Crown Audio Stereo Amplifier MA 36X12 User Manual

Macro-Tech Series  
MA-24X6  
Operation Manual  
MA-36X12  
Obtaining Other Language Versions: To obtain information in another language about the use of this product, please contact your  
local Crown Distributor. If you need assistance locating your local distributor, please contact Crown at 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  
Trademark Notice: SmartAmp, Grounded Bridge and PIP are trademarks and Amcron, Crown, Macro-Tech, IOC, ODEP, IQ, IQ Sys-  
tem, and P.I.P. are registered trademarks of Crown International. Other trademarks are the property of their respective owners.  
Some models may be exported under the name Amcron.®  
©2003 by Crown Audio, Inc. P.O. Box 1000, Elkhart, Indiana 46515-1000 U.S.A. Telephone: 574-294-8000  
125782-5  
6/03  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
Crown International, Inc.  
TCF Technical Certificate No: P4300CRI1.IWS  
DECLARATION of CONFORMITY  
Technical Construction File Route  
Sue Whitfield  
Issued By: Crown International, Inc.  
1718 W. Mishawaka Road  
574-294-8289  
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  
European Representative's Name and Address:  
Nick Owen  
19 Clos Nant Coslech  
Pontprennau  
Cardiff  
Equipment Type: Commercial Audio Power Amplifiers  
Family Name: Macro-Tech  
CF23 8ND United Kingdom  
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  
Date of Issue: March 28, 2000  
Title: Senior Vice President of Manufacturing  
Operation Manual  
page 3  
DUE TO LINE CURRENT HARMONICS, WE RECOMMEND THAT YOU CONTACT YOUR SUPPLY AUTHORITY BEFORE CONNECTION.  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
Table of Contents  
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  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
1 Welcome  
Congratulations on your purchase of a Macro-  
Tech ® 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.  
1.1 Features  
1.2 How to Use This Manual  
Full protection against shorted outputs,  
open circuits, DC, mismatched loads, gen-  
eral overheating, high frequency overloads  
and internal faults.  
Crown’s Grounded Bridge™ design deliv-  
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 addi-  
tional information, please consult Crown’s  
Amplifier Application Guide (available online at  
your system installer or retailer.  
ers incredible voltage swings without  
using stressful output transistor configura-  
tions like conventional amplifiers. The  
results are lower distortion and superior  
reliability.  
Extra rugged, extruded aluminum front  
panel with ODEP and Signal Presence/IOC  
indicators for each channel, as well as an  
Enable indicator.  
Patented ODEP (Output Device Emulation  
Protection) circuitry compensates for  
overheating and overload to keep the  
amplifier working long after others would  
fail.  
IOC ® (Input/Output Comparator) circuitry  
immediately alerts of any distortion  
exceeding 0.05%, providing dynamic  
proof of distortion-free performance.  
Macro-Tech 36x12: Articulated VZ power  
supply for Channel 1 (3600) provides the  
best power matching to your load.  
We strongly recommend you read all instruc-  
tions, 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.  
Efficient heat sinks and forced air cooling  
prevent overheating and prolong compo-  
nent life.  
Because it’s a Macro-Tech, you have the added  
benefit of PIP ™ compatibility for access to  
custom input modules and ODEP ® protection  
to keep the show going long after other amplifi-  
ers would fail.  
Balanced inputs with three-position sensi-  
tivity switch and adjustable front panel  
level controls.  
PIP connector accepts accessories that tai-  
lor the amplifier to suit specific applica-  
tions.  
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.  
5-way binding post outputs provide versa-  
tile connection.  
Very low harmonic and intermodulation  
distortion give the best dynamic transfer  
function in the industry.  
Mounts in a standard 19-inch (48.3-cm)  
equipment rack (units can also be  
stacked).  
High damping factor provides superior  
control over low frequency drivers for a  
clean, accurate low end.  
In addition, MA-24X6 and MA-36X12 amplifi-  
ers include a number of features which require  
some explanation before they can be used to  
their maximum advantage.  
Three Year “No-Fault” Full Warranty com-  
pletely protects your investment and guar-  
antees its specifications.  
Please take the time to study this manual so  
that you can obtain the best possible service  
from your amplifier.  
Operation Manual  
page 5  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
2 Setup  
2.3 Ensure Proper Cooling  
2.2 Install Your Amplifier  
2.1 Unpack Your Amplifier  
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.  
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 (counterclock-  
wise).  
Please unpack and inspect your amplifier for  
any damage that may have occurred during  
transit. If damage is found, notify the transpor-  
tation company immediately. Only you can  
initiate a claim for shipping damage. Crown  
will be happy to help as needed. Save the ship-  
ping carton as evidence of damage for the ship-  
per’s inspection.  
Use a standard 19-inch (48.3 cm) equipment  
rack. See Figure 2.1 for amplifier dimensions.  
Figure 2.2 illustrates standard amplifier airflow.  
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):  
You may also stack amps without using a cabi-  
net.  
NOTE: When transporting, amplifiers should be  
supported at both front and back.  
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 Instruc-  
tions found at the beginning of this  
manual.  
3.5 in  
8.9 cm  
19 in  
48.3 cm  
Figure 2.2 Airflow  
SIDE VIEW  
16 in  
40.6 cm  
2.5 in  
6.35 cm  
Figure 2.1 Dimensions  
page 6  
Operation Manual  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
2 Setup  
2.4 Choose Input Wire  
and Connectors  
Unbalanced Line  
Balanced Line  
Figure 2.3 shows connector pin assignments for  
balanced wiring, and Figure 2.4 shows connec-  
tor pin assignments for unbalanced wiring.  
NOTE: Custom wiring should only be  
performed by qualified personnel.  
Figure 2.3 Balanced Input  
Connector Wiring  
Figure 2.4 Unbalanced Input  
Connector Wiring  
Operation Manual  
page 7  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
2 Setup  
2.5 Choose Output Wire and Con-  
nectors  
OUTPUTS  
CH-1  
CH-2  
Crown recommends using pre-built or profes-  
sionally 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 posi-  
tions for these connectors should there-  
fore be used on European models.  
Figure 2.5 Output Connector Wiring  
Using the guidelines below, select the appropri-  
ate size of wire based on the distance from  
amplifier to speaker.  
Distance  
up to 25 ft.  
26-40 ft.  
Wire Size  
16 AWG  
14 AWG  
12 AWG  
10 AWG  
8 AWG  
41-60 ft.  
61-100 ft.  
101-150 ft.  
151-250 ft.  
6 AWG  
CAUTION: Never use shielded cable for  
output wiring.  
page 8  
Operation Manual  
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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 medium-  
power 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 chan-  
nel. Note: Because of its higher output power,  
Channel 1 of a Macro-Tech 36x12 has an addi-  
tional 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  
Figure 2.6 System Wiring (a Macro-Tech 36x12 is shown)  
Operation Manual  
page 9  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
2 Setup  
2.7 Connect to AC Mains  
2.8 Startup Procedure  
Connect the AC power cordset of your amplifier  
to the AC mains power source (power outlet).  
Use the following procedure when first turning  
on your amplifier:  
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.  
1. Turn down the level of your audio source.  
2. Turn down the level controls of the ampli-  
fier.  
3. Turn on the “Enable” switch. The Enable  
indicator should glow.  
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.  
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  
page 10  
Operation Manual  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
3 Operation  
3.1 Precautions  
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.  
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:  
4. Never connect the output to a power  
supply, battery or power main. Elec-  
trical shock may result.  
1. Before use, your amplifier first must be con-  
figured for proper operation, including input  
and output wiring hookup. Improper wiring  
can result in serious operating difficulties.  
For information on wiring and configura-  
tion, please consult the Setup section of this  
manual or, for advanced setup techniques,  
consult Crown’s Amplifier Application  
dio.com.  
5. Tampering with the circuitry, or making  
unauthorized circuit changes, may be haz-  
ardous and invalidates all agency listings.  
6. Do not operate the amplifier with the Signal/  
IOC LEDs constantly indicating an IOC con-  
dition.  
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.  
2. Use care when making connections, select-  
ing signal sources and controlling the out-  
put level. The load you save may be your  
own!  
Operation Manual  
page 11  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
3 Operation  
namic energy. They dim proportionally as  
energy reserves decrease. In the event that  
energy reserves are depleted, the indica-  
tors turn off and ODEP limiting occurs.  
See Section 4.1 for more about ODEP.  
C. Signal/IOC Indicator  
3.2 Front Panel Controls  
and Indicators  
Green LED, one per channel. Dual-pur-  
pose 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.  
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.  
E. Enable Indicator  
Green LED indicates amplifier has been  
turned on and AC power is available.  
B. Level Control  
F. Enable Switch  
Rotary detented level control, one per  
channel.  
D. ODEP Indicator  
Amplifier is on when the switch is in the IN  
position.  
Red LED, one per channel, illuminates  
brightly to indicate presence of thermody-  
Figure 3.1 Front Panel  
Controls and Indicators  
page 12  
Operation Manual  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
3 Operation  
used in place of the P.I.P.-FX. They add addi-  
balanced (tip, ring and sleeve) or unbalanced  
(tip and sleeve) input signals. Because they are  
electrically in parallel with the PIP input con-  
nectors, input signals should not be connected  
to the phone jacks when certain PIP modules  
are installed (see the Crown Amplifier Applica-  
dio.com). The phone jacks can also be used as  
“daisy chain” outputs to simplify connecting  
input signals to multiple amplifiers.  
3.3 Back Panel Controls  
and Connectors  
L. Balanced XLR Inputs  
tional features that customize the amplifier for  
different applications. For information on avail-  
able PIP modules visit the Crown website at  
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 .  
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.  
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).  
H. Reset Switches  
The reset switches are used to reset the break-  
ers that safeguard each power supply from  
overload.  
M. Output Jacks  
K. Ground Lift Switch  
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.  
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.  
I. PIP Module  
J. Balanced Phone Jack Inputs  
The standard P.I.P.-FX is included with your  
amplifier. It provides female XLR input connec-  
tors. A variety of other PIP modules can be  
Balanced ¼-inch phone jack input connectors  
are provided on the back panel of your ampli-  
fier. The phone jacks can be wired for either  
Figure 3.2 Back Panel  
Controls and Connectors  
Operation Manual  
page 13  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
4 Advanced Features  
and Options  
high-voltage supplies to protect the amplifier  
and connected loads. The standby mode can be  
identified using the indicator table in Figure  
5.2.  
This level of protection enables Crown to  
increase output transistor utilization while  
greatly increasing amplifier reliability.  
NOTE: For detailed information about  
these Crown amplifier features, please  
consult the Crown Amplifier Application  
Guide, available on the Crown website  
Finally, this onboard intelligence is monitored  
in two ways. First, the front panel ODEP indica-  
tors 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.  
Standby mode can be activated in several situa-  
tions. First, if dangerous subsonic frequencies  
or direct current (DC) is detected in the ampli-  
fier’s output, the unit will activate its DC/low-  
frequency 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 fre-  
quency or DC output. Although it is extremely  
unlikely that you will ever activate the ampli-  
fier’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.  
4.1 Protection Systems  
Your Crown amplifier provides extensive pro-  
tection and diagnostic capabilities, including  
ODEP, IOC., “standby” mode, fuses (or break-  
ers), and special thermal protection for the  
unit’s transformers.  
With ODEP you get the maximum power with  
the maximum protection—the show goes on!  
4.1.1 Output Device Emulation  
Protection (ODEP)  
4.1.2 IOC (Input Output Compara-  
tor)  
Crown invented ODEP to solve two long stand-  
ing problems in amplifier design: To prevent  
amplifier shutdown during demanding opera-  
tion and to increase the efficiency of output cir-  
cuitry.  
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 consid-  
ered 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.  
To do this, Crown established a rigorous pro-  
gram 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 operat-  
ing conditions of those output transistors. Its  
name describes what it does: Output Device  
Emulation Protection or ODEP. It not only simu-  
lates 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 condi-  
tions, ODEP immediately limits the drive level  
until it falls within the SOA. Limiting is propor-  
tional and kept to an absolute minimum—only  
what is required to prevent the possibility of  
output transistor damage.  
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 ampli-  
fier 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.  
IOC is designed to report any form of distor-  
tion. IOC not only checks the waveform for dis-  
tortion, 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 opera-  
tional and undistorted. IOC provides an on-line  
proof of performance.  
The amplifier’s transformer thermal protection  
circuitry is activated in very unusual circum-  
stances where the unit’s transformer tempera-  
ture 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 oper-  
ation after the transformer cools to a safe tem-  
perature. (For more information on transformer  
thermal protection, refer to the following sec-  
tion.)  
4.1.3 Standby Mode  
At the heart of the protection systems is the  
standby mode which removes power from the  
page 14  
Operation Manual  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
4 Advanced Features  
and Options  
4.1.4 Transformer Thermal  
Protection  
when the amplifier is used to drive a 1-ohm  
load in Stereo mode, or when a signal over-  
loads the input and is clipped severely.  
Crown's Grounded Bridge design delivers large  
voltage swings without stressing output tran-  
sistors. The results are higher efficiency, lower  
distortion and superior reliablility.  
All Macro-Tech amplifiers have transformer  
thermal protection. It protects the power sup-  
plies 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 exces-  
sive heat. The switch automatically resets when  
the transformer cools to a safe temperature.  
Macro-Tech amplifiers do not trip their break-  
ers 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.  
4.2.2 Variable Impedance (VZ)  
(Macro-Tech 36X12 only)  
VZ is the name of Crown's patented articulated  
power supply technology. This innovative tech-  
nology permits us to pack large amounts of  
power into a compact package while achieving  
ultra-low distortion and without generating  
excessive heat.  
4.2 Circuit Designs  
It is very unlikely that you will ever see a  
Macro-Tech amplifier activate transformer ther-  
mal protection as long as it is operated within  
rated conditions (see Section 7, Specifica-  
tions). One reason is that ODEP keeps the  
amplifier working under very severe conditions.  
Even so, higher than rated output levels, exces-  
sively 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.  
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 volt-  
age generated by the power supplies.  
An amplifier power supply must be large  
enough to handle both the maximum voltage  
and maximum current necesary for the ampli-  
fier 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 dynami-  
cally adapting to both signal and load require-  
ments in real-time. This provides the best  
power match to the widest range of loads.  
The power supply bridge rectifier is not ground  
referenced, and the transformer secondary is  
not center-tapped. This allows the power sup-  
ply 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.  
Macro-Tech amplifiers are designed to keep  
working under conditions where other amplifi-  
ers would fail. But even when its limits are  
exceeded, it will still protect itself—and your  
investment—from damage.  
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 seg-  
ments are arranged in parallel to deliver twice  
the current of a single segment. Sensing cir-  
cuitry "watches" the voltage of the signal to  
determine when to switch VZ modes. The  
switching circuitry is designed to prevent audi-  
ble switching distortion to yield the highest  
possible dynamic transfer function—you hear  
only the music and not the amplifier.  
Composite output devices are arranged to func-  
tion as gigantic NPN and PNP devices. Each  
output stage has two composite NPN and two  
composite PNP devices. The devices con-  
nected 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.  
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 out-  
put levels result in current draw that exceeds  
their rating. Again, this should only be possible  
when operating outside rated conditions, like  
With VZ, you get not only maximum power and  
safety, but you also get the best power match-  
ing to your load.  
Operation Manual  
page 15  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
4 Advanced Features  
and Options  
4.3 Options  
4.3.3 Input Sensitivity Switch  
volts for rated output, the middle position  
provides a voltage gain of 26 dB, and the  
position toward the back panel sets the sen-  
sitivity to 0.775 volt for rated output.  
The Input Sensitivity Switch is located inside  
the PIP compartment at the back of the ampli-  
fier (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 out-  
put). At 26 dB voltage gain, the equivalent input  
sensitivity is:  
Macro-Tech 24X6: 3.1V for Channel 1, and  
2.2V for Channel 2.  
Macro-Tech 36X12: 4.8V for Channel 1, and  
2.6V for Channel 2.  
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.  
5. Replace the PIP module and restore the  
power.  
4.3.4 Input Ground Lift Switch  
PIP modules are available with a features rang-  
ing from error-driven compressor/limiters to IQ  
control. Visit the Crown website at  
nical Support, for descriptions of available PIP  
modules.  
The Input Ground Lift switch is located on the  
rear panel (Figure 4.1) and can provide isola-  
tion 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.  
How to change the input sensitivity:  
4.3.2 IQ-PIP-USP2 Adapter  
1. Turn off the amplifier and disconnect its  
power cord from the AC mains power recep-  
tacle.  
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 capabil-  
ities  
When a PIP module is plugged into the ampli-  
fier, only the noninverted and inverted signal  
lines are connected in parallel with the corre-  
sponding 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 con-  
nected in parallel with the sleeve of the phone  
jack.  
2. Remove the PIP module (two screws).  
3. Locate the sensitivity switch access hole  
inside the chassis opening as shown in Fig-  
ure 4.1. It is located just above the phone  
jack inputs.  
Features:  
24-bit, 48-kHz sampling rate for analog to  
digital conversion.  
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  
Programmable DSP filters.  
Greater than one-half second of signal  
delay for each channel.  
Input Signal Compressor/Limiter, Ther-  
mal 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.  
Figure 4.1 Input Sensitivity and Ground Lift Switches  
page 16  
Operation Manual  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
5 Troubleshooting  
operation even when conditions are severe.  
(For a more detailed description of ODEP, see  
Section 4.1.1).  
5.1 Indicators  
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.  
The front panel has several helpful indicator  
LEDs (Figure 5.1).  
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 acti-  
vates its thermal protection circuitry (see Sec-  
tion 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 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).  
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 ampli-  
fier.” All other conditions in the table will occur  
with the Enable indicator turned on. It is impor-  
tant 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.  
The green Signal/IOC indicators show sig-  
nal presence, distortion and input overload. As  
signal presence indicators, they flash with nor-  
mal intensity in sync with the output audio sig-  
nals. As IOC (Input/Output Comparator)  
indicators, they flash brightly if there is any dif-  
ference between the input and output signal  
waveforms greater than 0.05%. Because tran-  
sient 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.  
The amber ODEP indicators confirm the nor-  
mal 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 out-  
put stages so the amplifier can continue safe  
Figure 5.1Indicators  
Operation Manual  
page 17  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
5 Troubleshooting  
Figure 5.2  
ODEP and Signal/IOC  
Indicator States  
page 18  
Operation Manual  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
6 Theory of Operation  
Each channel is powered by its own power  
The voltage translator stage channels the signal  
to the Last Voltage Amplifiers (LVAs), depend-  
ing 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 protection mechanisms that affect the sig-  
nal path are implemented to protect the ampli-  
fier under real-world conditions. These  
conditions are high instantaneous current,  
excessive temperature, and operation of the  
output devices outside safe conditions.  
transformer, T100 or T200. Both channels  
share TF-1, a low voltage transformer. The sec-  
ondary outputs of each transformer are full-  
wave rectified by heavy duty bridge rectifiers  
and are filtered by large computer grade capac-  
itors. A thermal switch embedded in each  
transformer protects them from overheating.  
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.  
The bias servo Q318 is thermally coupled to  
the heat sink, and sets the quiescent bias cur-  
rent 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.  
The low voltage transformer TF-1 uses a sepa-  
rate fan motor winding. The TF-1 output is rec-  
tified 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  
To further protect the output stages, a specially  
developed ODEP (Output Device Emulation  
Protection) circuit is used. It produces an ana-  
log 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 oper-  
ating area of the output devices. Thermal sen-  
sor S100 gives the ODEP circuits vital  
information on the operating temperature of the  
heatsink on which the output devices are  
mounted.  
With the voltage swing provided by the LVAs,  
the signal then gains current amplification  
through the Darlington emitter-follower output  
stage.  
The input signal at the phone jack passes  
directly into the balanced gain stage (U104-  
C,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 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 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 differ-  
ence between the output signal and the input  
signal from the gain pot, and drives the voltage  
translator stage.  
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 sup-  
ply until the DC is removed.  
Operation Manual  
page 19  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
6 Theory of Operation  
+Vcc  
+Vcc  
LVA  
A
B
(ODEP)  
(ODEP)  
TRANSLATOR  
NPN HI  
OUTPUT  
STAGE  
NPN LOW  
OUTPUT  
STAGE  
+Vcc  
E
A
B
C
D
OUTPUT  
XLR  
CURRENT  
LIMIT  
ODEP  
BIAS  
BIAS  
P.I.P.  
+
BALANCED  
INPUTS  
BALANCE  
VARIABLE  
GAIN STAGE  
ERROR  
AMP  
BRIDGE  
BALANCE  
–Vcc  
INPUT STAGE  
1/4" PHONE  
PNP HI  
OUTPUT  
STAGE  
PNP LOW  
OUTPUT  
STAGE  
TRANSLATOR  
LVA  
–Vcc  
C
D
DISPLAY  
(ODEP)  
(ODEP)  
–Vcc  
ONLY ONE CHANNEL SHOWN  
Figure 6.1 Circuit Block Diagram (Channel 1)  
page 20  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
7 Specifications  
Minimum Guaranteed Power  
International Units  
Macro-Tech 24X6  
Macro-Tech 36X12  
Macro-Tech 24X6  
Macro-Tech 36X12  
Power in watts per channel,1 kHz, 0.1% THD  
Channel 1  
1050W  
800W  
520W  
1800W  
1565W  
1120W  
875W  
745W  
510W  
1460W  
1300W  
965W  
2 ohms per ch.  
4 ohms per ch.  
8 ohms per ch.  
Channel 2  
400W  
325W  
225W  
675W  
480W  
310W  
375W  
335W  
230W  
515W  
420W  
285W  
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  
0.1 dB  
0.1 dB  
(at 1 watt, 20Hz - 20 kHz) see Figure 7.1.  
Phase Response  
10°  
10°  
(at 1 watt, 10Hz - 20 kHz) see Figure 7.4.  
Signal to Noise Ratio below full bandwidth power  
>100 dB  
>105 dB  
>100 dB  
>105 dB  
20 Hz to 20 kHz  
A-weighted  
Total Harmonic Distortion (THD)  
< 0.05%  
< 0.1%  
< 0.05%  
< 0.1%  
at rated power, from 20 Hz to 1 kHz  
at rated power, at 20 kHz  
Intermodulation Distortion (IMD)  
< 0.05%  
>1000  
< 0.05%  
>1000  
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  
see Figure 7.5  
see Figure 7.5  
(below rated power, 20 Hz to 1 kHz)  
Controlled Slew Rate  
Channel 1  
> 30V per microsecond  
> 13V per microsecond  
> 30V per microsecond  
> 13V per microsecond  
Channel 2  
Input Impedance (nominally balanced, nominally unbalanced)  
20 k ohms, 10 k ohms  
20 k ohms, 10 k ohms  
Operation Manual  
page 21  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
7 Specifications  
Performance (continued)  
Macro-Tech 24X6  
See Figure 7.3  
Macro-Tech 36X12  
See Figure 7.3  
Output Impedance  
Load Impedance (Note: Safe with all types of loads)  
Voltage Gain (8-ohm load, rated output at 1 kHz, maximum level setting)  
2, 4, 8, 16 ohms  
2, 4, 8, 16 ohms  
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)  
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)  
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 pro-  
vided on the unit’s back panel.  
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.  
Power Draw at Idle  
Construction  
Cooling  
90 watts or less  
90 watts or less  
MMMacro-Tech 24X6  
MMacro-Tech 36X12  
Internal heat sinks with forced-air cooling  
for rapid, uniform heat dissipation  
Internal heat sinks with forced-air cooling for  
rapid, uniform heat dissipation  
Dimensions  
EIA Standard 19-inch rack mount (EIA RS-310-B)  
3.5 inch (8.9 cm)  
EIA Standard 19-inch rack mount (EIA RS-310-B)  
3.5 inch (8.9 cm)  
Width  
Height  
16 inch (40.6 cm)  
16 inch (40.6 cm)  
Depth (behind mounting surface)  
Weight  
Net  
Shipping  
50 lb (22.7 kg)  
59 lb (26.8 kg)  
45 lb 4 oz (20.5 kg)  
54 lb 11 oz (24.8 kg)  
Center of gravity is 6 inches (15.2 cm) behind the front mounting surface  
page 22  
Operation Manual  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
7 Specifications  
+2  
Figure 7.1  
Typical Frequency Response  
Figure 7.4  
+1  
Typical Phase Response  
0
–1  
8 ohm  
4 ohm  
1 watt  
–2  
dB  
2 ohm  
–3  
+45˚  
0˚  
–4  
–5  
–6  
–7  
10  
100  
1 K  
10 K  
100 K  
–45˚  
FREQUENCY (Hz)  
1400  
Figure 7.2  
Typical Damping Factor  
100  
1 K  
10 K  
20 K  
1200  
FREQUENCY (Hz)  
1000  
800  
600  
400  
200  
100  
0
8 ohm  
Figure 7.5  
Typical Crosstalk  
20  
100  
1 K  
FREQUENCY (Hz)  
10 K  
20 K  
Figure 7.3  
Typical Output Impedance  
504.0  
126.8  
MILLIOHMS  
6 dB  
31.8  
8.0  
2.0  
10  
100  
1 K  
10 K  
100 K  
FREQUENCY (Hz)  
Operation Manual  
page 23  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
8 AC Power Draw and  
Thermal Dissipation  
This section provides detailed information about the amount of power  
Here are the equations used to calculate the data presented in Figures  
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:  
8.1 and 8.2:  
• The amplifier’s available channels are loaded, and full power is being  
delivered.  
The following equation converts power draw in watts to current draw in  
amperes:  
• 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 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 estimated duty cycles take into account the typical crest factor for  
each type of source material.  
• Duty cycle of pink noise is 50%.  
The following equation is used to calculate thermal dissipation:  
• 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%.  
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  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
8 AC Power Draw and  
Thermal Dissipation  
Figure 8.1 Macro-Tech 24X6  
Power Draw, Current Draw and Thermal Dissipation at Various Duty Cycles  
Figure 8.2 Macro-Tech 36X12  
Power Draw, Current Draw and Thermal Dissipation at Varioius Duty Cycles  
Operation Manual  
page 25  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
9 Service  
9.2.2 Factory Service  
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.  
Container. Minimum recommended require-  
ments for materials are as follows: 275 P.S.I.  
burst test Double-Wall carton that allows for 2-  
inch 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 ade-  
quate carton sealing tape. Do not use light  
To obtain factory service, fill out the service infor-  
mation 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.  
This unit has very sophisticated circuitry which  
should only be serviced by a fully trained techni-  
cian. This is one reason why each unit bears the fol-  
lowing label:  
For warranty service, we will pay for ground ship-  
ping 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 reim-  
burse you. Send copies of the shipping receipts to  
Crown to receive reimbursement.  
boxes or “peanuts.” Damage caused by poor  
packing cannot be covered under warranty.  
CAUTION: To prevent electric shock, do not  
remove covers. No user serviceable parts  
inside. Refer servicing to a qualified techni-  
cian.  
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.  
Your repaired unit will be returned via UPS ground.  
Please contact us if other arrangements are  
required.  
9.1 Worldwide Service  
Service may be obtained from an authorized service  
center. (Contact your local Crown/Amcron repre-  
sentative 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.  
If you have any questions, please contact Crown  
Factory Service.  
9.2.3 Factory Service Shipping  
Instructions:  
Crown Factory Service  
1718 W. Mishawaka Rd.,  
Elkhart, Indiana 46517 U.S.A.  
1. Before sending a Crown product to the factory  
for service, first call the Crown Service Depart-  
ment for a return authorization (RA) number.  
Telephone: 574-294-8200  
800-342-6939 (North America,  
Puerto Rico, and Virgin Islands only)  
Remember to transport your unit in the original fac-  
tory pack.  
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 enve-  
lope securely attached to the outside of the  
shipping carton. Do not send the service infor-  
mation form separately. If you are sending the  
unit from a Shipping Center, we recommend  
taping the form to the product. We also recom-  
mend recording the serial number and model  
before shipping for your reference.  
9.2 US and Canada Service  
Facsimile:  
574-294-8301 (Technical Support)  
574-294-8124 (Factory 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.  
Internet:  
9.2.1 Service at a US or Canada Ser-  
vice Center  
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-in-  
place shipping pack from the Crown Factory  
Service Department at the number listed below.  
For non-warranty service, you may also pro-  
vide your own shipping pack, however we still  
recommend using a Crown Supplied Shipping  
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  
calling Crown Customer Service.  
page 26  
Operation Manual  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
10 Warranty  
UNITED STATES & CANADA  
SUMMARY OF WARRANTY  
est, insurance, closing costs, and other finance  
charges less a reasonable depreciation on the  
product from the date of original purchase. War-  
ranty work can only be performed at our autho-  
rized 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 defec-  
tive 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 for-  
eign country and the port of entry in the United  
States including the return shipment, and all  
taxes, duties, and other customs fees for such for-  
eign shipments.)  
FROM ANY DEFECT IN THE NEW CROWN  
PRODUCT. THIS INCLUDES ANY DAMAGE TO  
ANOTHER PRODUCT OR PRODUCTS RESULT-  
ING FROM SUCH A DEFECT. SOME STATES DO  
NOT ALLOW THE EXCLUSION OR LIMITATIONS  
OF INCIDENTAL OR CONSEQUENTIAL DAM-  
AGES, SO THE ABOVE LIMITATION OR EXCLU-  
SION MAY NOT APPLY TO YOU.  
Crown International, 1718 West Mishawaka Road,  
Elkhart, Indiana 46517-4095 U.S.A. warrants to  
you, the ORIGINAL PURCHASER and ANY SUB-  
SEQUENT 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 War-  
ranty.  
WARRANTY ALTERATIONS  
No person has the authority to enlarge, amend, or  
modify this Crown Warranty. This Crown War-  
ranty 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.  
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 inten-  
tional 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.  
HOW TO OBTAIN WARRANTY  
SERVICE  
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.  
You must notify us of your need for warranty ser-  
vice 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 reason-  
able 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 autho-  
rized service center immediately.  
LEGAL REMEDIES OF PURCHASER  
WHAT THE WARRANTOR WILL DO  
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.  
We will remedy any defect, regardless of the rea-  
son for failure (except as excluded), by repair,  
replacement, or refund. We may not elect refund  
unless you agree, or unless we are unable to pro-  
vide 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-  
DISCLAIMER OF CONSEQUENTIAL  
AND INCIDENTAL DAMAGES  
THIS STATEMENT OF WARRANTY SUPERSEDES  
ANY OTHERS CONTAINED IN THIS MANUAL  
YOU ARE NOT ENTITLED TO RECOVER FROM  
US ANY INCIDENTAL DAMAGES RESULTING  
FOR CROWN PRODUCTS.  
12/01  
Operation Manual  
page 27  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
10 Warranty  
WORLDWIDE EXCEPT USA & CANADA  
SUMMARY OF WARRANTY  
replacement, or refund. We may not elect refund  
unless you agree, or unless we are unable to pro-  
vide 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. War-  
ranty work can only be performed at our autho-  
rized service centers. We will remedy the defect  
and ship the product from the service center  
within a reasonable time after receipt of the defec-  
tive product at our authorized service center.  
DISCLAIMER OF CONSEQUENTIAL AND  
INCIDENTAL DAMAGES  
Crown International, 1718 West Mishawaka Road,  
Elkhart, Indiana 46517-4095 U.S.A. warrants to  
you, the ORIGINAL PURCHASER and ANY SUB-  
SEQUENT OWNER of each NEW Crown1 product,  
for a period of three (3) years from the date of pur-  
chase 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.  
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.  
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 inten-  
tional 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.  
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 cen-  
ter are not satisfactory, notify our authorized ser-  
vice center immediately.  
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.  
WHAT THE WARRANTOR WILL DO  
We will remedy any defect, regardless of the rea-  
son for failure (except as excluded), by repair,  
THIS STATEMENT OF WARRANTY SUPERSEDES  
ANY OTHERS CONTAINED IN THIS MANUAL FOR  
CROWN PRODUCTS.  
7/01  
page 28  
Operation Manual  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
Crown Factory Service Information  
Shipping Address: Crown Factory Service, 1718 W. Mishawaka Rd., Elkhart, IN 46517  
Phone: 1-800-342-6939 or 1-574-294-8200 Fax: 1-574-294-8124  
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.  
Operation Manual  
page 29  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
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page 30  
Operation Manual  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
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Operation Manual  
page 31  
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Macro-Tech MA-24X6 & 36X12 Power Amplifiers  
page 32  
Operation Manual  
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