Crown Com-Tech CT-1610 User manual

Com-Tech 810 and 1610 Amplifier Service Manual
]
Rev. 0
KSVCCT810/1610
8/98
Commercial Audio
E106377
®
120 VAC North
American Units:
© 1998 by Crown International, Inc., P.O. Box 1000, Elkhart, Indiana 46515-1000 U.S.A. Telephone:
219-294-8000. Com-Tech amplifiers are produced by the Professional Audio Division of Crown
International, Inc. Trademark Notice:
SmartAmp
™and
Grounded Bridge
™are trademarks and
Amcron ,
®
Crown ,
®
Com-Tech ,
®
IOC ,
®
ODEP ,
®
IQ System ,
®
P.I.P.
®and
TEF
®are registered trademarks of Crown
International, Inc. Other trademarks are the property of their respective owners.
Models:
Com-Tech 810 & 1610
Some models may be exported under the name Amcron.
®
COM-TECH®
®
For
Canada
Service Manual
[

Com-Tech 810 and 1610 Amplifier Service Manual
]
Rev. 0
À PRÉVENIR LE CHOC
ÉLECTRIQUE N’ENLEVEZ
PAS LES COUVERTURES.
RIEN DES PARTIES
UTILES À L’INTÉRIEUR.
DÉBRANCHER LA BORNE
AVANT D’OUVRIR LA
MODULE EN ARRIÈRE.
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 BEFORE REMOVING
REAR INPUT MODULE TO ACCESS
GAIN SWITCH.
CAUTION AVIS
WARNING
TO REDUCE THE RISK OF ELECTRIC
SHOCK, DO NOT EXPOSE THIS
EQUIPMENT TO RAIN OR MOISTURE!
The information furnished in this manual does not include all of the details of design, production, or variations of
the equipment. Nor does it cover every possible situation which may arise during installation, operation or
maintenance. If you need special assistance beyond the scope of this manual, please contact the Crown Tech-
nical Support Group.
Mail: P.O. Box 1000, Elkhart IN 46515-1000
Shipping: Plant 2 SW, 1718 W. Mishawaka Rd., Elkhart, IN 46517
Phone: [phone]
FAX: [phone]
I

Com-Tech 810 and 1610 Amplifier Service Manual
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Table of Contents
1 Introduction .............................................................................. 1-1
1.1 The Com-Tech Series ....................................................... 1-1
1.2 Warranty ........................................................................... 1-1
2 Specifications .......................................................................... 2-1
2.1 Performance ..................................................................... 2-1
2.2 Power ............................................................................... 2-1
2.3 Controls............................................................................ 2-1
2.4 Indicators ......................................................................... 2-2
2.5 Input/Output ..................................................................... 2-2
2.6 Output Signal ................................................................... 2-2
2.7 Protection ......................................................................... 2-2
2.8 Construction ..................................................................... 2-2
3 AC Power Draw and Thermal Dissipation ................................ 3-1
4 AC Mains Voltage Conversion ................................................. 4-1
4.1 Com-Tech Voltage Conversion ........................................ 4-1
4.1.1 120 VAC, 60 Hz Units .............................................. 4-1
4.1.2 100/120 VAC Export Units ....................................... 4-1
4.1.3 220/240 VAC Export Units ....................................... 4-1
5 Theory ...................................................................................... 5-1
5.1 Overview .......................................................................... 5-1
5.2 Front End Operation ......................................................... 5-1
5.2.1 Balanced Gain Stage (BGS) .................................... 5-1
5.2.2 Variable Gain Stage (VGS) ...................................... 5-1
5.2.3 Error Amp................................................................. 5-2
5.3 Voltage Amplification ....................................................... 5-2
5.3.1 Voltage Translators .................................................. 5-2
5.3.2 Last Voltage Amplifiers (LVAs) ................................. 5-2
5.4 Grounded Bridge Topology ............................................. 5-3
5.4.1 High Side (HS)......................................................... 5-3
5.4.2 Low Side (LS) .......................................................... 5-4
5.5 Output Device Emulation Protection (ODEP) ................... 5-4

Com-Tech 810 and 1610 Amplifier Service Manual
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5.6 Dual Operation................................................................. 5-6
5.7 Bridge-Mono Operation ................................................... 5-6
5.8 Parallel-Mono Operation .................................................. 5-6
6 Electrical Checkout Procedures .............................................. 6-1
6.1 General Information .......................................................... 6-1
6.2 Test Procedures ............................................................... 6-1
6.2.1 Standard Initial Conditions ...................................... 6-1
6.2.2 Turn On Delay .......................................................... 6-1
6.2.3 Output Bias Adjustment ........................................... 6-1
6.2.4 ODEP Voltage Adjustment ....................................... 6-1
6.2.5 DC Offset ................................................................. 6-1
6.2.6 Quiescent Power Draw ............................................ 6-2
6.2.7 Voltage Gain ............................................................ 6-2
6.2.8 Current Sense Calibration ....................................... 6-2
6.2.9 Common Mode Rejection ........................................ 6-2
6.2.10 Current Limit .......................................................... 6-2
6.2.11 10 kHz Square Wave Response ............................ 6-2
6.2.12 20 kHz Crosstalk.................................................... 6-3
6.2.13 Output Power ......................................................... 6-3
6.2.14 ODEP Limiting ....................................................... 6-3
6.2.15 Fan Operation (optional in Com-Tech 210) ............ 6-3
6.2.16 LF Protection .......................................................... 6-4
6.2.17 Signal to Noise ...................................................... 6-4
6.2.18 Intermodulation Distortion (IMD) ............................ 6-4
6.2.19 Displays................................................................. 6-4
6.2.20 Auto Standby Operation ........................................ 6-4
6.2.21 Post Testing ........................................................... 6-4
7 Exploded Views ....................................................................... 7-1
8 Schematics and Module Documentation ................................. 8-1

Com-Tech 810 and 1610 Amplifier Service Manual
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Crown International, Inc.
Mailing : PO Box 1000
Elkhart, IN 46515-1000
or
Shipping : Plant 2 S.W.
1718 W. Mishawaka Rd.
Elkhart, IN 46517
Toll Free: [phone]
Phone: [phone]
FAX: [phone]
Web: www.crownaudio.com
This manual contains service information for the Crown
Com-Tech–10 Series power amplifiers. It is designed
to be used in conjunction with the Com-Tech Refer-
ence Manual. Some important information is, however,
duplicated in this Service Manual in case the Refer-
ence Manual is not readily available.
NOTE: THE INFORMATION IN THIS MANUAL IS IN-
TENDED FOR USE BY AN EXPERIENCED TECHNI-
CIAN ONLY!
1.1 The Com-Tech Series
The Com-Tech series is a complete family of amplifiers
with a wide range of power output capabilities. Com-
Tech amplifiers can directly drive "constant voltage"
lines, so you can avoid the expense, distortion and
insertion loss associated with step-up transformers for
distributed loudspeaker systems. Com-Tech amplifi-
ers also utilize Crown's patented ODEP
®
protection cir-
cuitry, which keeps the amplifier working under severe
conditions that would shut down a lesser amplifier. All
Com-Tech amplifiers feature Crown's exclusive P.I.P.
®
(Programmable Input Processor) expansion system.
The P.I.P. expansion system makes it easy to tailor
your amplifier to a specific application or to add future
technology as it develops.
1.2 Warranty
Each Reference Manual contains basic policies as re-
lated to the customer. For further assistance please
contact the Crown Technical Support Group at:
1 Introduction
Figure 1.1 Com-Tech 810 and 1610 front panels
ODEP
IOC
SPI
CH1 CH2
LOCAL
OFF
REMOTE
ODEP
IOC
SPI
CH1 CH2
LOCAL
OFF
REMOTE

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The following specifications apply to all models in Dual mode
with 8-ohm loads and an input sensitivity of 26 dB unless
otherwise specified.
MAP at 1 kHz: This term refers to maximum average power in
watts at 1 kHz with 0.1% THD.
Full Bandwidth Power: This term refers to maximum average
power in watts from 20 Hz to 20 kHz with 0.1% THD.
120 VAC, 60 Hz Units: These North American units have dedi-
cated transformers for 120 VAC, 60 Hz power mains.
100/120 VAC Units: These units have two-tap transformers
that accept a 50- or 60-Hz AC line, and can be configured
for 100 or 120 VAC mains.
220/240 VAC Units: These units have two-tap transformers
that accept a 50- or 60-Hz AC line, and can be configured
for 220 or 240 VAC mains.
2.1 Performance
Frequency Response: ±0.1 dB from 20 Hz to 20 kHz at 1
Watt (See Figure 2.1).
Phase Response: ±10 degrees from 10 Hz to 20 kHz at 1
Watt (See Figure 2.4).
Hum and Noise: A-weighted, 105 dB below full bandwidth
power; No weighting, 100 dB below full bandwidth power.
Total Harmonic Distortion (THD): Less than 0.05% at full power
from 20 Hz to 1 kHz increasing linearly to 0.1% at 20 kHz.
Intermodulation Distortion (IMD): (60 Hz and 7 kHz 4:1) Less
than 0.05% from -35 dB to full power bandwidth.
Damping Factor: Greater than 1000 from 10 Hz to 400 Hz
(See Figure 2.2).
Crosstalk: Greater than 70 dB down at 10 kHz. (See Figure
2.5).
Common Mode Rejection Ration (CMRR): Better than 70 dB.
Slew Rate: Greater than 17 volts per microsecond.
Voltage Gain: (At the maximum level setting) 20:1 ±3% or 26
dB ±0.25 dB. 90:1 ±12% or 39 dB ±1 dB with the input
sensitivity set to 0.775 volts for 70 volt output. The following
voltage gain specifications are for units with the input sensi-
tivity set to 0.775 volts for 8/4 ohm output:
Com-Tech 810: 64:1 ±12% or 36 dB ±1 dB.
Com-Tech 1610 : 85:1 ±12% or 39 dB ±1 dB.
2.2 Power
Output Power: See the minimum Guaranteed Power table in
Figures 2.6-7 for the output power specifications under a
variety of conditions.
It is extremely important to supply the amplifier with ad-
equate AC power. Power amplifiers cannot add power–they
need the required voltage and current to deliver the
undistorted rated wattages you expect.
Load Impedance: Safe with all types of loads. With 8/4 ohm
output, all Com-Techs are rated for 4 to 8 ohms in Dual
mode, 8 to 16 ohms in Bridge-Mono mode, and 2 to 4 ohms
in Parallel-Mono mode. With a 70 volt output, rated loads
vary among the different models for each dual/mono mode
(see the power matrices that follow).
AC Power Requirements: All units require less than 90 watts
at idle. See Section 3 for detailed information on AC power
requirements and thermal dissipation.
Low-Voltage Power Supply: ±15 VDC regulated supplies are
provided by a winding on the power transformer.
Power Cord: An appropriate AC line cord is provided with a
nominal cable length of 3 feet.
2.3 Controls
Enable: A front panel rocker switch used to turn the amplifier
on and off, and to enable the remote feature.
Input Attenuation: A detented 21-position back panel Input
Attenuation control for each channel.
Output Mode: A back panel switch for each channel used to
select 8/4-ohm or 70-volt output.
Dual/Mono: A 3-position back panel switch used to select
Dual, Bridge-Mono or Parallel-Mono operation.
Reset: A back panel push button used to reset the amplifier's
AC mains breaker.
Input Sensitivity: A three-position switch inside the P.I.P. com-
partment used to select an input sensitivity for both chan-
nels: 0.775 volts for MAP at 1 kHz in 8/4 ohm mode, 0.775
volts for MAP at 1 kHz in 70-volt mode, or a voltage gain of
26 dB.
2 Specifications

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2.4 Indicators
Enable: This amber indicator shows the on/off status of the
unit's low-voltage power supply and the activation of the
energy-saving mode.
SPI (Signal Presence Indicator): Each channel has a green
indicator that flashes to show audio output.
IOC (Input/Output Comparator): Each channel has a yellow
indicator that flashes if the output waveform differs from the
input waveform by 0.05% or more. The LEDs act as sensi-
tive distortion indicators to provide proof of distortion-free
performance.
ODEP (Output Device Emulation Protection): Each channel has
a green multifunction indicator that shows the channel's re-
serve energy status. Normally, the LEDs are brightly lit to
show that reserve energy is available. In the rare event that
a channel has no reserve, its indicator will dim in proportion
to ODEP limiting.
2.5 Input/Output
Input Connector: A barrier block on the standard PIP2-BB
with three-terminal balanced connections for input to each
channel and test points for a DVM.
Input Impedance: Nominally 20 K ohms, balanced. Nomi-
nally 10 K ohms, unbalanced.
Input Sensitivity: Settings include 0.775 volts for 8/4-ohm
output, 0.775 volts for 70-volt output, and a voltage gain of
26 dB.
Output Connector: A back panel barrier block with two-termi-
nal connections for each output channel.
Output Impedance: Less than 10 milliohms in series with less
than 2 microhenries (see Figure 2.3).
DC Output Offset: Less than ±10 millivolts.
RSVP: An RJ11 modular connector on the back panel inter-
faces with an RSVP to provide remote control of amplifier
power on/off functions.
2.6 Output Signal
Dual:Unbalanced,two-channel.
Bridge-Mono: Balanced, single-channel. Channel 1 controls
areactive;Channel 2shouldbe turneddown.Channel 1red
terminal is positive, referenced to ground, when the input is
positive.
Parallel-Mono:Unbalanced,single-channel.Channel1con-
trols are active; Channel 2 is bypassed.
2.7 Protection
Com-Tech amplifiersareprotectedagainstshorted,openor
mismatched loads; overloaded power supplies; excessive
temperature,chaindestructionphenomena,input overload
damage and high-frequency blowups. It also protects
loudspeakers from input/output DC and turn-on/turn-off
transients.
If unreasonable operating conditions occur, the patented
ODEP circuitry proportionally limits the drive level to protect
the output devices, particularly in the case of elevated
temperature.Transformeroverheatingresultsinatemporary
shutdown of both channels. The transformer automatically
resets itself when it has cooled to a safe temperature.
Controlledbyslewrate,voltageamplifiersprotectagainstRF
burnouts, and input overload protection is provided by
current-limiting resistance at the input.
Turn On: The four-second turn on delay prevents dangerous
turn-ontransients.“Soft-start”circuitryprovideslowinrushso
power sequencers are rarely needed with multiple units.
Note: The turn-on delay time may be changed. Contact
Crown's Technical Support Group for details.
Circuit Breaker: Circuit breaker current ratings vary based on
the Com-Tech model and AC mains voltage.
All 100/120 VAC Units:
Com-Tech810 :20 amperes.
Com-Tech1610 :30amperes.
All 220/240 VAC Units:
Com-Tech810 :10 amperes.
Com-Tech1610 :20amperes.
2.8 Construction
Durable black powdercoat finish on the steel chassis, front
panel Lexan overlay, and specially-designed flow-through
ventilation from front to side panels.
Cooling:Internal heat exchangers with on-demand forced
air cooling (fan is optional for the North American Com-
Tech 210 ).
Dimensions: 19 inch (48.3 cm) standard rack mount width
(EIA RS-310-B), 16 inch (40.6 cm) depth behind mounting
surface,and0.25inches(0.6cm)infrontofmountingsurface.
Amplifierheight variesamongtheavailablemodels andwith
different AC power requirements (see Figure 2.10).
Height A: 3.5 inches (8.9 cm)
Models: Com-Tech 210 (All)
Com-Tech 410 (North American)

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Height B: 5.25 inches (13.3 cm)
Models: Com-Tech 410 (100/120 VAC, 50/60 Hz)
Com-Tech 410 (220/240 VAC, 50/60 Hz)
Com-Tech 810 (All)
Height C: 7 inches (17.8 cm)
Model: Com-Tech 1610 (All)
Approximate Weight: Center of gravity is 6 inches (15.2
cm) behind the front mounting surface.
120 VAC, 60 Hz North American Units:
Com-Tech 810 : 47 pounds, 4 ounces
(21.5 kg) net; 50 pounds, 8 ounces
(22.9 kg) shipping weight.
Com-Tech1610 :57 pounds, 14 ounces
(26.3 kg) net; 66 pounds, 10 ounces
(30.2 kg) shipping weight.
100/120 VAC, 50/60 Hz Units:
Com-Tech 810 : 45 pounds, 1 ounce
(20.5 kg) net; 49 pounds, 10 ounces
(22.5 kg) shipping weight.
Com-Tech1610 :54 pounds, 11 ounces
(24.8 kg) net; 64 pounds, 3 ounces
(29.1 kg) shipping weight.
220-240 VAC, 50/60 Hz Units:
Com-Tech 810 : 45 pounds, 4 ounces
(20.5 kg) net; 49 pounds, 13 ounces
(22.6 kg) shipping weight.
Com-Tech 1610 : 55 pounds, 2 ounces
(25.0 kg) net; 64 pounds, 10 ounces
(29.3 kg) shipping weight.
C: 7 in
(17.8 cm)
OFF
ODEP
IOC
SPI
CH1CH2
B: 5.25 in
(13.3 cm)
A: 3.5 in
(8.9 cm)
19 in
(48.3 cm)
16in
(40.6cm)
LOCAL
REMOTE
Figure 2.10 Mounting Dimensions

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10 100 1 K 10 K 100 K
FREQUENCY (Hz)
+2
+1
0
–1
–2
–3
–4
dB
–5
–6
–7
4 ohm
8 ohm
1 watt
504.0
126.8
31.8
MILLIOHMS
8.0
2.0
6 dB
20 100 1 K 10 K 20 K
400
200
100
0
600
800
1000
1200
1400
FREQUENCY (Hz)
8 ohm
10 100 1 K 10 K 100 K
FREQUENCY (Hz)
Figure 2.1 Typical Frequency Response
Figure 2.2 Typical Damping Factor
Figure 2.3 Typical Output Impedance