Crown Audio MA-24X6, MA-36X12 User Manual

Operation Manual

Macro-Tech Series

MA-24X6

MA-36X12

Obtaining Other Language Versions:

local Crown Distributor. If you need assistance locating your local distributor, please contact Crown at 574-294-8000.
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.

Note:

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

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

Trademark Notice:

tem, and P.I.P. are registered trademarks of Crown International. Other trademarks are the property of their respective owners.

©2003 by Crown Audio, Inc. P.O. Box 1000, Elkhart, Indiana 46515-1000 U.S.A. Telephone: [phone]

SmartAmp, Grounded Bridge and PIP are trademarks and Amcron, Crown, Macro-Tech, IOC, ODEP, IQ, IQ Sys-

To obtain information in another language about the use of this product, please contact your

Some models may be exported under the name Amcron.

®

125782-5

6/03

Important Safety Instructions

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

1) Read these instructions.

2) Keep these instructions.

3) Heed all warnings.

4) Follow all instructions.

5) Do not use this apparatus near water.

6) Clean only with a dry cloth.

7) Do not block any ventilation openings. Install
in accordance with the manufacturer’s instruc­tions.

8) Do not install near any heat sources such as
radiators, heat registers, stoves, or other
apparatus that produce heat.

9) Do not defeat the safety purpose of the polar­ized or grounding-type plug. A polarized plug
has two blades with one wider than the other.
A grounding-type plug has two blades and a
third grounding prong. The wide blade or the
third prong is provided for your safety. If the
provided plug does not fit into your outlet,
consult an electrician for replacement of the
obsolete outlet.

10) Protect the power cord from being walked on
or pinched, particularly at plugs, convenience
receptacles, and the point where they exit from
the apparatus.

11) Only use attachments/accessories specified by the manufacturer.

12) Use only with a cart, stand, bracket, or table
specified by the manufacturer, or sold with the
apparatus. When a cart is used, use caution
when moving the cart/apparatus combination
to avoid injury from tip-over.

13) Unplug this apparatus during lightning storms or when unused for long periods of time.

14) Refer all servicing to qualified service person­nel. Servicing is required when the apparatus
has been damaged in any way, such as power­supply cord or plug is damaged, liquid has
been spilled or objects have fallen into the
apparatus, the apparatus has been exposed to
rain or moisture, does not operate normally,
or has been dropped.

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

TO PREVENT ELECTRIC SHOCK DO NOT REMOVE
TOP OR BOTTOM COVERS. NO USER SERVICE­ABLE PARTS INSIDE. REFER SERVICING TO
QUALIFIED SERVICE PERSONNEL.

À PRÉVENIR LE CHOC ÉLECTRIQUE N’ENLEVEZ
PAS LES COUVERCLES. IL N’Y A PAS DES PAR­TIES SERVICEABLE À L’INTÉRIEUR. TOUS REPA­RATIONS DOIT ETRE FAIRE PAR PERSONNEL
QUALIFIÉ SEULMENT.

IMPORTANT

MA Series amplifiers require Class 2 output wiring.

MAGNETIC FIELD

CAUTION! Do not locate sensitive high-gain equip­ment such as preamplifiers or tape decks directly
above or below the unit. Because this amplifier has
a high power density, it has a strong magnetic field
which can induce hum into unshielded devices that
are located nearby. The field is strongest just above
and below the unit.

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

WATCH FOR THESE SYMBOLS:

The lightning bolt triangle is used to alert the user
to the risk of electric shock.

The exclamation point triangle is used to alert the
user to important operating or maintenance instruc­tions.

FCC COMPLIANCE NOTICE

This device complies with part 15 of the FCC rules. Operation is subject to the following
two conditions: (1) This device may not cause harmful interference, and (2) this device
must accept any interference received, including interference that may cause undesired
operation.

CAUTION: Changes or modifications not expressly approved by the party responsible for
complicance could void the user’s authority to operate the euqipment.

NOTE: This equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference in a residential installation. This
equipment generates, uses, and can radiate radio frequency energy and, if not installed
and used in accordance with the instruction manual, may cause harmful interference to
radio communications. However, there is no guarantee that interference will not occur in a
particular installation. If this equipment does cause harmful interference to radio or televi­sion reception, which can be determined by turning the equipment off and on, the user is
encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.

• Increase the separation between the equipment and receiver.

• Connect the equipment into an outlet on a circuit different from that to which the
receiver is connected.

• Consult the dealer or an experienced radio/TV technician for help.

page 2

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

Crown International, Inc.

Issued By: Crown International, Inc.

1718 W. Mishawaka Road
Elkhart, Indiana 46517 U.S.A.

Competent Body’s Name and Address:

Technology International (Europe) Limited
41-42 Shrivenham Hundred Business Park,
Shrivenham, Swindon, Wilts, SN6 8TZ

Equipment Type: Commercial Audio Power Amplifiers
Family Name: Macro-Tech
Model Names: MA-24X6, MA-36X12

EMC Standards:

EN 55103-1:1995 Electromagnetic Compatibility - Product Family Standard for Audio, Video, Audio-Visual and Entertainment Lighting Control Apparatus for Professional Use, Part 1: Emissions
EN 55103-1:1995 Magnetic Field Emissions-Annex A @ 10 cm and 1 M
EN 61000-3-2:1995+A14:2000 Limits for Harmonic Current Emissions (equipment input current ≤16A per phase)
EN 61000-3-3:1995 Limitation of Voltage Fluctuations and Flicker in Low-Voltage Supply Systems Rated Current ≤16A
EN 55022:1992 + A1: 1995 & A2:1997 Limits and Methods of Measurement of Radio Disturbance Characteristics of ITE: Radiated, Class B Limits; Conducted, Class B
EN 55103-2:1996 Electromagnetic Compatibility - Product Family Standard for Audio, Video, Audio-Visual and Entertainment Lighting Control Apparatus for Professional Use, Part 2: Immunity
EN 61000-4-2:1995 Electrostatic Discharge Immunity (Environment E2-Criteria B, 4k V Contact, 8k V Air Discharge)
EN 61000-4-3:1996 Radiated, Radio-Frequency, Electromagnetic Immunity (Environment E2, criteria A)
EN 61000-4-4:1995 Electrical Fast Transient/Burst Immunity (Criteria B)
EN 61000-4-5:1995 Surge Immunity (Criteria B)
EN 61000-4-6:1996 Immunity to Conducted Disturbances Induced by Radio-Frequency Fields (Criteria A)
EN 61000-4-11:1994 Voltage Dips, Short Interruptions and Voltage Variation

Safety Standard:
EN 60065: 1998 Safety Requirements - Audio Video and Similar Electronic Apparatus

I certify that the product identified above conforms to the requirements of the EMC Council Directive 89/336/EEC as amended by 92/31/EEC, and the Low Voltage Directive 73/23/EES as amended by 93/68/EEC.

Signed

Larry Coburn

Title: Senior Vice President of Manufacturing

DECLARATION of CONFORMITY

Technical Construction File Route

TCF Technical Certificate No: P4300CRI1.IWS

Sue Whitfield
574-294-8289
[e-mail]

European Representative's Name and Address:

Nick Owen
19 Clos Nant Coslech
Pontprennau
Cardiff
CF23 8ND United Kingdom

Date of Issue: March 28, 2000

Operation Manual

DUE TO LINE CURRENT HARMONICS, WE RECOMMEND THAT YOU CONTACT YOUR SUPPLY AUTHORITY BEFORE CONNECTION.

page 3

Table of Contents

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

Important Safety Instructions .....................................................................................2

Declaration of Conformity ..........................................................................................3

1 Welcome ........................................................................ 5

1.1 Features .........................................................................................................5

1.2 How to Use This Manual ................................................................................5

2 Setup ............................................................................. 6

2.1 Unpack Your Amplifier ...................................................................................6

2.2 Install Your Amplifier .....................................................................................6

2.3 Ensure Proper Cooling .................................................................................6

2.4 Choose Input Wire and Connectors ..............................................................7

2.5 Choose Output Wire and Connectors .............................................................8

2.6 Wire Your System .........................................................................................9

2.7 Connect to AC Mains ...................................................................................10

2.8 Startup Procedure ........................................................................................10

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

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

3.2 Front Panel Controls and Indicators ............................................................ 12

3.3 Back Panel Controls and Connectors ........................................................... 13

4 Advanced Features and Options ............................................ 14

4.1 Protection Systems ......................................................................................14

4.1.1 Output Device Emulation Protection (ODEP) .......................................14

4.1.2 IOC (Input Output Comparator) ...........................................................14

4.1.3 Standby Mode ....................................................................................14

4.1.4 Transformer Thermal Protection ............................................... 15

4.1.5 Circuit Breakers ........................................................................ 15

4.2 Circuit Designs ................................................................................. 15

4.2.1 Grounded Bridge ...................................................................... 15

4.2.2 Variable Impedance (VZ) .......................................................... 15

4.3.1 PIP Modules ............................................................................ 16

4.3.2 IQ-PIP-USP2 Adapter ............................................................... 16

4.3.3 Input Sensitivity Switch ............................................................ 16

4.3.4 Input Ground Lift Switch ..........................................................16

5 Troubleshooting .......................................................... 17

5.1 Indicators ............................................................................................ 17

6 Theory of Operation ..................................................... 19

7 Specifications ............................................................21

8 AC Power Draw and Thermal Dissipation ............................24

9 Service .................................................................... 26

9.1 Worldwide Service.............................................................................. 26

9.2 US and Canada Service ....................................................................... 26

9.2.1 Service at a US or Canada Service Center................................ 26

9.2.2 Factory Service ........................................................................ 26

9.2.3 Factory Service Shipping Instructions: .....................................26

10 Warranty ................................................................27

Crown Factory Service Information Form ........................................................29

page 4

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

1 Welcome

Congratulations on your purchase of a Macro-

®

Tec h

dual level professional power amplifier.
Your amplifier has a separate high-power and
medium-power channel, making it ideal for
biamplified systems. The Macro-Tech 24x6
combines one channel of a Macro-Tech 2400
with one channel of a Macro-Tech 600. The
Macro-Tech 36x12 combines one channel of a
Macro-Tech 3600VZ with one channel of a
Macro-Tech 1200. And because each model
has a separate power supply for each channel,
each channel can be treated as a separate
power amplifier.

Because it’s a Macro-Tech, you have the added
benefit of PIP ™ compatibility for access to
custom input modules and ODEP
to keep the show going long after other amplifi­ers would fail.

Modern power amplifiers are sophisticated
pieces of engineering capable of producing
extremely high power levels. They must be
treated with respect and correctly installed if
they are to provide the many years of reliable
service for which they were designed.

In addition, MA-24X6 and MA-36X12 amplifi­ers include a number of features which require
some explanation before they can be used to
their maximum advantage.

Please take the time to study this manual so
that you can obtain the best possible service
from your amplifier.

®

protection

1.1 Features

•Crown’s Grounded Bridge™ design deliv-
ers incredible voltage swings without
using stressful output transistor configura­tions like conventional amplifiers. The
results are lower distortion and superior
reliability.

• Patented ODEP (Output Device Emulation
Protection) circuitry compensates for
overheating and overload to keep the
amplifier working long after others would
fail.

®

• IOC

• PIP connector accepts accessories that tai-

• Very low harmonic and intermodulation

• High damping factor provides superior

(Input/Output Comparator) circuitry
immediately alerts of any distortion
exceeding 0.05%, providing dynamic
proof of distortion-free performance.

lor the amplifier to suit specific applica­tions.

distortion give the best dynamic transfer
function in the industry.

control over low frequency drivers for a
clean, accurate low end.

• Full protection against shorted outputs,
open circuits, DC, mismatched loads, gen­eral overheating, high frequency overloads
and internal faults.

• Extra rugged, extruded aluminum front
panel with ODEP and Signal Presence/IOC
indicators for each channel, as well as an
Enable indicator.

• Macro-Tech 36x12: Articulated VZ power
supply for Channel 1 (3600) provides the
best power matching to your load.

• Efficient heat sinks and forced air cooling
prevent overheating and prolong compo­nent life.

• Balanced inputs with three-position sensi­tivity switch and adjustable front panel
level controls.

• 5-way binding post outputs provide versa­tile connection.

• Mounts in a standard 19-inch (48.3-cm)
equipment rack (units can also be
stacked).

• Three Year “No-Fault” Full Warranty com­pletely protects your investment and guar­antees its specifications.

1.2 How to Use This Manual

This manual provides you with the necessary
information to safely and correctly setup and
operate your amplifier. It does not cover every
aspect of installation, setup or operation that
might occur under every condition. For addi­tional information, please consult Crown’s
Amplifier Application Guide (available online at
www.crownaudio.com), Crown Tech Support,
your system installer or retailer.

We strongly recommend you read all instruc­tions, warnings and cautions contained in this
manual. Also, for your protection, please send
in your warranty registration card today. And
save your bill of sale—it’s your official proof of
purchase.

Operation Manual

page 5

2 Setup

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

2.1 Unpack Your Amplifier

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

We also recommend that you 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.YOU WILL NEED (not
supplied):

• Input wiring cables

• Output wiring cables
Rack for mounting amplifier (or a stable surface

for stacking)

WARNING: Before you start to set up
your amplifier, make sure you read and
observe the Important Safety Instruc­tions found at the beginning of this
manual.

2.2 Install Your Amplifier

CAUTION: Before you begin, make sure
your amplifier is disconnected from the
power source, with power switch in the
“off” position and all level controls
turned completely down (counterclock­wise).

Use a standard 19-inch (48.3 cm) equipment
rack. See Figure 2.1 for amplifier dimensions.

You may also stack amps without using a cabi­net.

NOTE: When transporting, amplifiers should be
supported at both front and back.

2.3 Ensure Proper Cooling

When using an equipment rack, mount units
directly on top of each other. Close any open
spaces in rack with blank panels. DO NOT
block front or rear air vents. The side walls of
the rack should be a minimum of two inches
(5.1 cm) away from the amplifier sides, and the
back of the rack should be a minimum of four
inches (10.2 cm) from the amplifier back panel.

Figure 2.2 illustrates standard amplifier airflow.

page 6

19 in

48.3 cm

SIDE VIEW

16 in

40.6 cm

Figure 2.1 Dimensions

2.5 in

6.35 cm

3.5 in

8.9 cm

Figure 2.2 Airflow

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

2 Setup

2.4 Choose Input Wire and Connectors

Figure 2.3 shows connector pin assignments for
balanced wiring, and Figure 2.4 shows connec­tor pin assignments for unbalanced wiring.

NOTE: Custom wiring should only be
performed by qualified personnel.

Balanced Line

Figure 2.3 Balanced Input

Connector Wiring

Unbalanced Line

Figure 2.4 Unbalanced Input

Connector Wiring

Operation Manual

page 7

2 Setup

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

2.5 Choose Output Wire and Con­nectors

Crown recommends using pre-built or profes­sionally wired, high-quality, two-conductor,
heavy gauge speaker wire and connectors. You
may use banana connectors, terminal forks or
bare wire for your output connectors (see Figure

2.5). To prevent the possibility of short-circuits,
wrap or otherwise insulate exposed loudspeaker
cable connectors.

Note: Binding post outputs on European
models come with safety plugs installed
to prevent European power-cord plugs
from being inserted. The side entry posi­tions for these connectors should there­fore be used on European models.

Using the guidelines below, select the appropri­ate size of wire based on the distance from
amplifier to speaker.

Distance Wire Size

up to 25 ft. 16 AWG

26-40 ft. 14 AWG
41-60 ft. 12 AWG

61-100 ft. 10 AWG
101-150 ft. 8 AWG
151-250 ft. 6 AWG

OUTPUTS

CH-2

CH-1

Figure 2.5 Output Connector Wiring

page 8

CAUTION: Never use shielded cable for
output wiring.

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

2 Setup

2.6 Wire Your System

This section describes the most common way to
install the Macro-Tech 24X6 and 36X12. Each
model is designed for biamplified systems and
includes both a high-power and a medium­power channel.

Because each channel produces a different
power level, the Macro-Tech 24x6 and 36x12 are
dedicated to two-channel operation. They do
NOT offer mono operation.

WARNING: Never strap the outputs
together for Parallel-Mono operation!
Never bridge the outputs for Bridge-Mono
operation!

Installation of the Macro-Tech 24x6 and 36x12 is
very intuitive. The Channel 1 input feeds the
Channel 1 output and the Channel 2 input feeds
the Channel 2 output. Be sure to connect the
output wiring as shown in Figure 2.6.

Five-way binding posts are provided to facilitate
easy connection of loudspeakers to each chan­nel. Note: Because of its higher output power,
Channel 1 of a Macro-Tech 36x12 has an addi­tional set of binding posts.

Observe correct loudspeaker polarity and be very
careful not to short the outputs of one channel to
the outputs of the other channel.

NOTE: Crown provides a reference of wiring pin
assignments for commonly used connector
types in the Crown Amplifier Application Guide
available at www.crownaudio.com.

Operation Manual

Figure 2.6 System Wiring (a Macro-Tech 36x12 is shown)

page 9

2 Setup

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

2.7 Connect to AC Mains

Connect the AC power cordset of your amplifier
to the AC mains power source (power outlet).

NOTE: The third prong of this connector
(ground) is an important safety feature. Do not
attempt to disable this ground connection by
using an adapter or other methods.

Amplifiers don’t create energy. The AC mains
voltage and current must be sufficient to deliver
the power you expect. You must operate your
amplifier from an AC mains power source with
not more than 10% variation above or below the
amplifier’s specified line voltage and within the
specfied frequency requirements (indicated on
the amplifier’s back panel label). If you are
unsure of the output voltage of your AC mains,
please consult your electrician.

2.8 Startup Procedure

Use the following procedure when first turning
on your amplifier:

1. Turn down the level of your audio source.

2. Turn down the level controls of the ampli­fier.

3. Turn on the “Enable” switch. The Enable
indicator should glow.

4. Turn up the level of your audio source to an
optimum level.

5. Turn up the Level controls on the amplifier
until the desired loudness or power level is
achieved.

6. Turn down the level of your audio source to
its normal range.

If you ever need to make any wiring or
installation changes, don’t forget to turn
off the amplifier and disconnect the
power cord.

For help with determining your system’s
optimum gain structure (signal levels)
please refer to the Crown Amplifier Appli-
cation Guide, available online at
www.crownaudio.com.

page 10

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

3 Operation

3.1 Precautions

Your Macro-Tech Series amplifier is protected
from internal and external faults, but you should
still take the following precautions for optimum
performance and safety:

1. Before use, your amplifier first must be con­figured for proper operation, including input
and output wiring hookup. Improper wiring
can result in serious operating difficulties.
For information on wiring and configura­tion, please consult the Setup section of this
manual or, for advanced setup techniques,
consult Crown’s Amplifier Application
Guide available online at www.crownau­dio.com.

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

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

4. Never connect the output to a power
supply, battery or power main. Elec­trical shock may result.

5. Tampering with the circuitry, or making
unauthorized circuit changes, may be haz­ardous and invalidates all agency listings.

6. Do not operate the amplifier with the Signal/
IOC LEDs constantly indicating an IOC con­dition.

7. Do not overdrive the mixer, which will cause
a clipped signal to be sent to the amplifier.
Such signals will be reproduced with
extreme accuracy, and loudspeaker damage
may result.

Operation Manual

page 11

3 Operation

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

3.2 Front Panel Controls and Indicators

A. Dust Filter

Removes large particles from the air at the
air intake. The filter elements can be easily
removed for cleaning by gently pulling
them away from the front panel.

B. Level Control

Rotary detented level control, one per
channel.

C. Signal/IOC Indicator

Green LED, one per channel. Dual-pur­pose indicator illuminates to indicate the
presence of input signals; flashes brightly
with a 0.1-second hold delay to indicate a
difference (distortion) between the input
and output signal of 0.05% or greater; and
flashes brightly with a 0.5-second hold
delay to indicate input clipping distortion.
See Section 4.1.2 for more about IOC.

D. ODEP Indicator

Red LED, one per channel, illuminates
brightly to indicate presence of thermody-

namic energy. They dim proportionally as
energy reserves decrease. In the event that
energy reserves are depleted, the indica­tors turn off and ODEP limiting occurs.
See Section 4.1 for more about ODEP.

E. Enable Indicator

Green LED indicates amplifier has been
turned on and AC power is available.

F. Enable Switch

Amplifier is on when the switch is in the IN
position.

page 12

Figure 3.1 Front Panel

Controls and Indicators

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

3 Operation

3.3 Back Panel Controls and Connectors

G. Power Cord

120 VAC, 60 Hz units have a 20-amp (12 AWG)

line cord with a grounded NEMA 5-15P plug.
See Section 8 for AC power usage.

H. Reset Switches

The reset switches are used to reset the break-

ers that safeguard each power supply from
overload.

I. PIP Module

The standard P.I.P.-FX is included with your

amplifier. It provides female XLR input connec­tors. A variety of other PIP modules can be

used in place of the P.I.P.-FX. They add addi­tional features that customize the amplifier for
different applications. For information on avail­able PIP modules visit the Crown website at
http://www.crownaudio.com.

Input Sensitivity Switch

The three-position input sensitivity switch

located inside the amplifier is accessed by
removing the PIP module (I). It is factory-set to

0.775 volts for rated 8 ohm output. It can also
be set to 1.4 volts for rated output, or a voltage
gain of 26 dB (see Section 4.3.3).

J. Balanced Phone Jack Inputs

Balanced ¼-inch phone jack input connectors

are provided on the back panel of your ampli­fier. The phone jacks can be wired for either

balanced (tip, ring and sleeve) or unbalanced
(tip and sleeve) input signals. Because they are
electrically in parallel with the PIP input con­nectors, input signals should not be connected
to the phone jacks when certain PIP modules
are installed (see the Crown Amplifier Applica-
tion Guide availabel online at www.crownau­dio.com). The phone jacks can also be used as
“daisy chain” outputs to simplify connecting
input signals to multiple amplifiers.

K. Ground Lift Switch

This switch isolates or “lifts” the phone jack

signal grounds from the AC power ground.
Activating the switch inserts an impedance
between the sleeve of each phone jack and the
unit’s AC ground to help prevent the hum that
can result from a ground loop.

L. Balanced XLR Inputs

The factory-installed P.I.P.-FX provides a three-

pin female XLR connector for balanced input to
each channel. The XLR inputs are connected in
parallel with the amplifier’s phone jack inputs.
Because the P.I.P.-FX does not have any active
circuitry, its XLR connectors can also be used
as “daisy chain” outputs to connect signals
from phone jack inputs to multiple amplifiers .

M. Output Jacks

A pair of versatile 5-way binding posts is pro-

vided for the output of each channel. The 5-way
binding posts accept banana plugs, spade lugs
or bare wire. Note: Because of its higher output

power, the Macro-Tech 36x12 has an additional
set of binding posts.

Operation Manual

Figure 3.2 Back Panel

Controls and Connectors

page 13

4 Advanced Features
and Options

NOTE: For detailed information about
these Crown amplifier features, please
consult the Crown Amplifier Application
Guide, available on the Crown website
at www.crownaudio.com

4.1 Protection Systems

Your Crown amplifier provides extensive pro­tection and diagnostic capabilities, including
ODEP, IOC., “standby” mode, fuses (or break­ers), and special thermal protection for the
unit’s transformers.

4.1.1 Output Device Emulation Protection (ODEP)

Crown invented ODEP to solve two long stand­ing problems in amplifier design: To prevent
amplifier shutdown during demanding opera­tion and to increase the efficiency of output cir­cuitry.

To do this, Crown established a rigorous pro­gram to measure the safe operating area (SOA)
of each output transistor before installing it in
an amplifier. Crown also designed intelligent
circuitry to simulate the instantaneous operat­ing conditions of those output transistors. Its
name describes what it does: Output Device
Emulation Protection or ODEP. It not only simu­lates the operation of the output transistors but
it also compares their operation to their known
SOA. If ODEP sees that more power is about to
be asked of the output devices than they are
capable of delivering under the present condi­tions, ODEP immediately limits the drive level
until it falls within the SOA. Limiting is propor­tional and kept to an absolute minimum—only
what is required to prevent the possibility of
output transistor damage.

This level of protection enables Crown to
increase output transistor utilization while
greatly increasing amplifier reliability.

Finally, this onboard intelligence is monitored
in two ways. First, the front panel ODEP indica­tors show whether the amplifier is functioning
correctly or if ODEP is limiting the drive level.
Second, ODEP data is fed to the PIP connector
at the back of the amplifier so advanced PIP
modules like the IQ-PIP-USP2 can use it to
make decisions and control the amplifier.

With ODEP you get the maximum power with
the maximum protection—the show goes on!

4.1.2 IOC (Input Output Compara­tor)

The IOC circuit compares the output signal of
the amplifier with the input signal. If there is
any difference other than gain, then it is consid­ered distortion and the indicator comes on. The
LED indicator will come on whenever there is
distortion of 0.05% or more. An IOC condition
may also be sensed by an IQ PIP module
installed in PIP-compatible amplifiers.

IOC is designed to report any form of distor­tion. IOC not only checks the waveform for dis­tortion, but also reports input overload and
even a protective action that mutes or shuts
down an amplifier. With all of these features,
IOC monitors the entire amplifier. When the IOC
indicator is off the amplifier is definitely opera­tional and undistorted. IOC provides an on-line
proof of performance.

4.1.3 Standby Mode

At the heart of the protection systems is the
standby mode which removes power from the

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

high-voltage supplies to protect the amplifier
and connected loads. The standby mode can be
identified using the indicator table in Figure

5.2.
Standby mode can be activated in several situa-

tions. 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 and put the
affected channels in standby. This protects the
loads and prevent oscillations. The unit
resumes normal operation as soon as the
amplifier no longer detects dangerous low fre­quency or DC output. Although it is extremely
unlikely that you will ever activate the ampli­fier’s DC/low-frequency protection system,
improper source materials such as subsonic
square waves or input overloads that result in
excessively clipped input signals can activate
this system.

The amplifier’s fault protection system will put
an amplifier channel in standby mode in rare
situations where heavy common-mode current
is detected in the channel’s output. The ampli­fier should never output heavy common-mode
current unless its circuitry is damaged in some
way, and putting a channel in standby mode
helps to prevent further damage.

The amplifier’s transformer thermal protection
circuitry is activated in very unusual circum­stances where the unit’s transformer tempera­ture rises to unsafe levels. Under these
abnormal conditions, the amplifier will put the
channel of the affected transformer in standby
mode. The amplifier will return to normal oper­ation after the transformer cools to a safe tem­perature. (For more information on transformer
thermal protection, refer to the following sec­tion.)

page 14

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

4 Advanced Features and Options

4.1.4 Transformer Thermal Protection

All Macro-Tech amplifiers have transformer
thermal protection. It protects the power sup­plies from damage under the rare conditions of
transformer temperatures rising too high. A
thermal switch embedded in each transformer
removes power to the channel if there is exces­sive heat. The switch automatically resets when
the transformer cools to a safe temperature.

It is very unlikely that you will ever see a
Macro-Tech amplifier activate transformer ther­mal protection as long as it is operated within
rated conditions (see Section 7, Specifica­tions). One reason is that ODEP keeps the
amplifier working under very severe conditions.
Even so, higher than rated output levels, exces­sively low impedance loads and unreasonably
high input signals can generate more heat in
the transformer than in the output devices.
These conditions can overheat the transformer
and activate its protection system.

Macro-Tech amplifiers are designed to keep
working under conditions where other amplifi­ers would fail. But even when its limits are
exceeded, it will still protect itself—and your
investment—from damage.

4.1.5 Circuit Breakers

The power supplies are protected by circuit
breakers. With rated loads and output levels,
the circuit breakers should only shut down the
amplifier in the rare instance of a catastrophic
failure. Other protection systems like ODEP
keep the amplifier operational under most other
severe conditions. The circuit breakers can also
shut down the amplifier in cases where
extremely low-impedance loads and high out­put levels result in current draw that exceeds
their rating. Again, this should only be possible
when operating outside rated conditions, like

when the amplifier is used to drive a 1-ohm
load in Stereo mode, or when a signal over­loads the input and is clipped severely.

Macro-Tech amplifiers do not trip their break­ers unless something is wrong. If a breaker
trips, try to identify and correct the problem
before resetting the breakers with the back
panel Reset switches. If the problem persists,
refer the unit to a qualified technician.

4.2 Circuit Designs

4.2.1 Grounded Bridge

Grounded Bridge is the name of Crown's
unique four-quadrant amplifier topology. The
Grounded Bridge topology takes full advantage
of the power supplies delivering peak-to-peak
voltages to the load that are twice the voltage
seen by the output devices and twice the volt­age generated by the power supplies.

The power supply bridge rectifier is not ground
referenced, and the transformer secondary is
not center-tapped. This allows the power sup­ply to deliver +VCC and -VCC from the same
bridge rectifier and filter as a total difference in
potential regardless of their voltages with
respect to ground.

Composite output devices are arranged to func­tion as gigantic NPN and PNP devices. Each
output stage has two composite NPN and two
composite PNP devices. The devices con­nected to the load are referred to as “high-side
NPN and PNP” and the devices connected to
ground are referred to as “low-side NPN and
PNP.” Positive current is delivered to the load
by increasing conductance simultaneously in
the high-side NPN and low-side PNP stage,
while decreasing conductance of the high-side
PNP and low-side NPN in synchrony.

Crown's Grounded Bridge design delivers large
voltage swings without stressing output tran­sistors. The results are higher efficiency, lower
distortion and superior reliablility.

4.2.2 Variable Impedance (VZ) (Macro-Tech 36X12 only)

VZ is the name of Crown's patented articulated
power supply technology. This innovative tech­nology permits us to pack large amounts of
power into a compact package while achieving
ultra-low distortion and without generating
excessive heat.

An amplifier power supply must be large
enough to handle both the maximum voltage
and maximum current necesary for the ampli­fier to drive its rated power into a specified
load. In order to meet this requirement, most
conventional supplies are heavy, large, and
produce lots of heat. In contrast, the VZ supply
gets more current AND voltage out of a smaller,
lighter, and more efficient package by dynami­cally adapting to both signal and load require­ments in real-time. This provides the best
power match to the widest range of loads.

The VZ supply is divided into two segments.
When the output stage requires high-voltage,
the segments are arranged in series to deliver
twice the voltage of a single segment. When the
output stage requires high-current, the seg­ments are arranged in parallel to deliver twice
the current of a single segment. Sensing cir­cuitry "watches" the voltage of the signal to
determine when to switch VZ modes. The
switching circuitry is designed to prevent audi­ble switching distortion to yield the highest
possible dynamic transfer function—you hear
only the music and not the amplifier.

With VZ, you get not only maximum power and
safety, but you also get the best power match­ing to your load.

Operation Manual

page 15

4 Advanced Features and Options

4.3 Options

4.3.1 PIP Modules

Versatile PIP (Programmable Input Processor)
modules provide flexible expansion features
that can be added to customize the amplifier.
PIP modules plug into the connector inside the
back panel of the amplifier.

PIP modules are available with a features rang­ing from error-driven compressor/limiters to IQ
control. Visit the Crown website at
www.crownaudio.com, or contact Crown Tech­nical Support, for descriptions of available PIP
modules.

4.3.2 IQ-PIP-USP2 Adapter

The IQ-PIP-USP2 Adapter allows the amplifier
to accept the Crown IQ-PIP-USP2 module,
which offers remote control and monitoring via
Crown’s Smart Amp™ IQ features set, plus a
wide range of digital signal processing capabil­ities

Features:

• 24-bit, 48-kHz sampling rate for analog to
digital conversion.

• Programmable DSP filters.

• Greater than one-half second of signal
delay for each channel.

• Input Signal Compressor/Limiter, Ther­mal Limiter and Clip Eliminator for each
channel.

• Presets for easy recall of settings.

• Auto-Standby for reduced energy costs.

• Error reporting.

• Logic input and output.

• Listen Bus allow easy connection to an
audio monitoring system.

4.3.3 Input Sensitivity Switch

The Input Sensitivity Switch is located inside
the PIP compartment at the back of the ampli­fier (Figure 4.1). It is set at the factory to 0.775
volt for rated output into 8 ohms. It can also be
switched to a sensitivity of 1.4 volts, or a fixed
voltage gain of 26 dB (4.8 volts for rated out­put). At 26 dB voltage gain, the equivalent input
sensitivity is:
Macro-Tech 24X6:

2.2V for Channel 2.
Macro-Tech 36X12:

2.6V for Channel 2.
How to change the input sensitivity:

1. Turn off the amplifier and disconnect its
power cord from the AC mains power recep­tacle.

2. Remove the PIP module (two screws).

3. Locate the sensitivity switch access hole
inside the chassis opening as shown in Fig­ure 4.1. It is located just above the phone
jack inputs.

4. Set the switch to the desired position noted
on the access hole label. The position toward
the front panel sets the sensitivity to 1.4

3.1V for Channel 1, and

4.8V for Channel 1, and

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

volts for rated output, the middle position
provides a voltage gain of 26 dB, and the
position toward the back panel sets the sen­sitivity to 0.775 volt for rated output.

5. Replace the PIP module and restore the
power.

4.3.4 Input Ground Lift Switch

The Input Ground Lift switch is located on the
rear panel (Figure 4.1) and can provide isola­tion between the input signal ground and the
AC ground. It affects only the phone jack inputs
and has no effect on the input connectors on
the PIP module. Sliding the switch to the left
isolates or “lifts” the grounds by placing an
impedance between the sleeve of each phone
jack and the circuit ground.

When a PIP module is plugged into the ampli­fier, only the noninverted and inverted signal
lines are connected in parallel with the corre­sponding lines of the input phone jacks. The
signal grounds are not paralleled. For example,
XLR pins 2 and 3 are connected in parallel with
the tip and ring of the corresponding phone
jack. However pin 1 of the XLR is not con­nected in parallel with the sleeve of the phone
jack.

page 16

Figure 4.1 Input Sensitivity and Ground Lift Switches

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

5 Troubleshooting

5.1 Indicators

The front panel has several helpful indicator
LEDs (Figure 5.1).

The amber Enable indicator is provided to
show the amplifier has been turned on (or
enabled) and that its low voltage power supply
and forced-air cooling system are working. It
does not indicate the status of the high voltage
supplies. For example, the Enable indicator will
remain lit during unusual conditions that would
cause the amplifier’s protection systems to put
a high-voltage supply in “standby” mode (see
Section 4.1.3).

The amber ODEP indicators confirm the nor­mal operation of Crown’s patented Output
Device Emulation Protection circuitry. During
normal operation, they glow brightly to show
the presence of reserve thermal-dynamic
energy. They dim proportionally as the energy
reserve decreases. In the rare event that there is
no reserve, the indicators turn off and ODEP
proportionally limits the drive level of the out­put stages so the amplifier can continue safe

operation even when conditions are severe.
(For a more detailed description of ODEP, see
Section 4.1.1).

The ODEP indicator for the affected channel will
turn off if a high-voltage power supply is put in
“standby” mode, a high-voltage power supply
fuse (or breaker) blows, or a transformer acti­vates its thermal protection circuitry (see Sec­tion 4.1.4). Both ODEP indicators turn off if the
amplifier loses AC power, the power switch is
turned off or the low-voltage power supply fuse
blows.

The green Signal/IOC indicators show sig­nal presence, distortion and input overload. As
signal presence indicators, they flash with nor­mal intensity in sync with the output audio sig­nals. As IOC (Input/Output Comparator)
indicators, they flash brightly if there is any dif­ference between the input and output signal
waveforms greater than 0.05%. Because tran­sient distortion happens quickly, a 0.1 second
“hold delay” keeps the indicators on long
enough to be easily noticed. The IOC function
provides proof of distortion-free performance.

As input overload indicators, they flash brightly
with a 0.5 second hold delay to show that an
input signal is too large and must be clipped at
the input.

Under conditions where one of the amplifier’s
high-voltage power supplies is temporarily put
in standby mode, the Signal/IOC indicators will
stay on with full brightness. They will resume
normal operation when the amplifier is no
longer in standby mode.

The table in Figure 5.2 shows the possible
states for the ODEP and Signal/IOC indicators.
It also describes the conditions that may be
associated with the different indicator states.
The Enable indicator will be off with the first
indicator state, “There is no power to the ampli­fier.” All other conditions in the table will occur
with the Enable indicator turned on. It is impor­tant to note the possible states of the indicators
in the rare event that you experience a problem.
This can greatly aid in determining the source
of problems. Please contact your local Crown
representative or our Technical Support Group
for further assistance.

Figure 5.1Indicators

Operation Manual

page 17

5 Troubleshooting

Figure 5.2

ODEP and Signal/IOC

Indicator States

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

page 18

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

6 Theory of Operation

Each channel is powered by its own power
transformer, T100 or T200. Both channels
share TF-1, a low voltage transformer. The sec­ondary outputs of each transformer are full­wave rectified by heavy duty bridge rectifiers
and are filtered by large computer grade capac­itors. A thermal switch embedded in each
transformer protects them from overheating.

The low voltage transformer TF-1 uses a sepa­rate fan motor winding. The TF-1 output is rec­tified by diodes D1-4, generates an unregulated
24 volts. Monolithic regulators U1-2 provide a
regulated ±15 volts.

For simplicity, the following discussion of the
circuitry and operation will refer to one channel
only. Please refer to the block diagram in Figure

6.1
The input signal at the phone jack passes

directly into the balanced gain stage (U104­C,D). Use of a PIP module for input signal
causes the input signal to pass through the PIP
and then to the balanced gain stage.

The balanced gain stage (U104-C,D) causes
balanced to single-ended conversion to take
place using a difference amplifier. From there,
gain can be controlled with a potentiometer.
The error amp (U104-A) amplifies the differ­ence between the output signal and the input
signal from the gain pot, and drives the voltage
translator stage.

The voltage translator stage channels the signal
to the Last Voltage Amplifiers (LVAs), depend­ing on the signal polarity, from the error amp
U104-A. The +LVA (Q105,Q125) and the –LVA
(Q110,Q126), with their push-pull effect
through the bias servo Q318, drive the fully
complementary output stage.

The bias servo Q318 is thermally coupled to
the heat sink, and sets the quiescent bias cur­rent in the output stage to lower the distortion
in the crossover region of the output signal.
D301, D302, D303, and D304 are used to
remove the charge on the unused portion of the
output stage, depending on the polarity of the
output signal.

With the voltage swing provided by the LVAs,
the signal then gains current amplification
through the Darlington emitter-follower output
stage.

The bridge-balanced circuit (U104-B) receives
a signal from the output of the amplifier, and
differences it with the signal at the Vcc supply.
The bridge-balanced circuit then develops a
voltage to drive the bridge-balanced output
stage. This results in the Vcc supply having
exactly one half of the output voltage added to
their quiescent voltage. D309, D310, D311 and
a trimmer resistor set the quiescent current
point for the bridge-balanced output stage.

The protection mechanisms that affect the sig­nal path are implemented to protect the ampli­fier under real-world conditions. These
conditions are high instantaneous current,
excessive temperature, and operation of the
output devices outside safe conditions.

Q107 and Q108 act as a conventional current
limiter, sensing current in the output stage. The
allowable current level is also adjusted as a
function of voltage. When current at any one
instant exceeds the design criteria, the limiters
remove the drive from the LVAs, thus limiting
current in the output stage to a safe level.

To further protect the output stages, a specially
developed ODEP (Output Device Emulation
Protection) circuit is used. It produces an ana­log output proportional to the always changing
safe operating area of the output transistors.
This output controls the translator stage by
removing any drive that exceeds the safe oper­ating area of the output devices. Thermal sen­sor S100 gives the ODEP circuits vital
information on the operating temperature of the
heatsink on which the output devices are
mounted.

Should the amplifier fail in such a way that
would cause DC across the output lead, the DC
protection circuit senses this on the negative
feedback loop and shuts down the power sup­ply until the DC is removed.

Operation Manual

page 19

6 Theory of Operation

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

BALANCED

INPUTS

XLR

1/4" PHONE

P.I.P.

BALANCE

INPUT STAGE

DISPLAY

VARIABLE

GAIN STAGE

ERROR

AMP

TRANSLATOR

E

TRANSLATOR

ODEP

+Vcc

LVA

A
B
C
D

BIAS

LVA

–Vcc

CURRENT

LIMIT

A

(ODEP)

NPN HI

OUTPUT

STAGE

PNP HI

OUTPUT

STAGE

C

(ODEP)

+

ONLY ONE CHANNEL SHOWN

Figure 6.1 Circuit Block Diagram (Channel 1)

OUTPUT

+Vcc

–Vcc

B

(ODEP)

NPN LOW

OUTPUT

STAGE

PNP LOW

OUTPUT

STAGE

D

(ODEP)

BIAS

BRIDGE

BALANCE

+Vcc

–Vcc

page 20

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

7 Specifications

Minimum Guaranteed Power 120VAC, 60 Hz Units

Power in watts per channel,1 kHz, 0.1% THD

Channel 1

2 ohms per ch.
4 ohms per ch.
8 ohms per ch.

Channel 2

2 ohms per ch.
4 ohms per ch.
8 ohms per ch.

Performance (120V AC units in stereo mode with 8 ohm load) Macro-Tech 24X6 Macro-Tech 36X12

Frequency Response

(at 1 watt, 20Hz - 20 kHz) see Figure 7.1.

Phase Response

(at 1 watt, 10Hz - 20 kHz) see Figure 7.4.

Signal to Noise Ratio below full bandwidth power

20 Hz to 20 kHz
A-weighted

Total Harmonic Distortion (THD)

at rated power, from 20 Hz to 1 kHz
at rated power, at 20 kHz

Macro-Tech 24X6 Macro-Tech 36X12

1050W

800W
520W

400W
325W
225W

± 0.1 dB ± 0.1 dB

±10° ±10°

>100 dB
>105 dB

< 0.05%

< 0.1%

1800W
1565W
1120W

675W
480W
310W

>100 dB
>105 dB

< 0.05%
< 0.1%

Macro-Tech 24X6 Macro-Tech 36X12

International Units

875W
745W
510W

375W
335W
230W

1460W
1300W

965W

515W
420W
285W

Intermodulation Distortion (IMD)

60 Hz and 7 kHz at 4:1,from 10 milliwatts to full rated output

Damping Factor

10 Hz to 400 Hz See Figure 7.2.

Crosstalk

(below rated power, 20 Hz to 1 kHz)

Controlled Slew Rate

Channel 1
Channel 2

Input Impedance (nominally balanced, nominally unbalanced) 20 k ohms, 10 k ohms 20 k ohms, 10 k ohms

< 0.05% < 0.05%

>1000 >1000

see Figure 7.5 see Figure 7.5

> 30V per microsecond
> 13V per microsecond

> 30V per microsecond
> 13V per microsecond

Operation Manual

page 21

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

7 Specifications

Performance (continued) Macro-Tech 24X6 Macro-Tech 36X12

Output Impedance See Figure 7.3 See Figure 7.3

Load Impedance (Note: Safe with all types of loads) 2, 4, 8, 16 ohms 2, 4, 8, 16 ohms

Voltage Gain (8-ohm load, rated output at 1 kHz, maximum level setting)

83:1 ±6% or 38 dB ±0.5 dB (Ch. 1, .775V sensitivity)
54:1 ±6% or 35 dB ±0.5 dB (Ch. 2, .775V sensitivity)
20:1 ±6% or 26 dB ±0.5 dB (Ch. 1, 26 dB gain)
20:1 ±6% or 26 dB ±0.5 dB (Ch. 2, 26 dB gain)

Required AC Mains 50/60 Hz; 100-, 120-, and 230 - VAC (±10%) units are avail-

able. 230 VAC, 50/60 Hz units can be used with 220 and 240
VAC. Current, voltage and frequency requirements are pro­vided on the unit’s back panel.

Power Draw at Idle 90 watts or less 90 watts or less

Construction MMMacro-Tech 24X6 MMacro-Tech 36X12

Cooling Internal heat sinks with forced-air cooling

for rapid, uniform heat dissipation

Dimensions

Width
Height
Depth (behind mounting surface)

Weight

Net
Shipping
Center of gravity is 6 inches (15.2 cm) behind the front mounting surface

EIA Standard 19-inch rack mount (EIA RS-310-B)

3.5 inch (8.9 cm)

16 inch (40.6 cm)

45 lb 4 oz (20.5 kg)

54 lb 11 oz (24.8 kg)

124.6:1 ±6% or 42 dB ±0.5 dB (Ch. 1, .775V sensitivity)
64:1 ±6% or 36 dB ±0.5 dB (Ch. 2, .775V sensitivity)
20:1 ±6% or 26 dB ±0.5 dB (Ch. 1, 26 dB gain)
20:1 ±6% or 26 dB ±0.5 dB (Ch. 2, 26 dB gain)

50/60 Hz; 100-, 120-, and 230 - VAC (±10%) units are available. 230
VAC, 50/60 Hz units can be used with 220 and 240 VAC. Current,
voltage and frequency requirements are provided on the unit’s back
panel.

Internal heat sinks with forced-air cooling for

rapid, uniform heat dissipation

EIA Standard 19-inch rack mount (EIA RS-310-B)

3.5 inch (8.9 cm)

16 inch (40.6 cm)

50 lb (22.7 kg)
59 lb (26.8 kg)

page 22

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

(Hz)

7 Specifications

Typical Frequency Response

Figure 7.1

Figure 7.2

Typical Damping Factor

+2

+1

0

–1

–2

dB

–3

–4

–5

–6

–7

10 100 1 K 10 K 100 K

1400

1200

1000

800

600

400

200

100

0

20 100 1 K 10 K 20 K

FREQUENCY (Hz)

FREQUENCY (Hz)

1 watt

8 ohm

8 ohm
4 ohm

2 ohm

Figure 7.4

Typical Phase Response

Figure 7.5

Typical Crosstalk

+45˚

0˚

–45˚

100 1 K 10 K 20 K

FREQUENCY (Hz)

Figure 7.3

Typical Output Impedance

Operation Manual

504.0

126.8

MILLIOHMS

31.8

8.0

2.0

10 100 1 K 10 K 100 K

FREQUENCY

6 dB

page 23

8 AC Power Draw and
Thermal Dissipation

This section provides detailed information about the amount of power
and current drawn from the Macro-Tech 24X6 and 36X12 amplifiers and
the amount of heat produced under various conditions. The calculations
presented here are intended to provide a realistic and reliable depiction
of the amplifiers. The following assumptions or approximations were
made:

• The amplifier’s available channels are loaded, and full power is being
delivered.

• The amplifier efficiency at standard 1 kHz power is estimated to be
65%.

• Quiescent power draw is 90 watts (an almost negligible amount for
full-power calculations).

• Quiescent thermal dissipation equals 105 btu/hr at 90 watts.

• The estimated duty cycles take into account the typical crest factor for
each type of source material.

• Duty cycle of pink noise is 50%.

• Duty cycle of highly compressed rock ‘n’ roll midrange is 40%.

• Duty cycle of rock ‘n’ roll is 30%.

• Duty cycle of background music is 20%.

• Duty cycle of continuous speech is 10%.

• Duty cycle of infrequent, short duration paging is 1%.

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

Here are the equations used to calculate the data presented in Figures

8.1 and 8.2:

The following equation converts power draw in watts to current draw in
amperes:

The value used for Power Factor is 0.65. The Power Factor variable is
needed to compensate for the difference in phase between the AC mains
voltage and current.

The following equation is used to calculate thermal dissipation:

The value used for amplifier inefficiency is 0.35 (1.00-0.65). The factor

3.415 converts watts to btu/hr. Thermal dissipation in btu is divided by
the constant 3.968 to get kcal.

If you plan to measure output power under real-world conditions, the
following equation may also be helpful:

page 24

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

8 AC Power Draw and Thermal Dissipation

Power Draw, Current Draw and Thermal Dissipation at Various Duty Cycles

Power Draw, Current Draw and Thermal Dissipation at Varioius Duty Cycles

Figure 8.1 Macro-Tech 24X6

Figure 8.2 Macro-Tech 36X12

Operation Manual

page 25

9 Service

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

Crown amplifiers are quality units that rarely require
servicing. Before returning your unit for servicing,
please contact Crown Technical Support to verify
the need for servicing.

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.

9.1 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.

9.2 US and Canada 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.

9.2.1 Service at a US or Canada 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
the Crown website at www.crownaudio.com, or by
calling Crown Customer Service.

9.2.2 Factory Service

To obtain factory service, fill out the service infor­mation page found in the back of this manual 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. Contact Crown
Customer Service to obtain prepaid shipping labels
prior to sending the unit. Or, if you prefer, you may
prepay the cost of shipping, and Crown will reim­burse you. Send copies of the shipping receipts to
Crown to receive reimbursement.

Your repaired unit will be returned via UPS ground.
Please contact us if other arrangements are
required.

9.2.3 Factory Service Shipping Instructions:

1. Before sending a Crown product to the factory
for service, first call the Crown Service Depart­ment for a return authorization (RA) number.

2. Be sure to fill out the service information form
that follows and enclose it with your shipment,
either inside the box or in a packing slip enve­lope securely attached to the outside of the
shipping carton. Do not send the service infor­mation form separately. If you are sending the
unit from a Shipping Center, we recommend
taping the form to the product. We also recom­mend recording the serial number and model
before shipping for your reference.

3. To ensure the safe transportation of your unit to
the factory, ship it in an original factory packing
container. If you don’t have the original carton,
you may obtain a product service foam-in­place shipping pack from the Crown Factory
Service Department at the number listed below.
For non-warranty service, you may also pro­vide your own shipping pack, however we still
recommend using a Crown Supplied Shipping

Container. Minimum recommended require­ments for materials are as follows: 275 P.S.I.
burst test Double-Wall carton that allows for 2­inch solid Styrofoam on all six sides of unit or
3 inches of plastic bubble wrap on all six sides
of unit; securely seal the package with an ade­quate carton sealing tape. Do not use light
boxes or “peanuts.” Damage caused by poor
packing cannot be covered under warranty.

4. 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 product documentation, cables and
other hardware.

If you have any questions, please contact Crown
Factory Service.

Crown Factory Service

1718 W. Mishawaka Rd.,

Elkhart, Indiana 46517 U.S.A.

Telephone: [phone]

800-342-6939 (North America,

Puerto Rico, and Virgin Islands only)

Facsimile:

574-294-8301 (Technical Support)

574-294-8124 (Factory Service)

Internet:

http://www.crownaudio.com

page 26

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

YEAR

3

10 Warranty

UNITED STATES & CANADA

SUMMARY OF WARRANTY

Crown International, 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.

WHAT THE WARRANTOR WILL DO

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 inter-

est, 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. Warranty
work for some products can only be performed at
our 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 including the return shipment, and all
taxes, duties, and other customs fees for such for­eign shipments.)

HOW TO OBTAIN WARRANTY
SERVICE

You must notify us of your need for warranty ser­vice within 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.

WARRANTY ALTERATIONS

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.

DESIGN CHANGES

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.

LEGAL REMEDIES OF PURCHASER

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 after expiration of the warranty
period.

THIS STATEMENT OF WARRANTY SUPERSEDES
ANY OTHERS CONTAINED IN THIS MANUAL
FOR CROWN PRODUCTS. 12/01

Operation Manual

page 27

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

YEAR

3

10 Warranty

SUMMARY OF WARRANTY

Crown International, 1718 West Mishawaka Road,
Elkhart, Indiana 46517-4095 U.S.A. warrants to
you, the ORIGINAL PURCHASER and ANY SUB­SEQUENT OWNER of each NEW Crown1 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, and we
further warrant the new Crown product regardless
of the reason for failure, except as excluded in this
Warranty.

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

it for the name “Crown” in this warranty.

ITEMS EXCLUDED FROM THIS CROWN­WARRANTY

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.

WHAT THE WARRANTOR WILL DO

We will remedy any defect, regardless of the rea­son for failure (except as excluded), by repair,

WORLDWIDE EXCEPT USA & CANADA

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.

HOW TO OBTAIN WARRANTY SERVICE

You must notify your local Crown importer of
your need for warranty service within the warranty
period. All components must be shipped in the
original box. 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.

WARRANTY ALTERATIONS

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.

DESIGN CHANGES

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.

LEGAL REMEDIES OF PURCHASER

No action to enforce this Crown Warranty shall be
commenced after expiration of the warranty
period.

THIS STATEMENT OF WARRANTY SUPERSEDES
ANY OTHERS CONTAINED IN THIS MANUAL FOR
CROWN PRODUCTS. 7/01

page 28

Operation Manual

Macro-Tech MA-24X6 & 36X12 Power Amplifiers

Crown Factory Service Information

Shipping Address: Crown Factory Service, 1718 W. Mishawaka Rd., Elkhart, IN 46517

Phone: [phone] or 1-574-294-8200 Fax: [phone]

Owner’s Name : ________________________________________________________________________________________________________________________________________________________________

Shipping Address: ______________________________________________________________________________________________________________________________________________________________

Phone Number: ________________________________Fax Number: ________________________________ Email ________________________________________________________________________________

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.)

______________________________________________________________________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________________

Other equipment in system: ___________________________________________________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________________

If warranty has expired, payment will be: ! Cash/Check ! Visa ! Master Card ! C.O.D. ! Purchase Order for Crown Dealer

Card Number:___________________________________ Exp. Date:___________________

Signature:______________________________________________________________________

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

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Macro-Tech MA-24X6 & 36X12 Power Amplifiers

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Operation Manual