Crown DC-300-A-2, DC-300-A Mk2 Owners manual

DC-300A II

®

Applies only to
120 VAC North

American units.

POWER

CHANNEL 1 CHANNEL 2I0C

30

40

50

0

Some models may be exported under the name

© 1996 by Crown International, Inc., P.O. Box 1000, Elkhart, Indiana
46515-1000 U.S.A. Telephone: [phone]. The DC-300A II is
produced by the Professional Audio Division of Crown International,
Inc. Trademark Notice:

®

System

and

Macro-Tech

Amcron®, Crown

®

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

®

,

Com-Tech

20

10

Amcron

®

,

IOC

30

40

20

50

10

0

®

.

®

,

IQ

K80002D9

5/96

3

YEAR

THREE YEAR

FULL W ARRANTY

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 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 Audio Division Technical Support Group

57620 C.R. 105, 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

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 QUALI-

FIED SERVICE PERSONNEL.

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.

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.

DC-300A II Power Amplifier

CONTENTS

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

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

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

2 Facilities ............................................................................ 8

3 Installation ......................................................................... 9

3.1 Mounting ..................................................................... 9

3.2 Cooling........................................................................ 9

3.3 Wiring ......................................................................... 9

3.3.1 Mode of Operation ............................................ 9

3.3.2 Input Connection ............................................. 11

3.3.3 Output Connection. ..... .................................... 12

3.3.4 Additional Load Protection .............................. 13

3.3.5 AC Mains Power Requirement......................... 14

4 Operation......................................................................... 15

4.1 Precautions ............................................................... 15

4.2 Indicators .................................................................. 15

4.3 Controls..................................................................... 15

4.4 Protection .................................................................. 15

4.5 Fuse Replacement .................................................... 16

5 Technical Information ..................................................... 17

5.1 Principles of Operation .............................................. 17

6 Specifications ................................................................. 18

7 Internal Settings .............................................................. 23

7.1 26 dB Gain vs. 0.775 V Input Sensitivity .................... 23

7.2 Changing the Input Sensitivity to 0.775 V................... 23

8 Service............................................................................. 24

8.1 Worldwide Service ..................................................... 24

8.2 North American Service............................................. 24

8.2.1 Service at a North American Service Center .. . 24

8.2.2 Factory Service ............................................... 24

Page 4

DC-300A II Power Amplifier

1.1 DC-300A II................................................................................7

2.1 Facilities....................................................................................8

3.1 Mounting Dimensions ...............................................................9

3.2 System Connection.................................................................10

3.3 Input Wiring ............................................................................11

3.4 Subsonic Filter Capacitors ......................................................11

3.5 Unbalanced RFI Filters ...........................................................11

3.6 Balanced RFI Filters................................................................ 11

3.7 Wire Size Nomograph .............................................................12

3.8 Inductive Load (Transformer) Network ....................................13

3.9 Fuse Selector Nomograph ...................................................... 14

3.10 AC Mains Voltage Conversion................................................. 14

5.1 Circuit Block Diagram ............................................................. 16

6.1 Power Matrix ...........................................................................19

6.2 Nominal Output Impedance....................................................20

6.3 Nominal Output Phase Angle ..................................................20

6.4 Nominal Damping Factor ........................................................20

6.5 Nominal Phase Response .......................................................21

6.6 Nominal Crosstalk...................................................................21

6.7 Nominal Power Efficiency........................................................21

6.8 Nominal Noise Spectrum ........................................................22

6.9 Nominal Frequency Response ................................................22

7.1 Main Circuit Board ..................................................................23

ILLUSTRATIONS

Page 5

DC-300A II Power Amplifier

Rev. 0

Page 6

DC-300A II Power Amplifier

POWER

Fig. 1.1 DC-300A II

1 Welcome

Congratulations on purchasing a Crown DC-300A II.
Y our amplifier is designed to provide r eliable operation
with a variety of loads. It is a versatile choice for use in
studios, laboratories, public facilities and on the road.
And the sonic excellence of the DC-300A II makes it a
very good choice for your personal listening pleasure.

Using innovative circuitry, the DC-300A II yields ultra­low distortion through a wide range of frequencies from
DC (0 Hz) to 20 kHz. The amplifier’s output transistors
are “direct coupled” to the load so there are no output
capacitors or transformers to compromise its superb
sonic integrity. The tremendous output power of the
DC-300A II enables it to deliver balanced 70 volt out­put in Bridge-Mono mode without using costly “step­up” transformers. And Crown’s innovative JTS
(Junction Temperature Simulation) circuitry dynami­cally adjusts the output protection system for unparal­leled sonic headroom. Crown further protects your
investment with the industry’s only thr ee year “No-Fault”
full warranty. After reading this manual and learning
about the features, facilities and capabilities of your
amplifier , you will understand why Crown amplifiers ar e
recognized as the worldwide standard for audio excel­lence.

For your protection, please send in your warranty reg­istration card and save your bill of sale, as it is your

official proof of purchase.

CHANNEL 1 CHANNEL 2I0C

30

40

20

50

10

0

30

40

20

50

10

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diately . Only you 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.

1.2 Features

Y our dual channel (ster eo) amplifier can be configur ed
for higher-powered single channel operation. It also
provides the following features:

❏ AB+B class circuitry for maximum efficiency with mini-

mum crossover “notch” distortion.

❏

❏ Ultra-low harmonic and intermodulation distortion result

❏ Very low noise level and wide dynamic range exceed

❏ Exclusive JTS (Junction Temperature Simulation) cir-

❏ High damping factor gives you greater loudspeaker mo-

❏ Bridge-Mono output can drive 70 volt “constant voltage”

®

IOC

(Input/Output Comparator) alerts of distortion ex-

ceeding 0.05% to provide

proof of performance

.

in the best dynamic transfer function in industry.

digital audio standards.

cuitry protects the output devices and provides excep­tional dynamic headroom.

tion control.

lines without expensive, distortion-producing “step-up”
transformers.

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 imme-

❏ Convection cooling with integrated heat sink/chassis de-

sign for maintenance-free operation.

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

ment and guarantees the specifications of units in North
America and other select countries.

Page 7

DC-300A II Power Amplifier

POWER

A B D G H H GFC C E D I

OUTPUT

CHANNEL 2

2 INPUT 1 LINE

DUAL MONO

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

SERIAL NUMBER

Fig. 2.1 Facilities

2 Facilities

A. Power Indicator

This indicator glows when the amplifier is turned on.

B. Power Switch

This push button turns the DC-300A II on and off. The
unit has no turn-on delay and minimal thumps. Always
turn the amplifier on last so the turn-on transients of
other components will not be amplified.

C. Input Jacks

An unbalanced ¼ inch phone jack is used for input to
each channel. Do not use the channel 2 input in Bridge­Mono mode.

D. Output Jacks

5-way binding posts provide output from each chan­nel. Use banana plugs, spade lugs or bare wire to con­nect loudspeaker cables. In Bridge-Mono mode,
connect the positive (+) loudspeaker terminal to the
positive (+) channel 1 output and the negative (–) loud­speaker terminal to the positive (+) channel 2 output.

E. Dual-Mono Switch

Facing the back of the amplifier , slide this switch to the
left for Dual (stereo) mode and to the right for Bridge-

CHANNEL 1 CHANNEL 2I0C

®

ELECTRONIC EQUIPMENT

000000

INTERNATIONAL, INC.

OUTPUT

CHANNEL 1

FUSE AC

0000

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40

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30

40

20

10

50

0

Mono mode. In Bridge-Mono mode, the channel 2 in­put should not be used, its level control should be
turned down and only balanced (ungrounded) loads
should be connected to the output (see section 3.3.1).

F. Fuse Holder

The AC line is safely fused. Use a 10 amp, 250 volt,
type AB fuse for 100 and 120 VAC operation, or a
5 amp, 250 volt, type MTH fuse for 200, 220 and
240 VAC units (see Sections 3.3.5 and 4.5).

G. Level Controls

The output level of each channel is adjusted with these
controls. Turn the channel 2 level control down com­pletely when using Bridge-Mono mode.

H. Power Cord

The unit has a grounded, three wire AC cor d and plug.

I.

IOC

Indicators

The red Input/Output Comparator (
vide

proof of distortion-free performance

they flash in the rare event that the output waveform
differs from the input by 0.05% or more.

IOC

) indicators pro-

. Normally off,

Page 8