................................................... 29

5.1 Overview ................................................................... 29

5.2 Circuit Theory ............................................................ 30

5.2.1 Dual Operation ................................................ 30

5.2.2 Bridge-Mono Operation ................................... 31

5.2.3 Parallel-Mono Operation .................................. 31

6 Specifications .................................................................. 32

7 AC Power Draw and Thermal Dissipation ....................... 45

8 Accessories ..................................................................... 47

8.1 PIP and PIP2 Modules................................................ 47

8.2 RSVP Module ............................................................ 49

8.3 Cooling Fan Option (120 VAC, 60 Hz only) ................. 49

8.4 Constant Voltage Computer ....................................... 49

Page 6

9 Service ............................................................................. 50

9.1 Worldwide Service ..................................................... 50

9.2 North American Service ............................................. 50

9.2.1 Service at a North American Service Center .... 50

9.2.2 Factory Service ............................................... 50

Reference Manual

Com-Tech Power Amplifiers

1.1

2.1 Front Facilities ......................................................................... 10

2.2 Rear Facilities ......................................................................... 11

3.1 Mounting Dimensions .............................................................. 12

3.2 Top View of a Rack-Mounted Unit ............................................ 13

3.3 Extra Cooling with a Rack-Mounted Blower ............................. 14

3.4 Wiring for Dual 8/4 Ohm Mode ................................................ 15

3.5 Wiring for Dual 70 Volt Mode ................................................... 16

3.6 Wiring for Bridge-Mono 70 Volt Mode (140 Volt Output) ........... 17

3.7 Wiring for Parallel-Mono 70 Volt, Bridge-Mono 8/4 Ohm

3.8 Balanced Input Wiring .............................................................19

3.9 Unbalanced Input Wiring......................................................... 19

3.10 Infrasonic Filter Capacitor Values ............................................ 20

3.11 Unbalanced RFI Filters ............................................................ 20

3.12 Balanced RFI Filters ................................................................ 20

3.13 Connecting the RSVP Module ................................................. 21

3.14 Wire Size Nomograph ............................................................. 22

3.15 Inductive Load (Transformer) Network ..................................... 23

3.16 Loudspeaker Fuse Nomograph ............................................... 24

4.1 Indicators ................................................................................ 25

4.2

4.3 Input Sensitivity Switch ............................................................ 28

5.1 Circuit Block Diagram ............................................................. 30

6.1

6.2

6.3

6.4

6.5

6.6

6.7

6.8

6.9 Typical Frequency Response .................................................. 43

6.10 Typical Damping Factor .......................................................... 43

6.11 Typical Output Impedance ...................................................... 43

6.12 Typical Phase Response ......................................................... 44

6.13 Typical Crosstalk ..................................................................... 44

7.1

7.2

7.3

7.4

8.1

8.2 Installing a

ILLUSTRATIONS

Com-Tech

and Parallel-Mono 8/4 Ohm Modes ......................................... 18

ODEP, IOC

Com-Tech 210
Com-Tech 410
Com-Tech 810
Com-Tech 1610
Com-Tech 210
Com-Tech 410
Com-Tech 810
Com-Tech 1610

Com-Tech 210

Thermal Dissipation at Various Duty Cycles ............................. 45

Com-Tech 410

Thermal Dissipation at Various Duty Cycles ............................. 46

Com-Tech 810

Thermal Dissipation at Various Duty Cycles ............................. 46

Com-Tech 1610

Thermal Dissipation at Various Duty Cycles ............................. 46

PIP2

Amplifiers (120 VAC, 60 Hz Units) ............................. 8

and Signal Presence Indicator States .................... 26

Minimum Power Matrix ..................................... 35

Minimum Power Matrix ..................................... 36

Minimum Power Matrix ..................................... 37

Minimum Power Matrix ................................... 38

Maximum Power Matrix .................................... 39

Maximum Power Matrix .................................... 40

Maximum Power Matrix .................................... 41

Maximum Power Matrix .................................. 42

Power Draw, Current Draw and

Power Draw, Current Draw and

Power Draw, Current Draw and

Power Draw, Current Draw and

Adaptor Connection ........................................................ 47

PIP

Module ............................................................ 47

Reference Manual

Page 7

Com-Tech Power Amplifiers

Page 8

Fig. 1.1 Com-Tech Amplifiers (120 VAC, 60 Hz Units)

Reference Manual

Com-Tech Power Amplifiers

1 Welcome

Congratulations on your purchase of a Com-Tech® com­mercial power amplifier. The Com-Tech series is a com­plete family of amplifiers with a wide range of power
output capabilities. Com-Tech amplifiers can directly
drive “constant voltage” lines, so you can avoid the ex­pense, distortion and insertion loss associated with
step-up transformers for distributed loudspeaker sys­tems. Com-Tech amplifiers also utilize Crown’s patented
ODEP® protection circuitry which

working

under severe conditions that would shut down
a lesser amplifier. All Com-Tech amplifiers feature
Crown’s exclusive PIP™ (Programmable Input Proces­sor) expansion system. The PIP expansion system
makes it easy to tailor your amplifier to a specific appli­cation or to add future technology as it develops (see
Section 8 for a list of available PIPs).

This manual will help you successfully install and use
your new Com-Tech amplifier. Please read all instruc­tions, warnings and cautions. Be sure to read Section

3.3.1 if you plan to use the amplifier in one of its two
mono modes, or if you plan to drive “constant voltage”
lines. Also, for your protection, please send in your war­ranty registration card today, and save your bill of sale
as it is your official proof of purchase.

1.1 Unpacking

Please unpack and inspect your new amplifier for any
damage that may have occurred during transit. If dam­age is found, notify the transportation company imme­diately. Only you, the consignee, may initiate a claim for
shipping damage. Crown will be happy to cooperate
fully, as needed. Save the shipping carton as evidence
of damage for the shipper’s inspection.

Even if the unit arrived in perfect condition, (as most
do), save all packing materials, so you will have them if
you ever need to transport the unit. NEVER SHIP THE

UNIT WITHOUT THE FACTORY PACK.

1.2 Features

Com-Tech amplifiers use cutting-edge technology and
miniaturized design to provide the highest power and
value for its size, weight and price. They offer numerous
advantages over conventional designs and provide
benefits you can’t get in amplifiers from any other manu­facturer. For example, Crown’s patented ODEP protec­tion circuitry
combine to provide performance and reliability that sur­pass the other, more traditional, designs. Here are some
more of your amplifier’s impressive features:

and grounded bridge

keeps the amplifier

™

output stages

❏ “Soft-Start” inrush current limiting protects the house

circuit breaker when several amps are turned on simulta­neously.

❏ Remote feature allows CT-10 Series amplifiers to be

turned on and off from a remote location. Placing the
Enable switch on the amplifier’s front panel to the Remote
position allows the optional
Voltage Provider) module to control the amplifier.

❏ Energy Saving circuit allows a CT-10 Series

cut back its energy consumption based on the signal
level offered to the inputs.

❏ Crown’s patented ODEP (Output Device Emulation Pro-

tection) circuitry detects and compensates for overheat­ing and overload to keep the amplifier working when
others would fail.

❏ Crown’s grounded bridge design delivers incredible volt-

age swings without using stressful output transistor con­figurations like conventional amplifiers. The results are
lower distortion and superior reliability.

❏

❏ Enhanced PIP2

❏ Drives constant voltage lines without “lossy,” distortion-

❏ Two mono modes (Bridge-Mono and Parallel-Mono) for

❏ Very low harmonic and intermodulation distortion give

❏ Superior damping factor delivers maximum loudspeaker

❏ Superb crosstalk characteristics and a separate voltage

❏ Full protection from shorted, open and mismatched

❏ Efficient heat sinks and a fully proportial speed fan

❏ Barrier blocks are provided for both input and output

❏ Internal three-position input sensitivity switch provides

❏ Mounts in a standard 19-inch (48.3-cm) equipment rack.
❏ Three year “No-Fault” full warranty completely protects

®

IOC

(Input/Output Comparator) circuitry immediately

alerts you if distortion is present. You have real-time

of distortion-free performance

(Programmable Input Processor)
connector accepts new accessory modules that further
tailor the amplifier to suit specific applications,
including wideband load current monitoring.

producing step-up transformers.

driving a wide range of load impedances.

the best

motion control for a clean, accurate low end.

supply for each channel make it possible to treat each
channel like a separate amplifier.

loads, general overheating. DC, high-frequency over­loads, and full internal fault protection are provided by
our latest protection scheme: “Quad-Mute.”

sipate heat quickly and evenly for extra amplifier protec­tion and extended component life. (The fan is an option
for 120 VAC, 60 Hz

connections. New input barrier blocks incorporate a test

point

settings of 0.775 volts for full standard 1-kHz 8/4-ohm
power, 0.775 volts for full standard 1-kHz 70-volt power,
and 26-dB voltage gain.

your investment and guarantees its specifications.

dynamic transfer function

Com-Tech 210

for a DVM.

R.S.V.P.

(Remote Switching

.

in the industry.

s.)

amplifier to

proof

dis-

Reference Manual

Page 9

2 Facilities

Com-Tech Power Amplifiers

Fig. 2.1 Front Facilities

A. Filter Grille

A metal grille supports and protects the dust filter (B).
To clean the dust filter, detach the grille by removing the
screws that fasten it in place.

B. Dust Filter

The dust filter removes large particles from air drawn by
the cooling fan. (The fan is an option for 120 VAC, 60 Hz
Com-Tech 210s.) Clean the filter regularly to prevent
clogging (see Section 4.5).

C. ODEP Indicators

Each channel has an amber front panel indicator that
shows thermal-dynamic energy reserve. Normally, each
ODEP indicator is lit to show available reserve energy.
The indicator will dim proportionally as the energy re­serve for its channel decreases. In the rare event that a
channel has no reserve, its indicator will turn off and the
ODEP circuitry will limit the channel’s output drive (see
Section 4.2).

D. IOC Indicators

The yellow IOC (Input/Output Comparator) indicators
serve as sensitive distortion indicators to provide

of distortion-free performance

tions, the indicators remain off. They light up if the out­put waveform differs from the input by 0.05% or more.
In addition, when the amplifier is running in parallel/
mono mode, CH2 IOC stays on under normal condi­tions (see Section 4.2).

. Under normal condi-

proof

E. Signal Presence Indicators (SPI)

The signal presence indicators flash synchronously with
the amplifier’s audio output, when the output voltage is
greater than 34 mV. (see Section 4.2).

F. Enable Indicator

This indicator lights when the amplifier has been en­abled, or turned on, and AC power is available. The
enable indicator will dim when the energy saving circuit
is activated (see Section 4.2).

G. Enable Switch

This rocker switch is used to turn the amplifier on, off,
and enable the remote feature. When turned on by ei­ther the rocker switch or the remote R.S.V.P. module, the
output is muted for about four seconds to protect your
system from any turn-on transients. Delay times vary
slightly from one unit to the next, so there is always a
certain amount of “randomness”. Turn-on inrush is lim­ited by Soft-Start circuitry, so Com-Tech amplifiers never
need a power sequencer. (To change the turn-on delay
time, contact Crown’s Technical Support Group.)

H. Power Cord

All 120 VAC, 60 Hz North American units have a
NEMA 5-15P plug with an integral voltage presence
lamp. These units include a 16-gauge power cord with
each Com-Tech 210 and 410, and a 14-gauge cord with
each Com-Tech 810 and 1610. Other units have an ap­propriate power cord and plug. All Com-Tech “10” Se­ries amps utilize a convenient 3-foot-long power cord.

To meet full regulatory compliance, these cords
must be plugged into a local, cabinet mounted, com­mercial grade electrical outlet box. “Extension”
cords are not recommended or adequate.

Section 7 for more information on power usage.

Refer to

I. Reset Switch

This reset switch is used to reset the circuit breaker that
protects the power supplies from overload (see Sec­tions 4.3.4 and 4.4).

Page 10

Reference Manual

Com-Tech Power Amplifiers

Fig. 2.2 Rear Facilities

(Domestic Model Shown)

J. Dual/Mono Switch

For 8- and 4-ohm operation, remove the cover plate, if
so equipped, then slide this switch to the center for Dual
(two-channel) mode, to the left for Parallel-Mono mode
or to the right for Bridge-Mono mode.

WARNING: Do not change this switch unless the
amplifier is turned off. Do NOT use the Bridge-Mono
or Parallel-Mono modes unless both output mode
switches (O) are set the same.

the installation requirements for each mode (see Sec­tion 3.3.1).

Also, be sure to follow

K. Remote Input

For remote operation, an RJ11 jack is used to connect
the amplifier to the optional R.S.V.P. (Remote Switching
Voltage Provider) module. Do not connect to phone line.

L. PIP Module

The standard
provides barrier block input connectors equipped with
test points for your DVM. Other PIP modules can be
used in place of the PIP2-BB to provide additional fea­tures that customize the amplifier for different applica­tions. First generation PIPs require the “PIP2 Adapter”
for accessory connectivity (see Section 8 for available
PIP modules).

PIP2-BB

is included with your amplifier. It

also be set to 0.775 volts for 1 kHz output in 70-volt
mode, or an overall voltage gain of 26 dB (see Section

4.4).

N. Input Attenuation Controls

Each channel’s output level can be adjusted accurately
using these 21-position detented controls on the back
panel. A Lexan cover is also included that can be used
to discourage tampering (see Section 4.4).

O. Balanced Barrier Block Inputs

The PIP2-BB is included in the standard configuration.
It provides a balanced barrier block with three termi­nals for each input channel, as well as test points for a
DVM. (XLR connectors are also available—see Section

8.1.)

P. Output Mode Switches

The output mode switches are used to configure each
channel independently for either 8/4-ohm loads or 70­volt (“constant voltage”) lines.

WARNING: Do not change these switches unless the
amplifier is off. Do NOT use the Bridge-Mono or Par­allel-Mono modes unless these switches are set the
same.

Also, be sure to follow the special installation re-

quirements for each mode (see Section 3.3.1).

M. Input Sensitivity Switch (not shown)

The three-position Input Sensitivity Switch located in­side the amplifier is accessed by removing the PIP
module. It is set at the factory to 0.775 volts for maxi­mum average power (1 kHz power into 8 ohms). It can

Reference Manual

Q. Output Barrier Block

A barrier block with four terminals is provided for output
connection. Output wiring will vary depending on the
selected dual/mono mode and whether 70-volt output
will be used (see Section 3.3.1).

Page 11

Com-Tech Power Amplifiers

3 Installation

This section covers basic Com-Tech installation proce­dures. All Com-Tech amplifiers are intended for rack

mount installations using a commercial 19-inch
(48.3-cm) EIA rack standard metal cabinet wired with
a commercial grade electrical outlet box and recep­tacles. All Com-Tech Amplifiers utilize a convenient
3-foot long (0.9-m) power cord for such installations.

3.1 Mounting

Com-Tech amplifiers are designed for standard 19-inch
(48.3-cm) rack mounting or stacking without a cabinet.
In a rack, it is best to mount units directly on top of each
other. This provides the most efficient air flow and sup­port. If the rack will be transported, we recommend that
you fasten the amplifier’s back panel securely to the
rack to help support the unit’s weight.

All Com-Tech amplifiers are 19 inches (48.3 cm) wide,
16 inches (40.6 cm) deep, and 0.25 inches (0.6 cm) in
front of the mounting surface. As you can see in Fig­ure 3.1, Com-Tech amplifiers vary in their vertical di­mensions. Figure 3.1 labels the different heights as A, B
and C. These letters correspond to the list that follows
showing

Com-Tech

models and their vertical dimen-

sions.

Height A: 3.5 inches (8.9 cm)

Models: Com-Tech 210 (All)

Com-Tech 410 (North American)

Height B: 5.25 inches (13.3 cm)

Models: Com-Tech 410 (100/120 VAC, 50/60 Hz)

Com-Tech 410 (220/240 VAC, 50/60 Hz)
Com-Tech 810 (All)

Height C: 7 inches (17.8 cm)

Model: Com-Tech 1610 (All)

3.2 Cooling

It is important to understand cooling considerations
when installing a Com-Tech amplifier. First, never block
the amplifier’s front or side air vents. This can cause
poor air flow and may result in overheating. If the ampli­fier is rack-mounted, its sides should be at least
2 inches (5 cm) away from the cabinet (see Figure 3.2).
Also, open spaces in the front of the rack should be
covered with blank panels to prevent improper air flow.
Otherwise, heated air from the side exhaust vents can
be drawn into the front air intake which may greatly re­duce the cooling system’s effectiveness.

Page 12

Fig. 3.1 Mounting Dimensions

Reference Manual

Com-Tech Power Amplifiers

17 in

43.2 cm

IMPORTANT: Be sure the back of

the amplifier is supported.

16 in

40.6 cm

AIR

FLOW

2 in

(5 cm)

MIN.

AMPLIFIER

(TOP VIEW)

AIR FLOW

AIR

FLOW

RACK

CABINET

Fig. 3.2 Top View of a Rack-Mounted Unit

The air flow requirement for a Com-Tech amplifier de­pends on many things, but the most important factor is
average output power. Air flow requirements increase
as output power increases, so anything that affects out­put power also affects the required air flow.

Average output power is mainly affected by three
things: (1) duty cycle of the input signal, (2) load im­pedance, and (3) rated output power. First, as the duty
cycle of the input signal increases, the average output
power level increases. For example, the amplifier will
need more air flow with a rock ‘n’ roll input signal than
with infrequent paging. Second, as the load impedance
of a connected loudspeaker gets smaller, more current
will flow through the load which effectively increases
output power. This means you can expect the amplifier
to require more air flow with a 4-ohm load than with an
8-ohm load. Finally, an amplifier that is rated for higher
power output is usually used at higher average output
levels. So a Com-Tech 1610 delivering full output will
require more air flow than a Com-Tech 210. These rela­tionships and the resulting thermal dissipation levels are
defined mathematically in Section 7.

3.2.1 Cooling for Units without Internal Fans

All units have a continuously variable on-demand cool­ing fan except for the North American Com-Tech 210.
Forced-air cooling may not be needed for applications
with a low duty cycle such as paging or background
music. This is why the North American Com-Tech 210 is
usually provided without a fan.

If you will be using a North American Com-Tech 210 in a
high-temperature environment, or at full power for sus­tained periods, you can anticipate that additional cool­ing will be needed. It may also be helpful to use the

information in Section 7 to estimate the amplifier’s ther­mal dissipation for your application. In general, a North
American Com-Tech 210 that dissipates more than 410
btu (110 kcal) per hour per unit will need additional cool­ing. If you are not sure, observe the ODEP indicators
while the amplifier is operating under worst-case condi­tions. If the indicators dim, additional cooling is recom­mended.

There are at least three ways to provide extra cooling
for an amplifier that does not have an internal fan. The
most effective method is to install an internal fan which
is available from Crown as an accessory (refer to sub­section 8.3). A cooling fan (part GCT200FAN) kit is
available for North American Com-Tech 210s (all other
units include a fan). Crown recommends the kit if you
will be operating the amplifier at high levels or in high
temperatures for long periods. Refer to paragraph 8.3
for more information on the cooling fan kit

A rack-mounted blower or an air conditioner can also
be used to provide extra cooling. In some situations,
you may find it practical to use these methods without
installing a fan in each amplifier. However, we generally
recommend that you use the internal fans because they
provide the most efficient cooling, and are active only
when needed. Amplifiers that already have internal fans
can also take advantage of a rack-mounted blower or
air conditioner, so these approaches will be discussed
in the section that follows.

3.2.2 Additional Cooling for Units with Internal Fans

If multiple amplifiers will be operated under demanding
conditions (such as driving loads less than 4 ohms), or
if air flow through the rack will be restricted, you should
verify that the total air flow through the rack will be suffi­cient. As described in Section 3.2.1, sufficient air flow
can be tested in the real world by observing the ODEP
indicators while operating under worst-case conditions.
If the indicators dim, cooling can be improved by re­ducing air restrictions, installing a rack-mounted blower,
or using an air conditioner.

Many things can cause air flow restrictions, including
improper mounting, bunched up power cords, closed
rack doors, and clogged dust filters. A Com-Tech am­plifier should be mounted in a way that allows sufficient
air flow into the front intakes, out the side exhaust vents,
and out the back of the rack. If your rack has a front
door, it is usually best to leave it open and avoid block­ing the air intakes. If this is impossible, supplement the
air flow by mounting a grille in the door or with a rack­mounted blower. If you install a grille in the door, we
recommend wire grilles instead of perforated panels,

Reference Manual

Page 13

Com-Tech Power Amplifiers

70

VOLT

8/4

OHM

AIR

FLOW

AIR

FLOW

BLOWER

(OPTION 2)

EQUIPMENT

RACK

(SIDE VIEW)

BLOWER

(OPTION 1)

FRONT

OF

RACK

DOOR

Fig. 3.3 Extra Cooling with a Rack-Mounted Blower

because wire tends to cause less air restriction (perfo­rated panels cause a minimum air restriction of 40%).

A better choice for increasing the air flow behind a rack
cabinet door is to use a “squirrel cage” blower. Mount
the blower at the bottom of the rack so it blows outside
air into the space between the door and the front of the
amplifiers, pressurizing the “chimney” behind the door
(Figure 3.3, Option 1). The blower should not blow air
into or take air out of the space behind the amplifiers.
For racks without a front door, you can evacuate the
rack by mounting the blower at the top of the rack so
that air blows out the back (Figure 3.3, Option 2).

You can estimate the required air flow for a rack by add­ing together the maximum required air flow ratings of
the individual units. The internal fan in a Com-Tech 210
(if installed), 410 and 810 can move up to 35 cubic feet
(1 cubic meter) of air per minute, while the internal fan
in a Com-Tech 1610 can move up to 65 cubic feet (1.8
cubic meters) per minute. If you mounted one of each
Com-Tech model in a rack, worst-case conditions would
require 170 cubic feet (4.7 cubic meters) of air flow
through the rack every minute (3 x 35 cubic feet + 65
cubic feet = 170 cubic feet).

Air flow restrictions may also result if the air filter be­comes clogged. If the air supply is unusually dusty, you
can help prevent rapid loading of the unit’s air filter by
pre-filtering the air using commercial furnace filters.
And, when needed, the unit's filter can be cleaned with
mild dish detergent and water (see Section 4.6).

The final method for increased cooling is to use air con­ditioning. Air conditioning is rarely a necessity because
internal fans and rack-mounted blowers almost always

provide enough air flow for even the most extreme con­ditions. Still, air conditioning can help by reducing the
temperature of the air circulated through the rack. If you
intend to install air conditioning for your amplifiers, you
may want to use Section 7 to determine the hourly ther­mal dissipation of your system.

3.3 Wiring

Figures 3.4 through 3.7 show common ways to install a
Com-Tech amplifier in a sound system. Input and out­put terminals are located on the back panel. Please use
care when making connections, selecting signal
sources and controlling the output level. The load you
save may be your own! Crown assumes no liability for
damaged loads resulting from careless amplifier use or
deliberate overpowering.

CAUTION: Always disconnect the AC power and
turn the level controls off when making or breaking
connections. This is very important when loudspeak-

ers are connected because it reduces the chance of
loud blasts that can cause loudspeaker damage.

3.3.1 Mode of Operation

Proper wiring depends on how you configure your am­plifier. First, each output channel can be independently
configured to drive step-down transformers in a distrib­uted “constant voltage” loudspeaker system (70-volt
mode) or loudspeakers that do not have step-down
transformers (8/4-ohm mode). Second, the amplifier
can be configured for Dual, Bridge-Mono or Parallel­Mono modes. Various combinations of these modes are
possible, so be sure to note any special wiring require­ments for the mode you will be using.

7 0 V O L T

The 70-volt output mode is used to drive constant volt­age lines without expensive step-up transformers.
Avoiding the use of step-up transformers not only saves
money, but it also eliminates the distortion and insertion
loss caused by this type of transformer.

Setting up 70-volt mode is easy. Turn off the amplifier,
then slide the recessed output mode switches to the 70
VOLT (right) position.

If required by your system design, Com-Tech amplifiers
can be configured for either bridge-mono or parallel­mono modes of operation. To switch your amplifier ac­cordingly, start by removing power from the unit. Next,

Page 14

Reference Manual

Com-Tech Power Amplifiers

remove the “Dual-Mono” mode switch cover and set
the switch to the desired setting. Then replace the

switch cover plate before restoring power.

WARNING: If you have configured the amplifier to
produce 100 volts output or greater, your output wir­ing must conform to the National Electrical Code
Class 1 wiring requirements.

If Bridge-Mono mode is used with 70-volt output, the
amplifier will actually deliver 140 volts (more informa­tion on this is provided later in this section). To effec­tively use this mode, you may need to cross-reference
power ratings for the step-down transformer taps using
Crown’s constant voltage computer (see Section 8.3).

WARNING: The output mode switches must be set
the same (8/4-ohm or 70-volt mode) when operating
in Bridge-Mono or Parallel-Mono mode.

When connecting a 70-volt step-down transformer, do
not exceed its power rating. Too much power can satu­rate a transformer and cause it to appear as a short
circuit to the amplifier. If this happens, no damage
should occur, but the amplifier may run less efficiently,
and the sound quality may be affected.

8/4

OHM

70

VOLT

8/4-ohm mode is commonly used to drive loudspeak­ers with impedances from 2 to 16 ohms. When using
this output mode, appropriate load impedances will de­pend on the dual/mono mode that you select. The avail­able dual/mono modes (Dual, Bridge-Mono and
Parallel-Mono) will be described in sections that follow.

Configuring your amplifier for 8/4-ohm mode is straight­forward. Turn off the amplifier and slide the output mode
switches to the 8/4 OHM (left) position.

When the amplifier is set up for two-channel (Dual
mode) operation, it is possible to configure one output
channel for 8/4-ohm operation and the other for 70-volt
operation. If you plan to use different output modes like
this, the input sensitivity should be set to 0.775-volts for
70-volt output. This will assure you of having enough
amplifier gain to reach 70-volt output levels with a .775­volt input signal. The 8/4-ohm channel will need to have
it’s level control turned down so that a .775-volt input
signal will not overdrive that channel (see Section 4.4).
ALWAYS configure both channels the same when using
Bridge-Mono or Parallel-Mono modes.

Because of the way Com-Tech amplifiers are designed,
they can be used to directly drive constant voltage lines
in 8/4-ohm mode. Being able to use lower constant volt­age levels can be very convenient if building codes or
other obstacles do not permit higher constant voltage
levels. When 8/4-ohm mode is used to drive a distrib-

8 / 4 O H M

MIXER

Com-Tech Amplifier

DUAL 8/4 OHM MODE
(BOTH CHANNELS)

PARALLEL

MONO

PUSH TO RESET

P

R

R

E

E

S

S

S

T

E

CHANNEL 1

CHANNEL 2

REMOTE

DUAL

BB

Programmable
Input Processor (P.I.P.)

910

8

11

13

7

6

15

5

17

4

19

3

21

2

25

1

32

.5

0

dB

CH-2 CH-1

TURN OFF THE AMPLIFIER

BRIDGE

MONO

THE DUAL/MONO SWITCH.

CH2 CH1

+– +–

BEFORE CHANGING

8/4

OHM

910

8

11

13

7

6

15

5

17

4

19

3

21

2

25

1

32

.5

0

dB

Fig. 3.4 Wiring for Dual 8/4-Ohm Mode

CH2

70

8/4

VOLT

OHM

CH1

TURN OFF THE AMPLIFIER

70

BEFORE CHANGING THE

VOLT

OUTPUT MODE SWITCHES.

+

CHANNEL 1

CHANNEL 2

–

LOUDSPEAKERS

–

+

Reference Manual

Page 15

Com-Tech Power Amplifiers

uted loudspeaker system, the constant voltage output
varies with the output power rating of the amplifier. With
8/4-ohm output in Dual or Parallel-Mono mode, the
Com-Tech 210 can drive a 25-volt line, the Com-Tech
410 can drive a 35-volt line, the Com-Tech 810 can drive
a 50-volt line, and the Com-Tech 1610 can drive a 70­volt line. Using Bridge-Mono mode, these voltage lev­els are doubled for a single channel. Again, to
effectively use different constant voltage levels, you may
need to cross reference the ratings for the step-down
transformers’ taps using Crown’s constant voltage com­puter (see Section 8.3).

D U A L

Dual mode allows each amplifier channel to operate in­dependently like a “dual mono” or stereo amplifier. And
if you select both Dual mode and 70-volt output, each
output channel can drive a 70-volt line. Installation is
intuitive: Input Channel 1 feeds output channel 1, and
input Channel 2 feeds output Channel 2.

To put the amplifier into Dual mode, turn it off, slide the
dual/mono switch to the DUAL

(center) position, and

properly connect the output wiring. Be sure to observe

correct loudspeaker polarity (see Figure 3.4) and be
careful not to short the two outputs.

CAUTION: Never tie an amplifier’s outputs together
directly while in dual mode. Never parallel them with
the output of another amplifier.

Such connections do
not result in increased output power, but may cause
overheating and premature activation of the protection
circuitry.

Note: To parallel multiple amplifiers for fail-safe redun­dancy, contact Crown’s Technical Support Group.

B R I D G E - M O N O

Bridge-Mono mode is used to drive loads with a total
impedance of at least 8 ohms (see

Parallel-Mono

if the
load is less than 4 ohms). If Bridge-Mono mode and 70­volt output are used together, twice the normal output
voltage is produced from a single channel to drive 140­volt distributed loudspeaker systems. If you will be us­ing 140-volt output, you may need to cross-reference
the ratings of the step-down transformer taps with
Crown’s constant voltage computer (see Section 8.3). If
you need a single channel with higher power to drive a
70-volt line, use Parallel-Mono mode.

MIXER

Com-Tech Amplifier

DUAL 70 VOLT MODE
(BOTH CHANNELS)

Page 16

PARALLEL

MONO

PUSH TO RESET

P

R

R

E

E

S

S

S

T

E

CHANNEL 1

CHANNEL 2

REMOTE

DUAL

BB

Programmable
Input Processor (P.I.P.)

910

8

11

13

7

6

15

5

17

4

19

3

21

2

25

1

32

.5

0

dB

CH-2 CH-1

TURN OFF THE AMPLIFIER

BRIDGE

MONO

THE DUAL/MONO SWITCH.

CH2 CH1

+– +–

BEFORE CHANGING

8/4

OHM

910

8

11

13

7

15
17
19
21
25

32

.5

0

dB

Fig. 3.5 Wiring for Dual 70-Volt Mode

70

8/4

VOLT

OHM

CH2

6
5

4
3
2

1

CH1

CHANNEL 1

70 VOLT LINE

CHANNEL 2

TURN OFF THE AMPLIFIER

70

BEFORE CHANGING THE

VOLT

OUTPUT MODE SWITCHES.

+

COM

70 VOLT STEP-DOWN

TRANSFORMERS

COM

+

16, 8, OR 4 OHM

16, 8, OR 4 OHM

+

–

LOUDSPEAKERS

–

+

Reference Manual