Protech 861A User Manual
PROTECH
MODELS COVERED
861A
883A
884A
12/03
®
10 Watt Audio Power Amplifier Cards
INSTALLATION & OPERATION MANUAL
INTEGRA III SYSTEM
INTEGRA III SYSTEM
Model 883A Shown
www.protechaudio.com
The Integra III System 10 Watt Audio Power
Amplifier Cards are designed for use in continuous
duty professional applications.
All 6 units are designed to drive 4 or 8 ohm loads to
a maximum of 10 watts RMS. Each model incorporates a combination of features that will allow the
unit to deliver maximum performance and reliability. Each circuit is designed with a minimum of
components, to reduce the possibility of failure,
while still maintaining performance and feature
criteria. Only the highest quality components are
used in the construction of these audio power
amplifiers. These units are designed to be used in
systems that operate 24 hours a day, 7 days a
week.
Typical applications are legilsative venues,
boardrooms, council chambers, judicial systems,
sales presentation rooms, headphone listening systems, public address systems, multi-room audio
systems, and recording systems. The actual
application of the amplifiers is found in buildings
such as public buildings, courthouses, legislative or council buildings, convention centers,
factories, libraries, hotels, racetracks, training
systems, corporate boardrooms, etc.,.
The Model 861A has a bridging, unbalanced
input. The gain trimpot is mounted on the rear of
the card frame. This rear mounting location
serves two purposes. The rear mounted trimpots
prevent tampering with the gain settings, and, if
a spare unit should be put into service, no realignment of the gain setting is necessary. Both
desirable features when semi-technical personnel may be called upon to maintain the system.
The model 883A has a balanced, transformerisolated bridging type input.
The model 884A has a 600 ohm transformer
isolated input.
All three models offer a mute function, that is
activated by grounding the mute control pin.
The specifictions on all 3 units make them ideal
for high quality audio systems. And the card file
format allows up to 10 amplifier circuits to be
mounted in just 3.5" of vertical rack space.
These products are designed to provide the user
with high quality audio, for years of uninterrupted service.
Protech Audio Corp., 192 Cedar River Road, Indian Lake, New York 12842 Voice 518-648-6410 Fax 518-648-6395
INSTALLATION
The Audio Power Amplifier cards are designed to be
mounted in the Models 857B or 858B Card Frame Assemblies. The Model 857B will accomodate up to 10 amplifier
cards, using an external power supply, and the Model
858B will accomodate or up to 9 audio cards, and uses
a plug-in power supply card. The Audio Power Amplifier
Cards require 480ma of DC current, in order to deliver 10
watts of audio power. The power supply card used in the
Model 858B card frame assembly is designed to deliver
600ma of power to a card frame. Therefore it is
recommended that systems using these power
amplifier cards have an external power supply configuration. (Model 857B and Power Supply Model 66708). The
Model 858B may be used in systems where the power
amplifier cards will be used to provide only 1 or 2 watts of
audio power.
The backplane assemblies come in two versions.
Model 857B- is designed for use with 10 audio cards.
Model 858B- is designed for use with 9 audio cards, and
one plug-in power supply card.
The determination as to which card frame assembly to use
in your project, was made prior to our factory receiving the
order. The card frame assembly you have received
will accommodate the group of cards you or your designer
have specified.
The actual steps necessary for installation of the Power
Amplifier cards, are comparable to those necessary for
any of the Integra III System cards. They are as follows;
1- Mount the card frame in an appropriate EIA 19" width
rack, using 4 screws of sufficient strength to provide
secure mounting.
2- A determination has been made as to which type of
power supply will be used on your system. Follow the
instructions for the type of power supply you will be
installing.
EXTERNAL POWER SUPPLY. If an external power
supply is to be used, terminate the proper supply
connections to pins 1, 2, & 3 of the DC barrier connector,
as shown in the card frame layout drawing. Turn on the
power supply, and using a DC voltmeter, check for
correct voltage and polarity at pins 1, 2, & 3 of the barrier
connector.
3- Terminate all audio input and output connections, using
the card connection drawing on the facing page. Double
conductor shielded cable is recommended for all audio
connections. Output connections should be made using
#18AWG wire or heavier.
4- Unpack each individual card, inspect for shipping
damage, and assuming none is found, slide the
card
half-way into the appropriate slot. After all cards have
been installed half-way into the card frame, plug in one
card at a time and turn on the power supply. Make sure no
unusual loading is indicated at the power supply . If
loading is noticed, turn off the power supply, unplug the
card and recheck terminations. If no loading is noticed,
continue inserting each card in the card frame, checking
power supply loading as each card is plugged in. When all
the cards have been plugged in, the installation is
complete, and all that remains is the alignment.
ALIGNMENT
Each Power Amplifier card has been shipped from the
factory aligned for 7dB of gain. This alignment level helps
prevents damage to speakers upon initial system turnon. If additional gain is required, the following
alignment procedure is recommended;
1- Apply a signal representative of the actual signal level
to be used, to the input.
2- While monitoring the output channel, turn the output
gain trimpot, mounted on the backplane, clockwise, until
the output signal reaches the desired level.
3- Repeat step #2 for each Power Amplifier Card in your
system.
This completes the installation and alignment of your
Power Amplifier Cards. The Power Amplifiers may be
expected to deliver years of uninterrupted service.
Note #1The alignment procedures differ from card type to card
type. Therefore it is necessary to consult the alignment
procedure for each type of card being installed, to properly
align a card frame using fifferent card types.
PROTECH AUDIO
Models 857B, & 858B Backplane Connections
GAIN
®
H
L
EXTERNAL
CLOSURE
INTEGRA III SYSTEM
CONNECTOR & TRIMPOT DRAWING
MODELS 861A, 883A, 884A
INPUT HI
INPUT LO
SHIELD
OUTPUT HI
OUTPUT LO
MUTE
1
2
3
4
5
6
7
GROUND
8
9
10
11
12
13
14
15
INTERNAL POWER SUPPLY. If a plug-in power supply
card is to be used, plug in the supply card, and check for
proper illumination of both the positive and negative voltage LED's, on the power supply card front.
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