Crown Macro-Tech 3600 VZ User manual

Model:
Macro-Tech 3600VZ
Some models may be exported under the name Amcron .
®
125113-3
4/00
©2000 by Crown International, Inc., P.O. Box 1000, Elkhart, IN 46515-1000 U.S.A. Telephone: 219-294-
8000. Fax: [phone]. Macro-Tech amplifiers are produced by the Professional Audio Division of Crown
International,Inc.Trademark Notice: SmartAmp,
™
PIP,
™and
Grounded Bridge
™are trademarks and
Amcron ,
®
Crown ,
®
Macro-Tech ,
®
IOC ,
®
ODEP ,
®
IQ System ,
® and
P.I.P.
®are registered trademarks of Crown
International, Inc. Other trademarks are the property of their respective owners.

WORLDWIDE
SUMMARY OF WARRANTY
The Crown Audio Division of Crown International, Inc., 1718 West
Mishawaka Road, Elkhart, Indiana 46517-4095 U.S.A. warrants to you, the
ORIGINAL PURCHASER and ANY SUBSEQUENT OWNER of each
NEW Crown1product, 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 Crown Warranty.
1
Note: If your unit bears the name “Amcron,” please substitute it for the
name “Crown” in this warranty.
ITEMS EXCLUDED FROM THIS CROWN WARRANTY
This Crown Warranty is in effect only for failure of a new Crown product
which occurred within the Warranty Period. It does not cover any product
which has been damaged because of any intentional misuse, accident,
negligence, or loss which is covered under any of your insurance contracts.
This Crown Warranty also does not extend to the new Crown product if the
serial number has been defaced, altered, or removed.
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 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 us of your need for warranty service not later than ninety
(90) days after expiration of the warranty period. All components must be
shipped in a factory pack. Corrective action will be taken within a
reasonable time of the date of receipt of the defective product by our
authorized service center. If the repairs made by our authorized service
center are not satisfactory, notify our authorized service center
immediately.
DISCLAIMER OF CONSEQUENTIAL AND INCIDENTAL DAMAGES
YOU ARE NOT ENTITLED TO RECOVER FROM US ANY INCIDENTAL
DAMAGES RESULTING FROM ANY DEFECT IN THE NEW CROWN
PRODUCT. THIS INCLUDES ANY DAMAGE TO ANOTHER PRODUCT
OR PRODUCTS RESULTING FROM SUCH A DEFECT.
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 later than
ninety (90) days after expiration of the warranty period.
THIS STATEMENT OF WARRANTY SUPERSEDES ANY OTHERS
CONTAINED IN THIS MANUAL FOR CROWN PRODUCTS.
9/90
NORTH AMERICA
SUMMARY OF WARRANTY
The Crown Audio Division of Crown International, Inc., 1718 West Mishawaka
Road, Elkhart, Indiana 46517-4095 U.S.A. warrants to you, the ORIGINAL
PURCHASER and ANY SUBSEQUENT OWNER of each NEW Crown product,
for a period of three (3) years from the date of purchase by the original purchaser
(the “warranty period”) that the new Crown product is free of defects in materials
and workmanship. We further warrant the new Crown product regardless of the
reason for failure, except as excluded in this Warranty.
ITEMS EXCLUDED FROM THIS CROWN WARRANTY
This Crown Warranty is in effect only for failure of a new Crown product which
occurred within the Warranty Period. It does not cover any product which has
been damaged because of any intentional misuse, accident, negligence, or loss
which is covered under any of your insurance contracts. This Crown Warranty
also does not extend to the new Crown product if the serial number has been
defaced, altered, or removed.
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 interest, insurance, closing costs, and other finance charges less a
reasonable depreciation on the product from the date of original purchase.
Warranty work can only be performed at our authorized service centers or at the
factory. We will remedy the defect and ship the product from the service center
or our factory within a reasonable time after receipt of the defective product at our
authorized service center or our factory. All expenses in remedying the defect,
including surface shipping costs in the United States, will be borne by us. (You
must bear the expense of shipping the product between any foreign country and
the port of entry in the United States and all taxes, duties, and other customs fees
for such foreign shipments.)
HOW TO OBTAIN WARRANTY SERVICE
You must notify us of your need for warranty service not later than ninety (90)
days after expiration of the warranty period. All components must be shipped in
a factory pack, which, if needed, may be obtained from us free of charge.
Corrective action will be taken within a reasonable time of the date of receipt of
the defective product by us or our authorized service center. If the repairs made
by us or our authorized service center are not satisfactory, notify us or our
authorized service center immediately.
DISCLAIMER OF CONSEQUENTIAL AND INCIDENTAL DAMAGES
YOU ARE NOT ENTITLED TO RECOVER FROM US ANY INCIDENTAL
DAMAGES RESULTING FROM ANY DEFECT IN THE NEW CROWN
PRODUCT. THIS INCLUDES ANY DAMAGE TO ANOTHER PRODUCT OR
PRODUCTS RESULTING FROM SUCH A DEFECT. SOME STATES DO
NOT ALLOW THE EXCLUSION OR LIMITATIONS OF INCIDENTAL OR
CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATION OR
EXCLUSION MAY NOT APPLY TO YOU.
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 later than ninety
(90) days after expiration of the warranty period.
THIS STATEMENT OF WARRANTY SUPERSEDES ANY OTHERS
CONTAINED IN THIS MANUAL FOR CROWN PRODUCTS.
9/90
Telephone: [phone]. Facsimile: 219-294-8301
Telephone: [phone]. Facsimile: 219-294-8301
THREE YEAR
FULL WARRANTY
YEAR
3
YEAR
3

The information furnished in this manual does not include all of the details of design, production, or variations of the
equipment. Nor does it cover every possible situation which may arise during installation, operation or mainte-
nance. If your unit bears the name “Amcron,” please substitute it for the name “Crown” in this manual. If you need
special assistance beyond the scope of this manual, please contact our Technical Support Group.
Crown Audio Technical Support Group
Plant 2 SW, 1718 W. Mishawaka Rd., Elkhart, Indiana 46517 U.S.A.
Phone: [phone] (North America, Puerto Rico and Virgin Islands) or 219-294-8200
Fax: [phone] Fax Back (North America only): 800-294-4094 or 219-293-9200
Fax Back (International): 219-294-8100 Internet: http://www.crownaudio.com
IMPORTANT
CLASS 1 OUTPUT WIRING REQUIRED.
COMPLY WITH LOCAL ELECTRICAL CODES
WHEN WIRING THIS DEVICE.
Printed on
recycled paper.
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.
WARNING
TO REDUCE THE RISK OF ELECTRIC
SHOCK, DO NOT EXPOSE THIS
EQUIPMENT TO RAIN OR MOISTURE!
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 stron-
gest just above and below the unit.
If an equipment rack is used, we recommend locat-
ing the amplifier(s) in the bottom of the rack and the
preamplifier or other sensitive equipment at the top.
C A U T I O N
RISK OF ELECTRIC SHOCK
DO NOT OPEN
TO PREVENT ELECTRIC SHOCK DO
NOT REMOVE TOP OR BOTTOM
COVERS. NO USER SERVICEABLE
PARTS INSIDE. REFER SERVICING TO
QUALIFIED SERVICE PERSONNEL.
DISCONNECT POWER CORD BE-
FORE REMOVING REAR INPUT
MODULE TO ACCESS GAIN SWITCH.
A V I S
RISQUE DE CHOC ÉLECTRIQUE
N’OUVREZ PAS
À PRÉVENIR LE CHOC ÉLECTRIQUE
N’ENLEVEZ PAS LES COUVERCLES. IL
N’Y A PAS DES PARTIES
SERVICEABLE À L’INTÉRIEUR. TOUS
REPARATIONS DOIT ETRE FAIRE PAR
PERSONNEL QUALIFIÉ SEULMENT.
DÉBRANCHER LA BORNE AVANT
D’OUVRIR LA MODULE EN ARRIÈRE.

Macro-Tech 3600VZ Power Amplifier
Page 4 Reference Manual
Important Safety Instructions
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 ac-
cordance with the manufacturer’s instructions.
8) Do not install near any heat sources such as radia-
tors, 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 recep-
tacles, and the point where they exit from the appara-
tus.
11) Only use attachments/accessories specified by the
manufacturer.
12) Use only with a cart, stand, bracket, or table speci-
fied 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 power-supply 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 ex-
pose this apparatus to rain or moisture.

Macro-Tech 3600VZ Power Amplifier
Page 5
Reference Manual
CONTENTS
1 Welcome ............................................................................ 7
1.1 Unpacking ................................................................... 7
1.2 Features ....................................................................... 8
2 Facilities ............................................................................ 9
3 Installation ....................................................................... 11
3.1 Mounting ................................................................... 11
3.2 Cooling ...................................................................... 11
3.3 Wiring ........................................................................ 12
3.3.1 Stereo (Two-Channel) Operation ...................... 12
3.3.2 Bridge-Mono Operation ................................... 13
3.3.3 Parallel-Mono Operation .................................. 14
3.3.4 Input Connection ............................................. 15
3.3.5 Output Connection .......................................... 17
3.3.6 Additional Load Protection ............................... 19
3.3.7 AC Power Requirements .................................. 19
4 Operation ......................................................................... 20
4.1 Precautions ................................................................ 20
4.2 Indicators ................................................................... 20
4.3 Protection Circuits ...................................................... 21
4.3.1 Output Device Emulation Protection
(ODEP) .... 21
4.3.2 Standby Mode ................................................. 22
4.3.3 Transformer Thermal Protection ....................... 22
4.3.4 Circuit Breaker ................................................. 22
4.4 Controls ..................................................................... 23
4.5 Filter Cleaning ............................................................ 24
5 Technical Information ...................................................... 25
5.1 Overview ................................................................... 25
5.2 VZ Power ................................................................... 25
5.2.1 Background .................................................... 25
5.2.2 The VZ Supply ................................................. 26
5.3 Circuit Theory ............................................................ 26
5.3.1 Stereo Operation ............................................. 26
5.3.2 Bridge-Mono Operation ................................... 28
5.3.3 Parallel-Mono Operation .................................. 28
6 Specifications .................................................................. 29
7 AC Power Draw and Thermal Dissipation ....................... 36
8 Accessories ..................................................................... 37
8.1 PIP Modules .............................................................. 37
8.2 Level Control Security Kit ........................................... 39
9 Service ............................................................................. 40
9.1 Worldwide Service ..................................................... 40
9.2 North American Service ............................................. 40
9.2.1 Service at a North American Service Center .... 40
9.2.2 Factory Service ............................................... 40

Macro-Tech 3600VZ Power Amplifier
Page 6 Reference Manual
ILLUSTRATIONS
1.1 Macro-Tech 3600VZ Amplifier .................................................... 7
2.1 Front Facilities ........................................................................... 9
2.2 Rear Facilities ......................................................................... 10
3.1 Mounting Dimensions .............................................................. 11
3.2 Top View of a Rack-Mounted Unit ............................................ 11
3.3 Proper Air Flow in a Rack Cabinet ........................................... 11
3.4 Stereo Wiring .......................................................................... 12
3.5 Bridge-Mono Wiring ................................................................ 13
3.6 Parallel-Mono Wiring ............................................................... 14
3.7 Unbalanced Input Wiring ......................................................... 15
3.8 Balanced Input Wiring ............................................................. 15
3.9 Balanced and Unbalanced Phone Plugs ................................. 15
3.10 Subsonic Filter Capacitors ...................................................... 16
3.11 Unbalanced RFI Filters ............................................................ 16
3.12 Balanced RFI Filters ................................................................ 16
3.13 Wire Size Nomograph ............................................................. 17
3.14 Inductive Load (Transformer) Network ..................................... 18
3.15 Loudspeaker Fuse Nomograph ............................................... 19
4.1 Indicators ................................................................................ 20
4.2 Macro-Tech Indicator States .................................................... 21
4.3 Input Sensitivity and Ground Lift Switches ............................... 23
5.1 A Typical Power Supply ........................................................... 26
5.2 Music Waveforms are Complex ............................................... 26
5.3
VZ Supply in Parallel Mode ..................................................... 26
5.4 VZ Supply in Series Mode ....................................................... 26
5.5 Circuit Block Diagram ............................................................. 27
6.1 Minimum Power Matrix ............................................................ 32
6.2 Maximum Power Matrix ........................................................... 33
6.3 Typical Frequency Response .................................................. 34
6.4 Typical Damping Factor .......................................................... 34
6.5 Typical Output Impedance ...................................................... 34
6.6 Typical Phase Response ......................................................... 35
6.7 Typical Crosstalk ..................................................................... 35
7.1 Power Draw, Current Draw and Thermal Dissipation ................ 36
8.1 Installing a PIP Module ............................................................ 37
8.2 PIP2 Adapter Connection ........................................................ 37
8.3 Installing a PIP2 Module .......................................................... 37
8.4 Installing a Level Control Shaft Lock ........................................ 39

Macro-Tech 3600VZ Power Amplifier
Page 7
Reference Manual
Fig. 1.1 Macro-Tech 3600VZ Amplifier
1 Welcome
Congratulations on your purchase of the Macro-Tech
®
3600VZ professional power amplifier. It is the first audio
amplifier to offer Crown’s patented Variable Impedance
(VZ®) power supplies. The new power supplies, along
with new semiconductor technology, enable the Macro-
Tech 3600VZ to pack more power into a mere 3½ inches
of vertical rack space than ever before. Because it’s a
Macro-Tech , you have the added benefit of PIP ™com-
patibility for access to custom input modules and
ODEP
®protection to keep the show going long after
other amplifiers would fail (see the Section 8 for avail-
able input modules).
This manual will help you successfully install and use
your new amplifier. We strongly recommend you read
all instructions, warnings and cautions contained within.
Be sure to read Sections 3.3.2 and 3.3.3 if you plan to
use the amplifier in one of its two mono modes. Also for
your protection, please send in your warranty registra-
tion card today and save your bill of sale since it is your
official proof of purchase.
1.1 Unpacking
Please unpack and inspect your new amplifier for any
damage that may have occurred during transit. If dam-
age is found, notify the transportation company imme-
diately. Only you, the consignee, may initiate a claim
with the carrier for damage resulting during shipment.
Crown will be happy to cooperate fully as needed. Save
the shipping carton as evidence of damage for the
shipper’s inspection.
Even if the unit arrived in perfect condition, as most do,
save all packing materials so you will have them if you
ever need to transport the unit. NEVER SHIP THE UNIT
WITHOUT THE FACTORY PACK.

Macro-Tech 3600VZ Power Amplifier
Page 8 Reference Manual
1.2 Features
The Macro-Tech 3600VZ amplifier uses the latest tech-
nology and miniaturized design to deliver the highest
power and value for its size, weight and price. Crown’s
Grounded Bridge
™output and patented
ODEP protec-
tion circuitry combine to provide performance and reli-
ability that surpass all conventional amplifier designs.
Macro-Tech amplifiers also have an independent high
voltage power supply for each channel. This design
provides ultra-low crosstalk specifications and makes it
possible to treat each channel as a separate amplifier.
Features:
❏Crown’s
Grounded Bridge
™
circuitry generates in-
credible voltage swings while avoiding stressful out-
put transistor configurations common to
conventional amplifiers. The results are lower distor-
tion and superior reliability.
❏Patented ODEP (Output Device Emulation Protec-
tion) circuitry compensates for overheating and over-
load to keep the amplifier working long after others
would fail.
❏ IOC
®(Input/Output Comparator) circuitry immedi-
ately alerts of any distortion exceeding 0.05%, pro-
viding dynamic proof of performance .
❏ PIP (Programmable Input Processor) connector ac-
cepts accessories that tailor your amplifier to suit in-
dividual applications.
❏Two mono modes (Bridge-Mono and Parallel-Mono)
for driving a wide range of load impedances.
❏Very low harmonic and intermodulation distortion re-
sult in the best dynamic transfer function in the in-
dustry.
❏High damping factor provides superior control over
low frequency drivers for a clean, accurate low end.
❏An articulated VZ power supply for each channel
provides excellent crosstalk characteristics and the
best power matching to your load.
❏Full protection against shorted outputs, open cir-
cuits, mismatched loads, general overheating, high
frequency overloads and internal faults; loudspeaker
protection against low frequency and DC output.
❏Extra rugged, extruded aluminum front panel with
ODEP and Signal Presence/ IOC indicators for each
channel, as well as an Enable Indicator.
❏Separate voltage supplies for each channel provide
low crosstalk and improved reliability.
❏Efficient heat sinks and a self-contained forced air
cooling system dissipate heat quickly and evenly to
prevent overheating, prolong component life and de-
liver greater power output.
❏Balanced inputs and adjustable front panel level
controls.
❏31 detents in the level controls reduce the likelihood
of settings being inadvertently disturbed.
❏Ground lift switch to isolate chassis and phone jack
audio input grounds.
❏Multiple dual binding posts provide easy and versa-
tile output connection.
❏Internal three position input sensitivity switch pro-
vides settings of 0.775 volts and 1.4 volts for rated
output, and 26 dB voltage gain.
❏Mounts in a standard 19 inch (48.3 cm) equipment
rack with rear support, or units can be stacked.
❏All specifications are guaranteed for the duration of
the warranty period.
❏Units in North America and other select countries
are covered by a three year “No-Fault” full warranty
which completely protects your investment and
guarantees its specifications.

Macro-Tech 3600VZ Power Amplifier
Page 9
Reference Manual
Fig. 2.1 Front Facilities
2 Facilities
A. Dust Filter
The dust filters remove large particles from the air at the
air intake. Check filters regularly to be sure they do not
become clogged. The filter elements can be easily re-
moved for cleaning by gently pulling them away from
the front panel (see Sections 3.2 and 4.5).
B. Level Controls
The level for each channel is set with these convenient
controls mounted on the front panel. Each level control
has 31 detents for precise adjustment (see Section 4.4).
A security option is available to prevent tampering (see
Section 8.2).
C. Signal / IOC Indicators
The presence of an audio signal and the distortion level
of each channel is represented by these green multi-
function indicators. As signal presence indicators, they
flash with normal intensity in sync with the output audio
signal to indicate its presence. As IOC (Input/Output
Comparator) indicators, they compare the waveform of
the input signal to that of the output. They flash brightly
with a 0.1 second hold delay if there is a difference (or
distortion) of 0.05% or more. Another IOC function is to
indicate input overload. If the input signal is too large
the indicators will flash brightly (with a 0.5 second hold
delay) to indicate input clipping distortion. Note: The
Channel 2 IOC indicator will stay on in Parallel-Mono
mode (refer to Section 4.2).
D. ODEP Indicators
During normal operation of the Output Device Emula-
tion Protection circuitry, these indicators glow brightly
to show the presence of reserve thermodynamic en-
ergy. They dim proportionally as energy reserves de-
crease. In the event that energy reserves are depleted,
the indicators turn off and ODEP proportionally limits
output drive so the amplifier can safely continue to op-
erate even under severe conditions. These indicators
can also help to identify more unusual operating prob-
lems (see Section 4.2).
E. Enable Indicator
This indicator lights when the amplifier has been “en-
abled” or turned on, and AC power is available (see
Section 4.2).
F. Enable Switch
Depress this push-button to turn the amplifier on or off.
When turned on, the output is muted for approximately
four seconds to protect your system from start-up tran-
sients. (This delay can be changed. Contact the Crown
Technical Support Group for details.)
G. Power Cord
All 120 VAC, 60 Hz North American units include a
NEMA TT30P plug. These units also include 30-amp
(10 AWG) line cord. Other units are equipped with a
power cord and plug that is appropriate for the voltage
requirements of the amplifier.
H. Stereo/Mono Switch
The three operating modes of this amplifier are
controlled by this switch. Stereo mode is available for
normal two-channel operation. Bridge-Mono mode is
available to drive a single load with an impedance equal
to or greater than 4 ohms. Parallel-Mono mode is

Macro-Tech 3600VZ Power Amplifier
Page 10 Reference Manual
Fig. 2.2 Rear Facilities
available to drive a single load with an impedance less
than 4 ohms. Important: Do NOT change this switch
unless the amplifier is first turned off (see Section
3.3).
I. Reset Buttons (PUSH TO RESET)
These reset buttons are used to reset the breakers that
safeguard the power supplies from overload (see
Section 4.3).
J. PIP Module
Versatile Programmable Input Processor modules pro-
vide flexible expansion features that can be added to
customize the amplifier. PIP modules plug into the con-
nector inside the back panel of the amplifier. A PIP
module’s input connectors are placed in parallel with
the input phone jacks. The P.I.P.®-FX is included as a
standard feature to provide balanced XLR inputs. It has
no internal circuitry and can be used along with the in-
put phone jacks to facilitate “daisy chaining” multiple
amplifiers. See Section 8 for a list of available PIP mod-
ules.
K. Balanced Phone Jack Inputs
A balanced ¼ inch phone jack is provided for input to
each channel. They may be used with either balanced
(tip, ring and sleeve) or unbalanced (tip and sleeve)
input wiring (refer to Section 3.3). Because these inputs
are in parallel with the PIP connector, they should not be
used as inputs if the installed PIP has active circuitry.
Caution: The Channel 2 input should NOT be used in
either mono mode.
L. Ground Lift Switch
The input signal ground may be isolated from the AC
ground with this switch to help prevent the hum created
by unwanted ground loops. It affects only the input
phone jacks. It has no affect on the PIP module’s XLR
input connectors. Activating the switch inserts an im-
pedance between the sleeve of each phone input jack
and the circuit ground.
M. Balanced XLR Inputs
A balanced 3-pin female XLR connector is provided for
input to each channel by the P.I.P.-FX, a standard fea-
ture of your amplifier. The XLR connectors are in parallel
with the amplifier’s phone jacks. Because there is no
active circuitry on the PIP , the XLR connectors can be
used at the same time as the phone input jacks for
“daisy chaining” multiple amplifiers. Caution: The
Channel 2 input should NOT be used in either mono
mode.
N. Output Jacks
Two pairs of dual binding posts are provided for the
output of each channel so multiple loudspeakers can
be connected easily. The connectors accept bare wire
or spade lugs.
❑Input Sensitivity Switch
The three position input sensitivity switch inside the
amplifier can be accessed by removing the PIP mod-
ule. Settings include 0.775 volts and 1.4 volts for rated
output, and 26 dB voltage gain (see Section 4.4).

Macro-Tech 3600VZ Power Amplifier
Page 11
Reference Manual
3 Installation
3.1 Mounting
Macro-Tech amplifiers are designed for standard 19
inch (48.3 cm) rack mounting and “stack” mounting
without a cabinet. In a rack cabinet, it is best to mount
them one on top of the other. This provides efficient air
flow and enables each unit to support the one above.
Important: Due to its weight, the back of the amplifier
should be supported.
Fig. 3.2 Top View of a Rack-Mounted Unit
If the air supply is unusually dusty, it may be necessary
pre-filter it using commercial furnace filters, etc., to pre-
vent rapid loading of the unit’s own air filter. When
needed, the unit’s filter can be cleaned with mild dish
detergent and water (see Section 4.5).
When mounting the amplifier in a rack cabinet, the side
walls of the rack should be at least 2 inches (5 cm) away
from the chassis as shown in Figure 3.2.
Tip: An easy way to verify adequate cooling is to ob-
serve the ODEP indicators with the amplifier operating
under worst-case conditions. If the indicators dim, ad-
ditional cooling is recommended.
If your rack cabinet has a front door that could block air
flow to the amplifier’s air intakes, you must provide ad-
equate air flow either with a grille in the door or by pres-
surizing the air behind the door. Wire grilles are
recommended over perforated panels because they
have larger openings and cause less restriction.
A good choice for increased air flow behind a rack cabi-
net door is to mount one or more “squirrel cage” blow-
ers in the rack (Option 1 below). The blower is mounted
at the bottom of the rack so it blows outside air into the
space between the door and the front of the amplifiers.
This blower should not blow air into or take air out of the
space behind the amplifiers. For racks without a door,
mount a blower at the top of the rack so air is drawn out
the back (Option 2 below). The blower must provide air
flow that exceeds the sum of the air flow required by the
individual amplifiers.
Fig. 3.3 Proper Air Flow in a Rack Cabinet
Fig. 3.1 Mounting Dimensions
3.2 Cooling
NEVER block the amplifier’s side vents and front air in-
take. Under demanding conditions, there should be a
minimum air flow of 45 cubic feet (1.3 cubic meters) per
minute per amplifier. When mounted in a rack, all empty
spaces should be covered with blank panels to prevent
improper air flow. The amplifier’s air flow should be aug-
mented with a rack cooling system if its load is less than
4 ohms and it must operate at consistently high output
levels as in concert sound reinforcement.
AIR
FLOW
AIR FLOW
AMPLIFIER
(TOP VIEW)
RACK
CABINET
16 in
40.6 cm
2 in
(5cm)
MIN.
IMPORTANT: Be sure rear of amplifier
is securely mounted to rack.
17 in
43.2 cm
AIR
FLOW
BLOWER
(OPTION 2)
BLOWER
(OPTION 1)
AIR
FLOW
FRONT
OF
RACK
DOOR
AIR
FLOW
EQUIPMENT
RACK
(SIDE VIEW)

Macro-Tech 3600VZ Power Amplifier
Page 12 Reference Manual
Fig. 3.4 Stereo Wiring
3.3 Wiring
The following section describes common ways to in-
stall your amplifier in a sound system. The input and
output terminals are located on the rear panel. Please
use care when making connections, selecting signal
sources and controlling the output level. The load you
save may be your own! Crown assumes no liability for
damaged loads resulting from careless amplifier use or
deliberate overpowering.
CAUTION: Always remove power from the unit and
turn the level controls off when making or breaking
connections—especially if the load is a loudspeaker
system. This reduces the chance of loud blasts or dam-
aged loudspeakers.
Macro-Tech amplifiers may be operated in one of three
modes (Stereo, Bridge-Mono, and Parallel-Mono) by
switching the Stereo/Mono switch on the rear panel.
There are VERY IMPORTANT wiring differences be-
tween these three modes which are discussed next.
3.3.1 Stereo (Two-Channel) Operation
The installation is very intuitive in Stereo mode. The in-
put of Channel 1 feeds the output of the same channel
as does the input of Channel 2. To put the amplifier into
Stereo mode, first turn the amplifier off, then slide the
Stereo/Mono switch to the center position, and properly
connect the output wiring as shown in Figure 3.4. Two
sets of binding posts are provided for each channel to
facilitate easy connection of multiple speakers to each
channel. Observe correct loudspeaker polarity and be
very careful not to short the outputs of one channel to
that of the other channel while in Stereo mode.
CAUTION: In Stereo mode, never parallel the two
outputs by directly tying them together or parallel-
ing them with the output of any other amplifier.
Such connection does not result in increased power out-
put and can cause premature activation of the protec-
tion circuitry to prevent overheating.

Macro-Tech 3600VZ Power Amplifier
Page 13
Reference Manual
Fig. 3.5 Bridge-Mono Wiring
3.3.2 Bridge-Mono Operation
Bridge-Mono mode is intended for driving loads with a
net impedance of 4 ohms or greater. (See Parallel-Mono
if the load is less than 4 ohms.) Installing the amplifier in
Bridge-Mono mode is very different from the other
modes and requires special attention.
To put the amplifier in Bridge-Mono mode, turn the am-
plifier off and slide the Stereo/Mono switch toward the
right (as you face the back of the amplifier). Both out-
puts receive the signal from Channel 1 with the output
of Channel 2 inverted so it can be bridged with the
Channel 1 output. DO NOT USE THE CHANNEL 2 IN-
PUT or the signal level and quality may be greatly de-
graded. Keep the Level control of Channel 2 turned
completely down (counterclockwise).
Note: The input jack and level control for Channel 2 are
not defeated in Bridge-Mono mode. Any signal fed into
Channel 2 may work against and add to or distort the
signal in Channel 1.
Connect the load across the Channel 1 and 2 red bind-
ing posts with the positive lead from the load attaching
to a red post of Channel 1 and the negative lead of the
load attaching to a red post of Channel 2 as shown in
Figure 3.5. THE TWO BLACK BINDING POSTS ARE
NOT USED AND SHOULD NOT BE SHORTED. The
load must be balanced (neither side shorted to ground).
CAUTION: Be certain all equipment (meters,
switches, etc.) connected to the mono output is bal-
anced. To prevent oscillations, both sides of the line
must be isolated from the input grounds.

Macro-Tech 3600VZ Power Amplifier
Page 14 Reference Manual
Fig. 3.6 Parallel-Mono Wiring
3.3.3 Parallel-Mono Operation
Parallel-Mono mode is used to drive loads with a total
impedance of less than 4 ohms. (See Bridge-Mono if
the load is 4 ohms or greater.) Installing the amplifier in
Parallel-Mono mode is very different from the other
modes and requires special attention.
CAUTION: Do not attempt to operate in Stereo or
Bridge-Mono mode until the Parallel-Mono jumper
is first removed. Failure to do so will definitely cause
inefficient operation, high distortion and excessive
heating.
To put the amplifier in Parallel-Mono mode, first turn it
off, then slide the Stereo/Mono switch to the left (as you
face the back). Connect the input signal to Channel 1
only. DO NOT USE THE CHANNEL 2 INPUT or the sig-
nal level and quality may degrade greatly. Turn off the
Channel 2 Level control (full counterclockwise).
Note: It is normal for the IOC indicator of Channel 2 to
stay on in Parallel-Mono mode.
The input jack and Level control of Channel 2 are not
defeated in Parallel-Mono mode. Any signal fed into
Channel 2 may work against and add to or distort the
signal in Channel 1.
Install a jumper wire between the red binding posts of
both Channel 1 and 2 that is at least 14 gauge in size.
Then, connect the load to the output of Channel 1 as
shown in Figure 3.6. The positive lead from the load
connects to the red binding post of Channel 1 and the
negative lead from the load connects to the black bind-
ing post of Channel 1.
CAUTION: Remove the jumper wire before chang-
ing to any mode except Parallel-Mono.

Macro-Tech 3600VZ Power Amplifier
Page 15
Reference Manual
3.3.4 Input Connection
Both the balanced XLR and phone jack inputs have a
nominal impedance of 20 k ohms (10 K ohms with un-
balanced wiring) and will accept the line-level output of
most devices. Female XLR input connectors are pro-
vided on the standard P.I.P.-FX input module (other
PIP
modules are described in Section 8.1). Correct input
wiring will depend on two factors: (1) whether the input
signals are balanced or unbalanced, and (2) whether
the signal source floats or has a ground reference. Fig-
ures 3.7 and 3.8 show the recommended connection
techniques for each type of signal source.
The amplifier’s built-in ¼-inch phone jack input connec-
tors can be wired similarly for balanced or unbalanced,
floating or ground-referenced sources. They have a
standard tip-ring-sleeve (TRS) configuration: the tip is
Fig. 3.8 Balanced Input Wiring
Fig. 3.7 Unbalanced Input Wiring Fig. 3.9 Balanced and Unbalanced Phone Plugs
positive (+), the ring is negative (–) and the sleeve is
ground (see Figure 3.9). Wiring for various sources fol-
lows the XLR wiring guidelines shown in Figures 3.7
and 3.8.
The phone jacks should not be used as inputs when a
PIP module with active circuitry is installed. The phone
jacks are in parallel with the output of the PIP module,
so an input signal connected to the phone jacks can
feed backwards into the active circuitry of the PIP and
cause undesirable distortion. You can use the phone
jacks for signal input with any of the following PIP mod-
ules installed: P.I.P.-FX, P.I.P.-BB, P.I.P.-FMX, P.I.P.-FXQ
and P.I.P.-FPX. All other PIP modules have active cir-
cuitry and should not be installed if you plan to connect
input signals to the phone jacks. The phone jacks can
always be used as “daisy chain” outputs to feed post-
processed signals from the PIP to the inputs of other
amplifiers.
Please follow the instruction in Section 3.3.2 and 3.3.3 if
the amplifier will be used in either Bridge-Mono or Par-
allel-Mono mode. Remember, do not use the Channel 2
input in either mono mode.

Macro-Tech 3600VZ Power Amplifier
Page 16 Reference Manual
SOLVING INPUT PROBLEMS
Sometimes large subsonic (subaudible) frequencies
are present in the input signal. These can damage loud-
speakers by overloading or overheating them. To at-
tenuate such frequencies, place a capacitor in series
with the input signal line. The graph in Figure 3.10
shows some capacitor values and how they affect the
frequency response. Use only low-leakage paper, my-
lar or tantalum capacitors.
For balanced input wiring use one of the examples in
Figure 3.12. Filters A, B and C correspond to the unbal-
anced filters above. Filter D also incorporates the sub-
sonic filter described previously.
Fig. 3.11 Unbalanced RFI Filters
Another problem to avoid is the presence of large lev-
els of radio frequencies or RF in the input signal. Al-
though high RF levels may not pose a threat to the
amplifier, they can burn out tweeters or other loads that
are sensitive to high frequencies. Extremely high RF lev-
els can also cause your amplifier to prematurely acti-
vate its protection circuitry, resulting in inefficient
operation. RF can be introduced into the signal by local
radio stations and from the bias signal of many tape
recorders. To prevent high levels of input RF, install an
appropriate low-pass filter in series with the the input
signal. Some examples of unbalanced wiring for low-
pass filters are shown in Figure 3.11.
Fig. 3.10 Subsonic Filter Capacitors
Fig. 3.12 Balanced RFI Filters
Tip: The P.I.P.-FX included with your amplifier has plenty
of room on its circuit board for input filters.
A third problem to avoid is hum. The two most common
sources of hum in an audio system are inductive cou-
pling and ground loops.
Inductive coupling can occur when input cables are
subjected to a magnetic field from a power cord or
power transformer. One way to prevent inductive cou-
pling is to lace the input cables together along their
length and route them as far away as possible from
power transformers and power cords. The use of
Input Wiring Tips
1. Use only shielded cable. Cables with
higher density shields are better. Spiral
wrapped shield is not recommended.
2. When using unbalanced lines, keep the
cables as short as possible. Avoid cable
lengths greater than 10 feet (3 meters).
3. Do not run signal cables together with
high-level wiring such as loudspeaker wires
or AC cords. This greatly lessens the chance
of hum or noise being induced into the input
cables.
4. Turn the entire system off before changing
connections. Turn level controls down
completely before powering the system back
up. Crown is not liable for damage incurred
when any transducer or component is
overdriven.
+
–
Balanced In
910 Ω
.003
Fµ
.015
Fµ
.018
Fµ
1.8 mH
2.5 mH
A
C
B
.015
Fµ
1.8 mH
D
Balanced Out
+
–
910 Ω
1.8 mH
2.5 mH
1.8 mH
+
–
Balanced In Balanced Out
+
–
+
–
Balanced In Balanced Out
+
–
+
–
Balanced In Balanced Out
+
–
0.47 Film
0.47 Film
1 Hz 10 Hz 100 Hz 1 kHz 10 kHz
dB
0
–5
–10
–15
1 F
µ
.1 F
µ
.05 F
.01 F
µ
µ
Frequency
4 kHz 10 kHz 40 kHz 100 kHz
Frequency
dB
0
–10
–20
A
B
C
6 dB/octave
12 dB/octave
To
Amp
GND
To
Amp
GND
To
Amp
GND
Source
1.8 K ohm
.003
Fµ
.015
F
µ
.018
Fµ
3.9 mH
5 mH
600 ohm
Source
R
600 ohm
Source
R
A
C
B
Note: A low source impedance (R) can be
increased to 600 ohms with an appropriate resistor.

Macro-Tech 3600VZ Power Amplifier
Page 17
Reference Manual
shielded pair cable is another effective way to reduce
or eliminate hum resulting from inductive coupling.
Ground loops often result when two or more devices
are improperly grounded. This causes undesirable
stray currents that may produce hum in the output. The
best way to avoid ground loops is to ensure that all sys-
tem devices are plugged into the same power strip. In
addition, make sure that all cable shields are grounded
at one end only.
Input and output grounds are sometimes tied together
for testing or metering. This can cause feedback oscil-
lation from load current in the test loop. In some sys-
tems, even the AC power line may provide this
feedback path. Proper grounding, input isolation and
isolation of common AC devices in the system is good
practice.
3.3.5 Output Connection
Consider the power handling capacity of your load be-
fore connecting it to the amplifier. Crown is not liable for
damage incurred at any time due to overpowering. Fus-
ing loudspeaker lines is highly recommended (see Sec-
tion 3.3.6). Also, please pay close attention to the
precautions provided in Section 4.1.
resistance increases. This is very important because
the amplifier’s excellent damping factor can easily be
negated by insufficient loudspeaker cables.
Use the nomograph in Figure 3.13 and the procedure
that follows to find the recommended wire gauge (AWG
or American Wire Gauge) for your system.
Fig. 3.13 Wire Size Nomograph
Use Good Connectors
1. To prevent possible shorts, do not expose
the loudspeaker cable connectors.
2. Do not use connectors that might acci-
dentally tie two channels together when mak-
ing or breaking connections (for example, a
standard three-wire stereo phone plug).
3. Connectors that can be plugged into AC
power receptacles should never be used.
4. Connectors with low current-carrying ca-
pacity should not be used.
5. Connectors with any tendency to short
should never be used.
HOW TO DETERMINE
APPROPRIATE WIRE GAUGE
It is important to use loudspeaker cables with sufficient
gauge (thickness) for the length being used. The resis-
tance introduced by inadequate loudspeaker cables
will reduce both the output power and the motion con-
trol of the loudspeakers. The latter problem occurs be-
cause the damping factor decreases as the cable
40
30
20
15
10
9
8
7
6
5
4
3
2
1
2
5
10
20
50
100
.04
.06
.1
.2
.4
.6
1
2
4
6
10
20
40
5
10
20
50
1
2
100
200
500
1000
2000
5000
8000
5000
1000
500
100
50
10
5
1
.5
.1
.05
.01
#28
#26
#24
#22
#20
#18
#16
#14
#12
#10
#8
#6
#4
#2
#0
#00
#0000
R
LOAD
RESISTANCE
(ohms)
L
R
R
DAMPING
FACTOR
L
S
R
SOURCE
RESISTANCE
(ohms)
S
2-COND.
CABLE
(feet)
COPPER
WIRE
(AWG)
(ohms/1000 ft.)
Example Shown:
R = 8 ohms; R = 0.016 ohms or D.F. = 500;
Cable Length = 10 ft.; answer: #8 wire
LS
1
0.5
200
500
1,000
2,000
20,000
5,000
10,000
.01
.001
.02
.004
.006
.002
.0004
.0006
.0002
0.6
0.7
0.8
1.5
0.9

Macro-Tech 3600VZ Power Amplifier
Page 18 Reference Manual
2. Avoid using shielded loudspeaker cable.
3. Avoid long cable runs where the loudspeaker
cables from different amplifiers share a common
cable tray or cable jacket.
4. Never connect the amplifier’s input and output
grounds together.
5. Never tie the outputs of multiple amplifiers to-
gether.
6. Keep loudspeaker cables well separated from
input cables.
7. Install a low-pass filter on each input line (similar
to the RF filters described in Section 3.3.4.
8. Install input wiring according to the instructions
in Section 3.3.4.
Another problem to avoid is the presence of large sub-
sonic currents when primarily inductive loads are
used. Examples of inductive loads are 70-volt trans-
formers and electrostatic loudspeakers.
Inductive loads can appear as a short circuit at low fre-
quencies. This can cause the amplifier to produce large
low-frequency currents and activate its protection cir-
cuitry. Always take the precaution of installing a high-
pass filter in series with the amplifier’s input when
inductive loads are used. A 3-pole, 18 dB per octave
filter with a –3 dB frequency of 50 Hz is recommended
(depending on the application, an even higher –3 dB
frequency may be desirable). Such a filter is described
with subsonic frequency problems in Section 3.3.4.
Another way to prevent the amplifier from prematurely
activating its protection systems and to protect induc-
tive loads from large low-frequency currents is to con-
nect a 590 to 708 µF nonpolarized capacitor and 4-ohm,
20-watt resistor in series with the amplifier’s output and
the positive (+) lead of the transformer. The circuit
shown below uses components that are available from
most electronic supply stores.
Fig. 3.14 Inductive Load (Transformer) Network
1. Note the load resistance of the loudspeakers connected
to each channel of the amplifier. Mark this value on the
“Load Resistance” line of the nomograph.
2. Select an acceptable damping factor and mark it on the
“Damping Factor” line. Your amplifier can provide an ex-
cellent damping factor of 1,000 from 10 to 400 Hz in Ste-
reo mode with an 8-ohm load. In contrast, typical damp-
ing factors are 50 or lower. Higher damping factors yield
lower distortion and greater motion control over the loud-
speakers. A common damping factor for commercial ap-
plications is between 50 and 100. Higher damping fac-
tors may be desirable for live sound, but long cable
lengths often limit the highest damping factor that can be
achieved practically. (Under these circumstances,
Crown’s
IQ System
®is often used so amplifiers can be
monitored and controlled when they are located very
near the loudspeakers.) In recording studios and home
hi-fi, a damping factor of 500 or more is very desirable.
3. Draw a line through the two points with a pencil, and
continue until it intersects the “Source Resistance” line.
4. On the “2-Cond. Cable” line, mark the length of the cable
run.
5. Draw a pencil line from the mark on the “Source Resis-
tance” line through the mark on the “2-Cond. Cable” line,
and on to intersect the “Annealed Copper Wire” line.
6. The required wire gauge for the selected wire length and
damping factor is the value on the “Annealed Copper
Wire” line.
Note: Wire size increases as the AWG gets
smaller .
7. If the size of the cable exceeds what you want to use,
(1) find a way to use shorter cables, like using the
IQ Sys-
tem , (2) settle for a lower damping factor, or (3) use more
than one cable for each line. Options 1 and 2 will require
the substitution of new values for cable length or damp-
ing factor in the nomograph. For option 3, estimate the
effective wire gauge by subtracting 3 from the apparent
wire gauge every time the number of conductors of equal
gauge is doubled. So, if #10 wire is too large, two #13
wires can be substituted, or four #16 wires can be used
for the same effect.
SOLVING OUTPUT PROBLEMS
Sometimes high-frequency oscillations occur which
can cause your amplifier to prematurely activate its pro-
tection circuitry and result in inefficient operation. The
effects of this problem are similar to the effects of the RF
problem described in Section 3.3.4. To prevent high-
frequency oscillations:
1. Lace together the loudspeaker conductors for
each channel; do not lace together the conduc-
tors from different channels. This minimizes the
chance that cables will act like antennas and
transmit or receive high frequencies that can
cause oscillation.
4-ohm, 20-watt
Resistor
590 to 708 µF Capacitor
120 VAC, N.P.
+
–
Inductive
Load
+
–
From
Amplifier
Output

Macro-Tech 3600VZ Power Amplifier
Page 19
Reference Manual
3.3.6 Additional Load Protection
Because the amplifier generates enormous power, it
may be desirable to protect loudspeakers (or other sen-
sitive loads) from damage due to excessive power. A
common way to do this is to put a fuse in series with the
load. This may be accomplished by using a single fuse
to protect the entire system, or by fusing each driver.
Fuses help prevent damage due to prolonged overload,
but provide essentially no protection against damage
from large transients. To minimize this latter problem,
use high-speed instrument fuses such as the Littlefuse
361000 series. If the loudspeaker is only susceptible to
damage caused by prolonged overload (such as over-
heating), use a fuse or circuit breaker having the same
slow thermal response as the loudspeaker itself (such
as a slow-blow fuse).
The nomograph in Figure 3.15 shows fuse size versus
loudspeaker peak power rating. It can be used to deter-
mine the size of the required fuse.
3.3.7 AC Power Requirements
Use an isolated power receptacle whenever possible
with adequate current. North American units are
shipped with a 30 amp (10 AWG) line cord, a NEMA
TT30P plug and a NEMA TT30R receptacle. Interna-
tional units are shipped without a plug connected to the
appropriate line cord. Line voltages of 10% or more
above the specified voltage may damage the amplifier.
Fig. 3.15 Loudspeaker Fuse Nomograph

Macro-Tech 3600VZ Power Amplifier
Page 20 Reference Manual
4 Operation
4.1 Precautions
Although the Macro-Tech 3600VZ is protected from ex-
ternal faults, the following precautions should be fol-
lowed for safety and optimum operation:
1. There are important differences among the Ste-
reo, Bridge-Mono and Parallel-Mono operating
modes (see Section 3.3).
2. WARNING: Do not change the position of the
Stereo/Mono switch unless the amplifier is
first turned off.
3. CAUTION: In Parallel-Mono mode, a jumper is
used between the Channel 1 and Channel 2
red binding posts (amplifier outputs). Be sure
to remove this jumper for Bridge-Mono or
Stereo mode; otherwise inefficient operation,
high distortion and excessive heating will oc-
cur. Check the Stereo/Mono switch on the
back panel for proper position.
4. Turn the amplifier off and unplug it from the
AC mains before removing a PIP card.
5. Use care when making connections, selecting
signal sources and controlling the output level.
The load you save may be your own.
6. Do not short the ground lead of an output cable
to the input signal ground. This may form a
ground loop and cause oscillations.
7. Operate the amplifier from AC mains of not more
than 10% variation above or below the selected
line voltage and only the specified line fre-
quency.
8. Never connect the output to a power supply
output, battery or power main.
9. Tampering in the circuit by unqualified person-
nel, or making unauthorized circuit changes may
be extremely dangerous and may invalidate the
warranty.
Remember: Crown is not liable for damage that results
from overdriving components in your system.
4.2 Indicators
The front panel has several helpful LED (light emitting
diode) indicators.
The amber Enable indicator is provided to show the
amplifier has been turned on (or enabled) and that the
low-voltage power supply is working. It does not indi-
cate the high voltage supply status. As a result, disrup-
tion of the high voltage supplies has no effect on the
Enable indicator. This means that in the improbable
event that one or both channels overheat and cause a
shut down of the high voltage power supply, the Enable
indicator will remain on. However, the Signal/ IOC indi-
cator lights to show that the output waveform does not
match the input.
The ODEP indicators provide a visual indication of the
operation of Crown’s patented Output Device Emula-
tion Protection ( ODEP ) circuitry. This circuitry protects
the amplifier output stages against heat damage by pro-
portionally limiting the drive level to the output stages.
This enables the amplifier to operate safely even under
severe operating conditions.
During normal operation, the ODEP indicators glow
brightly to indicate that the output stages are operating
within their thermal range (SOA - Safe Operating Area).
However, if an output stage begins to overheat, the
ODEP circuitry proportionally limits the drive signal and
the LEDs dim. In the unlikely event that the amplifier
exceeds the operating limits, ODEP shuts down the out-
put stages and the indicators turn off. The indicators
also turn off if the power supplies are put in standby
mode.
Note: The high voltage power supplies will temporarily
go into standby mode if their transformers get too hot or
if there is DC or heavy common-mode current in the
output.
The green Signal/ IOC indicators provide the triple
functions of Signal Presence, Distortion, and Input Over-
load indicators. As signal presence indicators, they
flash with normal intensity in sync with the audio out-
puts. 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%. Be-
cause transient distortion happens quickly, a 0.1 sec-
ond “hold delay” keeps the indicators on long enough
to be easily noticed. This IOC function verifies the
Fig. 4.1 Indicators