Crown POWER BASE 1, POWER BASE 2, POWER BASE 3 User Manual

™

POWER

OFF

POWER

OFF

E106377

®

Applies only to 120 VAC,

North American PB-1,

PB-2 and PB-3 units.

OFF

Models:

Power Base-1, 2 & 3

© 1996 by Crown International, Inc., P.O. Box 1000, Elkhart, Indiana
46515-1000 U.S.A. Telephone: [phone]. Power-Tech amplifiers
are produced by the Professional Audio Division of Crown
International, Inc. Trademark Notice:
and

Power Base-1®, Power Base-2®, Crown

Power Base-3

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

™

is a trademark

®

,®

IOC

and

ODEP

®

are

POWER

LL 32521C

®

Applies only to 120 VAC,

North American PB-1

and PB-2 units.

101229-1

12/96

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. All expenses in
remedying the defect, including surface shipping costs to the nearest
authorized service center, will be borne by us. (You must bear the expense
of all taxes, duties and other customs fees when transporting the product.)

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 you need special assistance beyond the scope of this manual, please contact our Technical Support
Group.

Crown Audio Division 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] Fax Back: 800-294-4094 (North America only) or 219-293-9200

Internet: http://www.crownintl.com

IMPORTANT

THE POWER BASE-3 REQUIRES CLASS 1

OUTPUT WIRING. THE POWER BASE-1 AND

2 REQUIRE CLASS 2 OUTPUT WIRING.

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 BACK PANEL

COVER 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’ENLEVER LA

COVERTURE 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.

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.

Power Base Series Power Amplifiers

CONTENTS

1 Welcome .......................................................................... 7

1.1 Unpacking ................................................................. 7

1.2 Features .................................................................... 7

2 Installation ....................................................................... 9

2.1 Stereo ........................................................................ 9

2.2 Mono ......................................................................... 9

2.3 Input Sensitivity Adjustment...................................... 10

2.4 Additional Load Protection ....................................... 10

2.5 Required AC Mains .................................................. 10

3 Operation ....................................................................... 11

3.1 Precautions .............................................................. 11

3.2 Power Indicator ........................................................ 11

3.3 Protection Systems................................................... 11

3.3.1

ODEP ............................................................

3.3.2 Ultrasonic and RF Protection .......................... 11

3.3.3 Drive Protection ............................................. 11

3.3.4 Transformer Thermal Protection ..................... 12

3.3.5 Fuses and Circuit Breakers ............................ 12

3.4 Controls ................................................................... 12

3.5 Filter Cleaning .......................................................... 12

4 Specifications ................................................................ 13

5 Accessories ................................................................... 19

5.1 MT-XLR .................................................................... 19

5.2 MT-BB ..................................................................... 19

6 Service ........................................................................... 20

6.1 Worldwide Service ................................................... 20

6.2 North American Service ........................................... 20

6.2.1 Service at a North American Service Center ... 20

6.2.2 Factory Service .............................................. 20

11

Page 4

Power Base Series Power Amplifiers

1.1 Power Base Front and Back Panels .................................... 7

2.1Three System Connection Methods ....................................... 8

2.2Do NOT Block Air Flow .......................................................... 9

2.3Power Base Input Wiring ....................................................... 9

2.4Input Sensitivity Switch ........................................................ 10

2.5Loudspeaker Fuse Nomograph ........................................... 10

3.1Back Panel Level Controls ................................................... 12

4.1Power Base-1 Minimum Power Matrix .................................. 15

4.2Power Base-2 Minimum Power Matrix .................................. 16

4.3Power Base-3 Minimum Power Matrix .................................. 16

4.4Power Base-1 Maximum Power Matrix ................................. 17

4.5Power Base-2 Maximum Power Matrix ................................. 18

4.6Power Base-3 Maximum Power Matrix ................................. 18

5.1The MT-XLR ........................................................................ 19

5.2The MT-BB .......................................................................... 19

ILLUSTRATIONS

Page 5

Power Base Series Power Amplifiers

Page 6

Power Base Series Power Amplifiers

p

Power

Indicator

Power

Switch

POWER

OFF

Access

Cover

CAUTION:
THIS COVER IS NECESSARY FOR
EFFICIENT COOLING OF THE AMPLIFIER.
REMOVE ONLY TO ACCESS GAIN SWITCH.

THIS AMPLIFIER IS EQUIPPED WITH SELECTABLE INPUT SENSITIVITY. REMOVE COVER PLATE (ABOVE) TO ACCESS SENSITIVITY SWITCH.

CH-2

567

4

8
9

3

BALANCED

10

2

INPUT WIRING

MONO

1

11

+

TIP

0

12

INPUT

RING

–

GAIN

SLEEVE

GND

Ch.2

Ch.2

¼ Inch

Level

Phone

Control

Input

(Power Base–3 Only)

MODEL: POWER-BASE™ 3 12.5 AMPS
AC VOLTS: 120 60 Hz

MAXIMUM OUTPUT: 700 WATTS
PER CHANNEL INTO 4 OHMS AT 1 KHz
WITH NO MORE THAN 0.1% THD.

®

INTERNATIONAL, INC.

ELECTRONIC EQUIPMENT

ELKHART, IN 46517
MADE IN U.S.A.

000000

SERIAL NUMBER

WARNING:

TO
REDUCE THE RISK OF
FIRE OR ELECTRIC
SHOCK, DO NOT EXPOSE
THIS EQUIPMENT TO
RAIN OR MOISTURE.

REG. U.S. PAT. OFF.

4,330,809
4,611,180

0000

Reset

Switch

PUSH TO RESET

T

E

S

S

S

E

E

R

P

R

STEREO

PARALLEL

MONO

CAUTION:

TURN OFF AMPLIFIER

BEFORE CHANGING THIS SWITCH!

Stereo/Mono

Switch

Power

Cord

BRIDGE

Fig. 1.1 Power Base Front and Back Panels

1 Welcome

Congratulations on choosing a

Power Base

amplifiers are compact, professional ste­reo power amplifiers engineered to meet the most de­manding sound reinforcement needs. They compare
very favorably to more expensive amplifiers, providing
uncolored sound and signal-to-noise ratios commonly
associated with recording studios.

This manual will help you successfully install and use
your amplifier—we strongly recommend you read all
instructions, warnings and cautions. If you plan to oper­ate in one of the two mono modes, be sure to read Sec­tion 2.2. Also for your protection, please 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
with the carrier for damage resulting during shipment.
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.

Power Base

amplifier.

Removable grille

and dust filter

INPUT GROUND LIFT

LIFT

(AFFECTS PHONE INPUTS ONLY.)

Ground

Lift

Switch

INPUT

(MONO)

Ch.1
¼ Inch
Phone

In

CH-1

567

4
3
2

1

0

12

GAIN

Ch.1

Level

Control

ut

8

9

UNBALANCED

10

INPUT WIRING

11

GND

5-Way Binding Post

Output Connectors

OUTPUTS

CLASS 2
OUTPUT
WIRING

REQUIRED.

BRIDGE-MONO WIRING

1

TURN AMPLIFIER OFF.

2

SET STEREO/MONO
SWITCH TO
BRIDGE-MONO.

3

OUTPUT ACROSS
RED TERMINALS

+

TIP

ONLY. (CH-1
IS POSITIVE.)

SLEEVE

CH-2 CH-1

–

+

CAUTION:

SHOCK DO NOT REMOVE TOP OR BOTTOM
COVERS. NO USER SERVICEABLE PARTS
INSIDE. REFER SERVICING TO QUALIFIED
SERVICE PERSONNEL. DISCONNECT POWER
CORD BEFORE REMOVING REAR COVER
PLATE TO ACCESS SENSITIVITY SWITCH.

ATTENTION:

D'OUVRIR.

PARALLEL-MONO WIRING

1

TURN AMPLIFIER OFF.

2

SET STEREO/MONO SWITCH
TO PARALLEL-MONO.

3

ADD JUMPER (14
GAGE OR LARGER)
ACROSS RED TERMINALS.

4

OUTPUT ACROSS CH-1
TERMINALS ONLY.

TO PREVENT ELECTRIC

DÉBRANCHER AVANT

+

–

1.2 Features

❏ Rugged, professional power amplifier built for the road.

Mounts in a standard 19 inch (48.3 cm) rack.

❏ Crown’s patented

grounded bridge

ates large voltage swings while avoiding electrical
stress on the output stages. This results in low distortion
and high reliability.

❏ Front panel power switch with turn-on delay for loud-

speaker protection.

❏ Patented Output Device Emulation Protection (

keeps the amplifier working when others would fail.

❏ High damping factor provides superior control over low

frequency drivers for a clean, accurate low end.

❏ Safe with any load. Bridge-Mono and Parallel-Mono

modes offer optimal load-matching performance.

❏ Complete protection against shorted outputs, mis-

matched loads, overheating, DC input/output and high­frequency overload; full internal fault protection.

❏ Balanced phone jack inputs with internal three-position

sensitivity switch. Optional XLR or barrier block input
connectors are available with the
cessories.

❏ Ground lift switch is provided to isolate the chassis

ground from the phone jack input ground.

❏ Efficient heat sinks and self-contained forced air cool-

ing system dissipate heat quickly and evenly for extra
amplifier protection and greater power output.

❏ Three year “No-Fault” full warranty and guaranteed

specifications protect your investment.

circuitry gener-

MT-XLR

or

ODEP

MT-BB

ac-

®

)

Page 7

Power Base Series Power Amplifiers

CHANNEL 2

MIXER

STEREO MODE

MIXER

BRIDGE-MONO MODE

POWER BASE AMPLIFIER

PARALLEL

MONO

CAUTION:

BEFORE CHANGING THIS SWITCH.

POWER BASE AMPLIFIER

PARALLEL

MONO

CAUTION:

BEFORE CHANGING THIS SWITCH.

CHANNEL 1

CHANNEL 2

BRIDGE

MONO

CHANNEL 2 IS

NOT USED IN

THIS MODE.

CH-2 CH-1

CONTROL

CH-2 CH-1

STEREO

BRIDGE

PARALLEL

MONO

MONO

STEREO

TURN OFF AMPLIFIER

ONLY USE THE CHANNEL 1 INPUT

STEREO

BRIDGE

PARALLEL

MONO

MONO

STEREO

BRIDGE

MONO

TURN OFF AMPLIFIER

CH.2

GROUND

LEVEL

LIFT

SWITCH

TURN CHANNEL 2

OFF (FULLY CCW)

IN THIS MODE.

CH.1

LEVEL

CONTROL

DO NOT

USE BLACK

TERMINALS

–

+

LOUDSPEAKERS

+

–

CHANNEL 1

–

+

LOUDSPEAKER

MIXER

PARALLEL-MONO MODE

Page 8

POWER BASE AMPLIFIER

PARALLEL

MONO

CAUTION:

BEFORE CHANGING THIS SWITCH.

Fig. 2.1 Three System Connection Methods

ONLY USE THE CHANNEL 1 INPUT

CHANNEL 2 IS

NOT USED IN

THIS MODE.

STEREO

BRIDGE

PARALLEL

MONO

MONO

CH-2 CH-1

STEREO

BRIDGE

MONO

TURN OFF AMPLIFIER

ADD A 14 GAUGE

(OR LARGER)

JUMPER BETWEEN

THE RED CHANNEL 1

AND CHANNEL 2

BINDING POSTS.

+

–

LOUDSPEAKER

Power Base Series Power Amplifiers

2 Installation

Always remove power from the unit and turn the level
controls off (fully counterclockwise) when making or
breaking connections. This reduces the chance of
blasts that can cause loudspeaker damage.

The guidelines below are provided to help you quickly
get your amplifier installed and ready to go. Be sure to
follow the instructions in Sections 2.1 and 2.2 for the
selected mode of operation. Additional information on
input sensitivity, load protection and required AC
mains is provided in Sections 2.3, 2.4 and 2.5.

1. Install the amplifier in a standard 19 inch (48.3 cm) rack
or place it on a stable surface. The mounting dimensions
are 19 inches (48.3 cm) wide, 3.5 inches (8.9 cm) tall
and 16 inches (40.6 cm) deep behind the mounting sur­face. IMPORTANT! Allow for adequate ventilation.

17 in

43.2 cm

IMPORTANT: Be sure the back of

the amplifier is supported.

AIR

FLOW

16 in

40.6 cm

2 in

MIN.

AMPLIFIER

(TOP VIEW)

AIR FLOW

Fig. 2.2 Do NOT Block Air Flow

2. Use high-quality loudspeaker cables to connect the load
to the amplifier’s outputs. Do not use shielded cable.

3. Use shielded cables to connect audio sources to the
amplifier inputs. Either balanced or unbalanced wiring
can be used as shown below. (XLR connectors are avail­able with the MT-XLR accessory. See Section 5.)

1

2

INPUT

3

+

BALANCED

GND

–

+

PREAMPLIFIER

–

SHIELD

FROM

UNBALANCED

1

SHIELD

3

2

+

INPUT

+

SHIELD

AIR

FLOW

RACK

CABINET

FROM

PREAMPLIFIER

2.1 Stereo

1. Turn down the level controls (fully counterclockwise) and
turn off the amplifier.

2. Set the back panel stereo/mono switch to Stereo.

3. If present, remove the Parallel-Mono jumper.

4. Connect the input and output cables as shown in the first
example in Figure 2.1.

5. Turn on the amplifier and adjust the level for each chan­nel using the back panel level controls.

CAUTION: Never parallel the two outputs by di­rectly tying them together, and never parallel them
with the output of another amplifier.

2.2 Mono

Your amplifier’s mono modes provide double the
power of Stereo mode in a single channel. In Bridge­Mono mode, the outputs are wired in series for twice
the output voltage. In Parallel-Mono mode, the outputs
are paralleled for twice the current capacity.

Bridge-Mono mode is provided for loads with an im­pedance greater than 4 ohms. Parallel-Mono mode
should be used with loads of 4 ohms or less.

B R I D G E - M O N O

1. Turn down the level controls (fully counterclockwise) and
turn off the amplifier.

2. Set the back panel stereo/mono switch to Bridge-Mono.

3. If present, remove the Parallel-Mono jumper.

4. Connect the input and output cables as shown in the sec­ond example in Figure 2.1. Only use the channel 1 input.

5. Make sure the load is balanced (neither side shorted to
ground) and do not use the black (–) binding posts.

6. Turn on the amplifier and adjust the level. Only use the

channel 1 level control.

P A R A L L E L - M O N O

1. Turn down the level controls (fully counterclockwise) and
turn off the amplifier.

2. Set the back panel stereo/mono switch to Parallel-Mono.

3. Install a solid, 14-gauge (2 mm2) or heavier jumper wire
across the two red (+) binding post outputs.

4. Connect the input and output cables as shown in the third
example in Figure 2.1. Only use the channel 1 input.

5. Turn on the amplifier and adjust the level. Only use the

channel 1 level control.

CAUTION: With Parallel-Mono wiring, do not switch
to Stereo or Bridge-Mono mode until the output
jumper wire is removed.

Fig. 2.3 Power Base Input Wiring

Page 9

Power Base Series Power Amplifiers

2.3 Input Sensitivity Adjustment

The input sensitivity switch inside the amplifier is set to

0.775 volts at the factory. It can be changed to 1.4 volts
or a voltage gain of 26 dB as follows:

1. Turn off and unplug the amplifier from the AC source.

2. Remove the access cover on the back panel.

3. Locate the labeled access hole for the sensitivity switch.

4. Set the switch to the desired position.

5. Replace the access cover plate.

CH-1

®

567

4
3
2

1

0

GAIN

requires a

8

9

UNBALANCED

10

INPUT WIRING

11

+

12

TIP

SLEEVE

GND

When set to 26 dB gain, the

2.0 volt input, the
put and the

Power Base-2

Power Base-3

Power Base-1

®

requires a 2.5 volt in-

™

requires a 3.2 volt input to

deliver full output into an 8 ohm load.

SENSITIVITY SWITCH INSIDE ACCESS HOLE

1.4 V

26 dB

THIS AMPLIFIER IS EQUIPPED WITH SELECTABLE INPUT SENSITIVITY. REMOVE COVER PLATE (ABOVE) TO ACCESS SENSITIVITY SWITCH.

BALANCED

INPUT WIRING

+

TIP

RING

–

SLEEVE

GND

CH-2

567

4

8

9

3

10

2

1

11

0

12

GAIN

Fig. 2.4 Input Sensitivity Switch

0.77 V

INPUT

INPUT GROUND LIFT

LIFT

(AFFECTS PHONE INPUTS ONLY.)

INPUT

(MONO)

Example: (A) Find the peak music power of your loudspeaker
(such as 75 watts). (B) Find the loudspeaker impedance (8
ohms). (C) Draw a line between points A and B. The line inter­sects the middle scale at the correct fuse value (1.5 amps).

1.0

1.2

1.4

1.6

2

2.5

3

4

5

6

Example:

7

8

9

10

12

14

16

20

25

30

40

Impedance = 8 ohms.

Peak Power = 75 W

Answer: Fuse = 1.5 A

(ohms)

LOUDSPEAKER IMPEDANCE

FUSE

(amps)

20

15

10

8

6

5

4

3

2

1.5

1

.8

.6

.5

.4

.3

.2

.15

.1

.08

3000

2000

1500

1000
800

600

400

300

200

150

100
80

60

40

30

20

15

10
8

6

4

3

LOUDSPEAKER RATING

PEAK MUSIC POWER

2

1.5

1

(Typically 4 times the continuous average power)

(watts)

2.4 Additional Load Protection

To protect against excessive power, a fuse can be
added in series with each loudspeaker cable. A single
fuse can protect the entire system, or one can be used
for each driver. High-frequency drivers (tweeters) are
usually more sensitive to large voltage peaks, while
low-frequency drivers (woofers) are typically most sen­sitive to the heat from average (RMS) output power. To
protect your tweeters, we recommend that you use a
high-speed instrument fuse like the Littlefuse 361000
series. To protect your woofers, we recommend using a
slow-blow fuse that more closely represents the thermal
response of your woofer. Use Figure 2.5 to find the cor­rect value for either type of fuse.

Page 10

Fig. 2.5 Loudspeaker Fuse Nomograph

2.5 Required AC Mains

All

Power Base

priate line cord and plug. When possible, use a power
receptacle on a dedicated circuit, and always make
sure it will provide the right voltage and sufficient cur­rent. We do not recommend operating your amplifier
with voltages greater than 10% above or below the
unit’s rated voltage. For example, if your amplifier is
rated for 120 VAC, the line voltage should not exceed
132 VAC.

amplifiers are shipped with an appro-

Power Base Series Power Amplifiers

3 Operation

3.1 Precautions

Although your amplifier is protected from external faults,
the following safety precautions are recommended:

1. There are important differences among the Stereo,
Bridge-Mono and Parallel-Mono operating modes.
Please refer to Sections 2 for additional information.

2. WARNING: Do not change the position of the
stereo/mono switch unless the amplifier is first
turned off.

3. CAUTION: In Parallel-Mono mode, a jumper is
used to connect the red binding post outputs.
Be sure to remove this jumper for Bridge-Mono
or Stereo mode, or high distortion and excessive
heating will occur. Also, make sure the stereo/

mono switch is set to the proper position.

4. Use care when making connections, selecting sig­nal sources and controlling the output level. The
load you save may be your own!

5. Do not short the ground lead of an output cable to
the input signal ground. This will form a ground loop
and may cause oscillations.

6. Operate the amplifier from AC mains of not more
than 10% variation above or below the selected line
voltage and only at the specified line frequency.

7. Never connect the output to a power supply out­put, battery or power main. Such connections

may result in electrical shock.

8. Tampering with the circuitry by unqualified person­nel or making unauthorized circuit changes may be
hazardous and invalidates all agency listings.

Remember: Crown is not liable for any damage that re­sults from overdriving other system components.

3.2 Power Indicator

When lit, the amber power indicator (to the left of the
power switch) shows that the amplifier has been turned
on. It is driven only by the low-voltage power supply
and does not indicate the status of the high-voltage
supplies.

3.3 Protection Systems

Power Base

tems, including
protection, transformer thermal protection and fuses or
circuit breakers that protect the power supplies.

amplifiers have extensive protection sys-

ODEP

, ultrasonic/RF protection, drive

3.3.1

ODEP

Crown invented
under demanding conditions and to increase output
efficiency. To do this, Crown established a rigorous pro­gram to measure each transistor’s
(SOA). Intelligent circuitry was then designed to simu­late the instantaneous conditions of the output transis­tors. Its name describes what it does: Output Device
Emulation Protection, or
compares transistor conditions to their known SOA. If
more power will be asked of them than they can deliver
under the existing conditions,
until conditions fall within the SOA. Limiting is propor­tional and kept to an absolute minimum—only what is
required to prevent output transistor damage. Under
normal conditions, no limiting is required and
transparent to the audio signal.

ODEP

makes possible a quantum leap in output effi-

ciency and reliability—with

3.3.2 Ultrasonic and Radio Frequency Protection

An amplifier’s slew rate only needs to be large enough
to deliver the maximum voltage at the highest required
frequency. Higher slew rates actually allow undesirable
ultrasonic and radio frequencies to be reproduced. By
design,
rate to limit the highest frequencies that they reproduce.
Limiting occurs well above 20 kHz so there is no au­dible effect on performance. This approach protects
the amplifier from radio frequencies and can even pro­tect some sensitive loads (including some tweeters).

3.3.3 Drive Protection

The drive protection system temporarily removes output
drive to protect the amplifier and its loads. Drive protec­tion can be activated in two situations. First, if dangerous
subsonic frequencies or direct current (DC) is detected
in the amplifier’s output, the unit will activate its DC/low­frequency protection circuitry which puts the amplifier in
drive protection mode. This protects the loads and pre­vents oscillations. The unit resumes normal operation as
soon as the amplifier no longer detects dangerous out­put. Although it is extremely unlikely that you will ever
activate the amplifier’s DC/low frequency protection
system, improper source materials like subsonic square
waves or input overloads that excessively clip the input
signal can activate this system.

The amplifier’s fault protection system will put the am­plifier in drive protection mode in rare situations where
heavy common-mode current is detected in the output.

Power Base

ODEP

to keep the amplifier working

safe operating area

ODEP

. In simple terms,

ODEP

limits the drive

ODEP

, the show goes on.

amplifiers have a controlled slew

ODEP

ODEP

is

Page 11

Power Base Series Power Amplifiers

The unit should never output heavy common-mode cur­rent unless its circuitry is damaged. Activating drive
protection helps prevent further damage.

3.3.4 Transformer Thermal Protection

All

Power Base

amplifiers have transformer thermal
protection. This protection circuitry is activated in un­usual situations where the unit’s transformer tempera­ture rises to unsafe levels. Under these abnormal
conditions, the unit removes power to the high-voltage
transformer. The fan will continue to run in all units ex­cept those with 220/240 VAC transformers. The ampli­fier will return to normal after it cools to a safe
temperature.

It is very unlikely that your

Power Base

amplifier will
ever activate transformer thermal protection as long as
it is operated within rated conditions. Your amplifier is
designed to continue operating under conditions
where other amplifiers would fail. But even when you
exceed the limits of a

Power Base

amplifier, it still pro-

tects itself—and your investment—from damage.

3.3.5 Fuses and Circuit Breakers

All 120 VAC, 60 Hz units and all

Power Base-3

units
have a fuse that protects the low-voltage power supply
and cooling fan. The

Power Base-1

and

Power Base-2

high-voltage power supplies are protected by fuses,
while the

Power Base-3

high-voltage power supplies
are protected by a circuit breaker. With rated loads
and output levels, these fuses (or the circuit breaker)
should only shut down the amplifier in the incredibly
rare instance of a catastrophic amplifier failure. The

ODEP

protection system keeps the amplifier opera­tional under most other severe conditions. The fuses
(or breaker) can also shut down the amplifier in situa­tions where extremely low-impedance loads and high
output levels result in excessive current draw.

A

Power Base

amplifier will not blow its fuses or trip its
breaker unless something is wrong. In the rare event
that an internal fuse blows, please refer the unit to a
qualified technician. If the breaker in a

Power Base-3

trips, try to identify and correct the problem before re­setting it with the back panel Circuit Breaker Reset. If
the problem persists, refer the unit to a qualified techni­cian.

3.4 Controls

The Power switch is th only control located on the front
panel. All others are located on the rear, including the
level controls.

When making any setup or wiring changes, don’t forget
to turn off the amplifier, turn down the level controls and
disconnect the power cord. Be sure to turn down (full
counterclockwise) the channel 2 level control when us­ing either mono mode. The Parallell Mono/Stereo/
Bridge Mono switch is used to select Stereo, Bridge­Mono or Parallel-Mono operating modes. The Input
Ground Lift switch isolates the phone jack input
grounds from the chassis ground to help prevent
ground loops. It does not affect any installed input ac­cessories. The Input Sensitivity Switch, located inside
the back cover plate, sets the amplifier’s input sensitiv­ity (refer to subsection 2.3 for information on changing
this switch). And the

Power Base-3

has a back panel
Circuit Breaker Reset button that resets the circuit
breaker (refer to subsection 3.3.5).

CHANNEL 2

LEVEL CONTROL

CH-2

567

4

8

9

3

10

2

1

11

0

12

GAIN

INPUT GROUND LIFT

INPUT

LIFT

(AFFECTS PHONE INPUTS ONLY.)

INPUT

(MONO)

Fig. 3.1 Back Panel Level Controls

CHANNEL 1

LEVEL CONTROL

CH-1

567

4

8

9

3

10

2

1

11

0

12

GAIN

3.5 Filter Cleaning

A dust filter is provided on the unit’s air intake. If it be­comes clogged, the unit will cool less efficiently and
may produce lower output levels. To clean the filter,
use a phillips screwdriver to remove the three screws
the secure the front grille. Use mild dishwashing deter­gent and warm water for best cleaning results. Be sure
the filter is dry before you reinstall it. Replacement fil­ters may be ordered from the factory.

Dust filters are not 100% efficient—long term this may
require internal heat-sink cleaning by a qualified tech­nician. Internal cleaning information is available from
our Technical Support Group.

Page 12

Power Base Series Power Amplifiers

4 Specifications

All specifications apply to units in Stereo mode with 8-ohm loads
and an input sensitivity of 26 dB unless otherwise specified.

Standard 1 kHz Power: refers to maximum average power in
watts at 1 kHz with 0.1% THD+ noise.

Full Bandwidth Power: refers to maximum average power in
watts from 20 Hz to 20 kHz with 0.1% THD+ noise.

120 VAC, 60 Hz Units: refers to amplifiers with dedicated trans­formers for 120 VAC, 60 Hz power mains.

Performance

Frequency Response: ±0.1 dB from 20 Hz to 20 kHz
at 1 watt.

Phase Response: ±10 degrees from 10 Hz to 20 kHz
at 1 watt.

Signal-to-Noise: A-weighted, better than 105 dB be­low full bandwidth power. Better than 100 dB below full
bandwidth power from 20 Hz to 20 kHz.

Total Harmonic Distortion (THD): Less than 0.05%
at full bandwidth power from 20 Hz to 1 kHz increas­ing linearly to 0.1% at 20 kHz.

Intermodulation Distortion (IMD): (60 Hz and 7 kHz
4:1) Less than 0.05% from less than 158 milliwatts to full
bandwidth power.

Damping Factor: Greater than 1,000 from 10 Hz to 400 Hz.
Crosstalk

Power Base-1

width power from 50 Hz to 2 kHz, rising linearly to
greater than 60 dB at 20 kHz.

Power Base-2

width power from 50 Hz to 2 kHz, rising linearly to
greater than 66 dB at 20 kHz.

Power Base-3

width power from 50 Hz to 4 kHz, rising linearly to
greater than 70 dB at 20 kHz.

Common Mode Rejection (CMR): Better than 70 dB
below rated full bandwidth power from 20 Hz to 1 kHz
falling linearly to better than 50 dB at 20 kHz.

Controlled Slew Rate: Greater than 13 volts/ms.

Voltage Gain: 20:1 ±3% or 26 dB ±0.25 dB at the maxi-

mum level setting (Input Sensitivity switch set to its 26
dB position).

Power Base-1

volt sensitivity; 28:1 ±12% or 29.1 dB ±1 dB at 1.4 volt
sensitivity.

: Greater than 75 dB below full band-

: Greater than 90 dB below full band-

: Greater than 90 dB below full band-

: 51:1 ±12% or 34.3 dB ±1 dB at 0.775

Power Base-2

: 64:1 ±12% or 36.2 dB ±1 dB at 0.775
volt sensitivity; 35:1 ±12% or 31.0 dB ±1 dB at 1.4 volt
sensitivity.

Power Base-3

: 83:1 ±12% or 38.4 dB ±1 dB at 0.775
volt sensitivity; 46:1 ±12% or 33.3 dB ±1 dB at 1.4 volt
sensitivity.

Power

Output Power:

teed minimums for standard 1 kHz power. For more infor­mation, see the power matrices in Figures 4.1 through 4.6
(maximum average power @ 0.1% THD + N).

Power Base-1

Stereo mode (both channels driven):

Bridge-Mono mode:

Parallel-Mono mode:

Power Base-2

Stereo mode (both channels driven):

Bridge-Mono mode:

Parallel-Mono mode:

Power Base-3

Stereo mode (both channels driven):

Bridge-Mono mode:

1525 watts into 8 ohms.
1090 watts into 16 ohms.

Parallel-Mono mode:

1530 watts into 2 ohms.
1080 watts into 4 ohms.

Load Impedance: Safe with all types of loads. Rated
for 4 to 8 ohms in Stereo, 8 to 16 ohms in Bridge­Mono and 2 to 4 ohms in Parallel-Mono mode.

The following specifications are guaran-

240 watts into 4 ohms.
200 watts into 8 ohms.

455 watts into 8 ohms.
395 watts into 16 ohms.

455 watts into 2 ohms.
400 watts into 4 ohms.

460 watts into 4 ohms.
325 watts into 8 ohms.

910 watts into 8 ohms.
660 watts into 16 ohms.

920 watts into 2 ohms.
655 watts into 4 ohms.

760 watts into 4 ohms.
540 watts into 8 ohms.

Page 13

Power Base Series Power Amplifiers

Required AC Mains: Current, frequency and voltage

requirements are provided on each unit’s back panel.
All models draw 90 watts or less at idle.

Power Base-1

Power Base-2

Power Base-3

Low-Voltage Power Supply: A ±24 VDC fanformer
supply (fan motor winding) regulated to ±15 VDC.

AC Connector: An appropriate AC line cord and plug
are provided. 120 VAC, 60 Hz units have a standard
3-wire, 15-amp grounded connector (NEMA 5-15P).

: Draws up to 6 amps of current.

: Draws up to 10 amps of current.

: Draws up to 15 amps of current.

Controls

Power: A front panel rocker switch used to turn the
amplifier on and off.

Level: A back panel rotary potentiometer for each chan­nel used to control the output level.

Stereo/Mono: A three-position back panel switch used
to select Stereo, Bridge-Mono or Parallel-Mono mode.

Sensitivity: A three-position switch inside the back
cover plate used to select the input sensitivity for both
channels: 0.775 volts or 1.4 volts for standard 1 kHz
power, or 26 dB voltage gain (see Section 2.3).

Input Ground Lift: A two-position back panel switch
used to isolate the phone jack and chassis grounds.

Reset (

ton used to reset the circuit breaker that protects the
power supplies.

Power Base-3

only): A back panel push but-

Indicators

Power: This amber indicator shows the on/off status of
the low voltage power supply.

Input/Output

Input Connector: Balanced ¼ inch phone jacks. See
Section 5 for XLR and barrier block accessories.

Input Impedance: Nominally 20 K ohms, balanced;
10 K ohms, unbalanced.

Output Connector: Two sets of color-coded 5-way bbinding
posts (for banana plugs, spade lugs or bare wire).

Output Impedance: Less than 10 milliohms in series
with less than 2 microhenries.

DC Output Offset: Less than 10 millivolts.

Output Signal

Stereo: Unbalanced, two-channel.

Bridge-Mono: Balanced, single-channel. Channel 1

controls are active; Channel 2 controls should be
turned down and not used.

Parallel-Mono: Unbalanced, single-channel. Channel
1 controls are active; Channel 2 controls should be
turned down and not used.

Protection

Power Base

open or mismatched loads; overloaded power supplies;
excessive temperature, chain destruction phenomena,
input overload and high-frequency blowups. They also
protect loudspeakers from input and output DC, as well
as providing protection from turn-on/turn-off transients.

If operating conditions are unreasonable, the patented

ODEP

tect the output transistors, particularly in the case of el­evated temperature. A thermal switch imbedded in the
transformer protects the power supplies from overload.
In the rare event that a transformer overheats, the ther­mal switch removes power, waits until the unit has cooled
to a safe temperature and then resets itself.

Turn On: Four second delay with no dangerous tran­sients. Contact us if you need to change the delay.

amplifiers are protected against shorted,

circuitry proportionally limits the drive level to pro-

Construction

Durable black finish on steel chassis with special “flow­through” ventilation from front to side panels.

Cooling: Internal heat sinks with forced-air cooling
for rapid, uniform heat dissipation.

Dimensions: Standard 19-inch (48.3 cm) rack mount
width (EIA RS-310-B), 3.5-inch (8.9 cm) height and
16-inch (40.6 cm) depth behind the mounting surface.

Approximate Weight: Center of gravity is 6 inches
(15.2 cm) behind front mounting surface.

120 VAC, 60 Hz Units:

Power Base-1

(15.4 kg) shipping weight.

Power Base-2

(17.2 kg) shipping weight.

Power Base-3

(18.2 kg) shipping weight.

: 30 pounds (13.6 kg) net; 34 pounds

: 34 pounds (15.4 kg) net; 38 pounds

: 36 pounds (16.3 kg) net; 40 pounds

Page 14

Power Base Series Power Amplifiers

Crown specifications are guaranteed for three years.

In an effort to provide you with as much information as possible about the high power-producing capabilities of your amplifier, we have
created the following power matrices.

Minimum Power Specifications

Crown’s minimum power specifications represent the absolute smallest amount of output power you can expect from your amplifier when it
is driven to full output under the given conditions. Some spaces in each matrix may be left blank because the same guarantee is not
provided for those conditions—however, your amplifier will perform well under all conditions listed in each matrix.

When measuring power, 0.1% THD appears to be the industry standard for distortion. Two of the maximum average power specifications
shown in each minimum power matrix are measured at 0.1% THD so you can easily compare Crown specifications to those of other manu­facturers. But this high level of distortion actually allows for some clipping which is undesirable. Because of this, a maximum average power
spec at 0.05% THD is included in each minimum power matrix which represents non-clipped conditions. Although most manufacturers do
not give you power specifications at 0.05% THD, we encourage them to provide these specifications so you will have a more realistic
representation of the way amplifiers should be used in the real world—without a clipped output signal.

Many manufacturers publish power specs with a tolerance of ±1 dB or worse. This means their amplifier can deviate more than 20% in
output! A 100 watt amplifier would meet their specification if it only produced 79.4 watts. Other manufacturers qualify their specs by saying
they are “typical,” “subject to manufacturing tolerances,” “single channel driven” or that they are specified with “fuses bypassed.” Each of
these statements effectively removes any performance guarantee. In fact, some manufacturers use these tactics to generate large power
numbers, and they don’t even print a disclaimer. We take a different approach at Crown—our amplifiers are
their specifications for three years. Further, because our published specs are set below our “in-house” measurements, you can expect
Crown amplifier to

Minimum Power Notes:

All minimum power specifications are based on 0.1% regulated AC mains and an ambient room temperature of 70° F (21° C). A 100V, 50Hz model was used
because of its higher current demand. The standard EIA power measurement (RS-490) is not identified here because it is identical to the FTC Continuous
Average Power specification.

1. A 1 kHz sine wave is presented to the amplifier and the output monitored for nonlinear distortion. The level is increased until the THD reaches 0.1%. At this level
the average power per channel is reported.

2. A sine wave is presented to the amplifier over the range from 20 Hz to 20 kHz and the output monitored for nonlinear distortion. The level at each frequency is
increased until the THD reaches 0.1%. At this level the average power per channel is reported.

3. A 1 kHz sine wave is presented to the amplifier and the output monitored for nonlinear distortion. The level is increased until the THD reaches 0.05%. At this
level the average power per channel is reported.

4. Continuous power in the context of Federal Trade Commission testing is understood to be a minimum of five minutes of operation. Harmonic distortion is
measured as the RMS sum total and given as a percentage of the fundamental output voltage. This applies for all wattages greater than 0.25 watts.

exceed

its published minimum power specs. We believe you should get what you pay for.

guaranteed

to meet or exceed

every

Power Base-1 – Minimum Guaranteed Power (Watts)

Stereo-Mono

Mode

AC Mains120 VAC, 60 Hz Units

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

Parallel-Mono

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

International Units

Parallel-Mono

Fig. 4.1 Power Base-1 Minimum Power Matrix

0.1% THD+N
(See note 1)

Load (Ohms)

4
8
8

16

2

4
4
8
8

16

2

4

Maximum Average

1 kHz

240

200

455

395

455

400

230

205

465

410

440

410

0.1% THD+N
(See note 2)

20Hz-20kHz

175

185

360

370

165

185

355

375

0.05% THD+N
(See note 3)

1 kHz

235

200

455

390

445

395

225

200

455

405

430

405

FTC Continuous Average

0.1% THD + Noise
(See note 4)

1 kHz 20Hz-20kHz

200

390

390

200

390

390

180

350

175

350

Page 15

Power Base Series Power Amplifiers

Power Base-2 –

Stereo-Mono

Mode

AC Mains120 VAC, 60 Hz Units

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

Parallel-Mono

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

International Units

Parallel-Mono

Fig. 4.2 Power Base-2 Minimum Power Matrix

0.1% THD+N
(See note 1)

Load (Ohms)

4
8
8

16

2

4
4
8
8

16

2
4

Minimum Guaranteed Power (Watts)

Maximum Average

1 kHz

460

325

910

660

920

655

425

310

855

620

850

620

0.1% THD+N
(See note 2)

20Hz-20kHz

425

310

830

615

390

290

775

575

0.05% THD+N
(See note 3)

1 kHz

460

325

905

655

915

650

425

305

850

615

845

615

FTC Continuous Average

0.1% THD + Noise
(See note 4)

1 kHz 20Hz-20kHz

385

310

815

625

805

630

395

305

790

615

785

610

265

530

325

275

640

545

Power Base-3 –

Stereo-Mono

Mode

AC Mains120 VAC, 60 Hz Units

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

Parallel-Mono

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

International Units

Parallel-Mono

Fig. 4.3 Power Base-3 Minimum Power Matrix

0.1% THD+N
(See note 1)

Load (Ohms)

4
8
8

16

2

4
4
8
8

16

2
4

Minimum Guaranteed Power (Watts)

Maximum Average

1 kHz

760

540

1525

1090

1530

1080

680

510

1335

1025

1365

1015

0.1% THD+N
(See note 2)

20Hz-20kHz

1430

1045

1240

715

525

630

495

980

0.05% THD+N
(See note 3)

1 kHz

755

540

1500

1075

1520

1080

660

505

1305

1000

1340

1010

FTC Continuous Average

0.1% THD + Noise
(See note 4)

1 kHz 20Hz-20kHz

530

1055

1065

555

510

1115

1025

1115

1030

495

985

485

470

1085

930

Page 16

Power Base Series Power Amplifiers

Maximum Power Specifications

Crown’s maximum power specifications represent the largest amount of output power you can expect from your amplifier when it is driven to
full output under the given conditions. These specifications can be used to prevent loudspeaker and hearing damage.

The maximum power matrices include specifications for single cycle and 40 millisecond burst sine waves. Burst signals act like large
transient peaks that are present in common source signals. Loudspeakers can respond to a single cycle burst, so the single cycle burst
specifications should be used to help you protect your loudspeakers. In contrast, a 40 millisecond burst represents the typical response time
of the human ear. Your ear will not respond to the entire dynamic change of a burst that lasts less than 40 milliseconds.

The specifications are provided at 0.05% THD because this represents a low distortion condition. To help you operate your amplifier within
these tolerances, Crown’s premium amplifiers include an input/output comparator that shows when the amplifier has exceeded 0.05% THD.
Operating the amplifier at levels higher than 0.05% THD can result in output power levels that are higher than those listed in the maximum
power matrices.

Maximum Power Notes:

All maximum power specifications are based on 0.1% regulated AC mains and an ambient room temperature of 70° F (21° C). A 100V, 50Hz model was used
because of its higher current demand. Although it is an unusual condition, your amplifier can function well with AC mains voltages up to 10% over the specified
line voltage. With overvoltage conditions, your amplifier may be capable of delivering instantaneous power levels up to 20% greater than the specifications in the
matrix.

1. A single cycle sine wave is presented to the amplifier and monitored for nonlinear distortion. The average power during the burst is reported. Loudspeakers
must be able to withstand this level if they are to be safely used with this amplifier.

2. A 40 millisecond sine wave burst (10 percent duty cycle) is presented to the amplifier and monitored for nonlinear distortion. The average power during the
burst is reported. This power level is a measurement of the amplifier’s maximum transient power that can be perceived by the human ear.

Stereo-Mono

Mode

AC Mains120 VAC, 60 Hz Units

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

Parallel-Mono

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

International Units

Parallel-Mono

Fig. 4.4 Power Base-1 Maximum Power Matrix

Load (Ohms)

4
8
8

16

2
4
4
8
8

16

2

4

Power Base-1 –

Single Cycle Tone Burst

At less than 0.05% THD

(See note 1)

50 Hz

325

265

630

540

635

530

325

290

640

580

620

580

1 kHz

335

310

640

630

645

615

330

345

650

690

625

690

Maximum Power (Watts)

40 Millisecond Tone Burst

0.05% THD + Noise
(See note 2)

7 kHz 50 Hz

335

300

620

610

640

600

330

335

670

670

625

670

315

230

600

470

620

465

320

260

635

520

615

515

1 kHz 7 kHz

295

220

565

440

580

430

315

235

625

470

615

475

310

230

580

455

605

450

330

250

655

495

625

490

Page 17

Power Base Series Power Amplifiers

Stereo-Mono

Mode

AC Mains120 VAC, 60 Hz Units

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

Parallel-Mono

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

International Units

Parallel-Mono

Power Base-2 –

Single Cycle Tone Burst

At less than 0.05% THD

(See note 1)

Load (Ohms)

50 Hz

655

4

460

8

1410

8

915

16

1440

2

915

4
4

720

8

465

8

1440

16

920

2

1390

4

915

Maximum Power (Watts)

1 kHz

805

525

1850

1060

1685

1055

900

530

1770

1055

1670

1055

7 kHz 50 Hz

790

515

1805

1020

1645

1020

885

510

1785

1020

1655

1015

40 Millisecond Tone Burst

0.05% THD + Noise
(See note 2)

550

400

1190

795

1185

805

605

410

1200

820

1185

820

Fig. 4.5 Power Base-2 Maximum Power Matrix

1 kHz 7 kHz

500

375

1090

755

1085

750

545

380

1075

750

1065

750

520

395

1125

780

1120

775

565

395

1120

785

1110

775

Stereo-Mono

Mode

AC Mains120 VAC, 60 Hz Units

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

Parallel-Mono

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

International Units

Parallel-Mono

Power Base-3 –

Single Cycle Tone Burst

Load (Ohms)

50 Hz

1090

4

715

8

2155

8

1415

16

2140

2

1420

4

4

1190

8

785

8

2355

16

1540

2

2330

4

1570

At less than 0.05% THD

(See note 1)

Maximum Power (Watts)

1 kHz

1575

870

3140

1740

3135

1735

1750

960

3490

1915

3485

1895

7 kHz 50 Hz

1525

838

3040

1675

3015

1665

1695

920

3380

1840

3345

1825

40 Millisecond Tone Burst

0.05% THD + Noise
(See note 2)

910

610

1780

1250

1790

1225

970

675

1945

1360

1940

1360

Fig. 4.6 Power Base-3 Maximum Power Matrix

1 kHz 7 kHz

815

570

1615

1135

1605

1135

870

625

1725

1235

1720

1235

855

595

1690

1180

1680

1170

920

645

1805

1285

1800

1270

Page 18

Power Base Series Power Amplifiers

5 Accessories

There are two accessories available at the time of this
printing: the

MT-XLR

Factory Service Center or the Crown factory.

5.1 MT-XLR

The

MT-XLR

standard 3-pin female XLR input connectors. The

MT-XLR

connections in a system that uses standard XLR con­nectors. It can also be used in systems that need to
daisy chain an input signal from one amplifier to an-

MT-XLR

and

MT-BB

and the

MT-BB

. Important: The

must be installed at a Crown

is an accessory panel that provides two

accessory makes it easy to quickly change

other. Because the

MT-XLR

connectors are wired in
parallel with the amplifier’s built in phone jack connec­tors, an input signal fed to either input can be fed to
another amplifier from the unused connector for that
channel.

5.2 MT-BB

The

MT-BB

is an accessory panel that provides barrier
strip input connectors. An
desirable in applications requiring bare wire connec­tions. It can also be used to daisy chain an input signal
from one amplifier to another just like the

MT-BB

accessory might be

MT-XLR

.

MT-XLR

CH-2 INPUT CH-1 INPUT

PUSHPUSH

THESE XLR INPUTS ARE CONNECTED IN PARALLEL WITH THE PHONE JACK INPUTS.

Fig. 5.1 The MT-XLR

MT-BB

3

GND

12

CH-2 INPUT CH-1 INPUT

Fig. 5.2 The MT-BB

– +– +

Page 19

6 Service

This unit has very sophisticated circuitry which should
only be serviced by a fully trained technician. This is
one reason why each unit bears the following label:

CAUTION: To prevent electric shock, do not re­move covers. No user serviceable parts inside. Re­fer servicing to a qualified technician.

6.1 Worldwide Service

Service may be obtained from an authorized service
center. (Contact your local Crown/Amcron representa­tive or our office for a list of authorized service centers.)
To obtain service, simply present the bill of sale as
proof of purchase along with the defective unit to an
authorized service center. They will handle the neces­sary paperwork and repair.

Remember to transport your unit in the original factory
pack. We will pay the surface shipping costs both
ways for warranty service to the authorized service
center nearest you after receiving copies of all ship­ping receipts. You must bear the expense of all taxes,
duties, and customs fees when transporting the unit.

6.2 North American Service

Service may be obtained in one of two ways: from an
authorized service center or from the factory. You may
choose either. It is important that you have your copy of
the bill of sale as your proof of purchase.

6.2.1 Service at a North American Service Center

This method usually saves the most time and effort.
Simply present your bill of sale along with the defective
unit to an authorized service center to obtain service.
They will handle the necessary paperwork and repair.
Remember to transport the unit in the original factory
pack. A list of authorized service centers in your area
can be obtained from our Technical Support Group.

6.2.2 Factory Service

To obtain factory service, fill out the service informa­tion page that follows and send it along with your proof

of purchase and the defective unit to the Crown factory.
For warranty service, we will pay for ground shipping
both ways in the United States after receiving copies of
the shipping receipts. Shipments should be sent “UPS
ground.” (If the unit is under warranty, you may send it
C.O.D. for the cost of freight via UPS ground.) The fac-

Power Base Series Power Amplifiers

tory will return it via UPS ground. Please contact us if
other arrangements are required.

Factory Service Shipping Instructions:

Always use the
original factory pack
to transport the unit.

1. When sending a Crown product to the factory for
service, be sure to fill out the service information
form that follows and enclose it inside your unit’s
shipping pack. Do not send the service informa­tion form separately.

2. To ensure the safe transportation of your unit to
the factory, ship it in an original factory packing
container. If you don’t have one, call or write
Crown’s Parts Department. With the exception of
polyurethane or wooden crates, any other pack­ing material will not be sufficient to withstand the
stress of shipping. Do not use loose, small size

packing materials.

3. Do not ship the unit in any kind of cabinet (wood
or metal). Ignoring this warning may result in ex­tensive damage to the unit and the cabinet. Ac­cessories are not needed—do not send the
instruction manual, cables and other hardware.

If you have any questions, please call or write the
Crown Technical Support Group.

Crown Audio Division

Technical Support / Factory Service
Plant 2 SW, 1718 W. Mishawaka Rd., Elkhart,
Indiana 46517 U.S.A.

Telephone:

Facsimile:

Fax Back:

Internet:

219-294-8200
800-342-6939 (North America,

Puerto Rico, and Virgin Islands only)

219-294-8301 (Technical Support)
219-294-8124 (Factory Service)

219-293-9200
800-294-4094 (North America only)

http://www.crownintl.com

Page 20

Power Base Series Power Amplifiers

Crown Factory Service Information

Shipping Address: Crown International, Inc., Factory Service, Plant 2 SW, 1718 W. Mishawaka Rd., Elkhart, IN 46517

Phone: [phone] or 1-219-294-8200 Fax: [phone]

Owner’s Name: _________________________________________________________________________
Shipping Address: ______________________________________________________________________
Phone Number: _____________________________ Fax Number: _____________________________

Model: ________________________ Serial Number:______________ Purchase Date: ___________

NATURE OF PROBLEM

(Be sure to describe the conditions that existed when the problem occurred and what attempts were made to correct it.)

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________

Detach and send with unit.

______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________

Other equipment in your system: _________________________________________________________

______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________

If warranty has expired, payment will be:

Card Number:___________________________ Exp. Date:_______ Signature:____________________________

❏ ❏

❏ Cash/Check

❏ ❏

❏❏

❏ VISA

❏❏

❏❏

❏ MasterCard

❏❏

❏❏

❏ C.O.D.

❏❏

ENCLOSE THIS PORTION WITH THE UNIT. DO NOT MAIL SEPARATELY.

Page 21