MODEL 882
FREQUENCY ADJUSTMENT
LINE AMPLIFIER/TONE CONTROL
FREQUENCY LOW FREQUENCY HIGH FREQUENCY
CHART
PROTECH
®
1/06
INSTALLATION & OPERATION
MANUAL
LINE AMP/TONE CONTROL CARD
20 Hz
30 Hz
40 Hz
50 Hz
60 Hz
80 Hz
100 Hz
150 Hz
200 Hz
300 Hz
400 Hz
500 Hz
600 Hz
700 Hz
800 Hz
CUT (dB) BOOST (dB)
Full CCW Full CW
-16.25
-15.75
-15.00
-14.50
-14.00
-12.75
-11.50
-9.50
-7.50
-4.75
-3.00
-1.90
-1.25
-0.75
-0.50
+16.25
+15.25
+14.75
+14.25
+13.50
+12.50
+11.75
+9.50
+7.50
+4.75
+3.00
+2.00
+1.50
+0.90
+0.40
CUT BOOST
Full CCW Full CW
-0.75
+1.50
MODELS COVERED
882
INTEGRA III SYSTEM
Model 882 Shown
www.protechaudio.com
900 Hz
1 KHz
2 KHz
4 KHz
6 KHz
8 KHz
10 Khz
12 KHz
14 KHz
16 KHz
18 KHz
20 KHz
-0.25
0.00
+0.25
0.00
-2.00
-5.00
-9.00
-10.50
-11.75
-12.00
-12.50
-13.00
-13.25
-13.75
-14.00
NOTE: Gain at Unity.
Gain settings made with pots at flat position, and 1KHz as reference frequency.
+2.00
+4.50
+8.25
+10.00
+10.75
+11.25
+11.50
+11.50
+11.50
+11.50
+11.50
The Model 882 Line Amplifier/Tone Control card is
designed for frequency response shaping in professional
audio systems.
Typical applications are public address systems, broadcast
studios, sound reinforcement systems, headphone listening
systems, room combining systems, and recording systems.
The actual application of the line amp/tone control card is
found in such buildings as airports, factories, courthouses,
casinos, convention centers, hotels, racetracks, training systems, corporate boardrooms, etc.,.
The input section of the Model 882 is balanced, transformer
isolated, using a high quality bridging type line transformer.
The transformer is followed by an op-amp input buffer stage.
The gain of the input stage is fixed, at unity, in order to prevent
overdriving of the frequency shaping section.
The frequency shaping section provides a low frequency
adjustment capable of 12dB of cut and boost, and a high
frequency adjustment, also capable of 12dB of cut and boost.
Both sections are adjusted via separate trimpots, accessible
from the front of the plug-in card. The characteristics of the
frequency shaping circuit are classified as shelving type, and
centered at 1KHz.
The frequency shaping section is followed by a buffer amplifier,
to prevent changes in frequency response settings from
occuring, when the output load changes.
The output section consists of a low noise op-amp, with
adjustable gain, followed by a high quality output transformer.
The gain of the output section is adjustable via a trimpot
mounted on the backplane assembly. Adjustment of the gain
will have no effect on the low frequency or high frequency
settings.
The Model 882 may be mixed or matched or matched with other
INTEGRA III SYSTEM components, within the same card
frame, without degradation in performance. The Model 858B
Card Frame Package is a self powered card farme with 9 slots
available for audio cards. The Model 857B Card Frame Package
is a 10 slot card frame assembly intended for use with an external
power supply. Both card frame packages require just 3.5 inches
of vertical rack space.
The Model 882 Line Amplifier/Tone Control Card may be
expected to provide the user with years of dependable, uninterrupted quality service. For additional information, ordesign
assistance, contact:
APPLICATIONS ASSISTANCE
Protech Audio Corporation, PO Box 597, 192 Cedar River Road, Indian Lake, New York, 12842, Voice 518-648-6410 Fax 518-648-6395
INSTALLATION
The 882 Line Amplifier/Tone Control Card is designed to
be mounted in the Model 857B Card Frame Package, or
the Model 858B Card Frame Package. The Model 857B Card
Frame Package will accomodate up to 10 audio cards, and
requires an external power supply. The Model 858B Card Frame
Package will accomodate up to 9 audio cards, and has a built-in,
unpluggable power supply card.
Both card frame assemblies bus the DC power to the individual
card slots, and provide screw-type barrier termination points for
audio and DC connections.
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.
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
and turn on the power supply. Make sure no unusual loading is
noticed 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.
half-way into the card frame, plug in one card at a time
ALIGNMENT
Each INTEGRA III SYSTEM card with line level inputs has been
shipped from the factory aligned for unity gain. This alignment
optimizes headroom. Ifadditional gain is required, the following
alignment procedure is recommended;
PROTECH AUDIO
857B & 858B BACKPLANE CONNECTIONS
GAIN
®
CONNECTOR & TRIMPOT DRAWING
INPUT LO
INPUT HI
GND
OUTPUT HI
OUTPUT LO
INTEGRA III SYSTEM
MODEL 882
1
2
3
4
5
The actual steps necessary for installation of the Model 882
Line Amplifier/Tone Control 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 tensile 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.
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 panel.
1 - Apply a signal representative of the actual signal level to
be used, to the input.
2 - While monitoring the #1 output channel, turn the output
gain trimpot clockwise until the output signal reaches
the desired level.
3 - Using whatever measuring system is appropriate for the
particular installation, adjust the low frequency trimpot
until the desired low frequency response is achieved.
4 - Repeat step 3, now adjusting the high frequency trimpot.
This completes the installation and alignment of your Line
Amplifier/Tone Control cards. The cards may be expected to
deliver years of uninterrupted service.
Note 1 The alignment procedures for INTEGRA III SYSTEM cards,
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 different card
types.
HI FREQUENCY
LOW FREQUENCY
GND
GND
CW = BOOST,
HORIZONTAL = FLAT
6
7
8
9
10
11
12
13
14
15
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. Terminate each unused input with a 1K ohm
resistor.
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CCW = CUT
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