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