Protech 808B User Manual
PROTECH
MODELS COVERED
®
1/02
MICROPHONE PREAMPLIFIER & LINE AMPLIFIERS
INSTALLATION & OPERATION MANUAL
INTEGRA III SYSTEM
800 SERIES
806B
807B
808B*
*Microphone Preamplifier
www.protechaudio.com
The 800 Series Microphone Preamplifiers and Line Amplifiers are designed for use in professional audio
appplications. Each model has either one or two
channels, designed to operate as a discrete microphone
preamplifier or line amplifier. Dual channel cards will have
two identical channels constructed on one printed circuit
board.
Typical applications are public address systems,
broadcast studios, sales presentation rooms headphone listening systems, multi-room audio systems,
and recording systems. The actual application of the
amplifiers is found in buildings such as airports,
factories, courthouses, casinos, convention centers,
libraries, hotels, racetracks, training systems, corporate
boardrooms, etc...
The 800 Series Microphone Preamplifiers come in
two different models. There is a single channel, model
808B, and dual channel, model 816B. Both models
have low impedance transformer isolated inputs, and
a push-on red jumper, per channel, to enable 15 volt
phantom power. The gain of each channel is adjustable,
from 17 to 52dB.
The output section is balanced, transformer isolated.
814B
815B
816B*
Model 816B Shown
The 800 Series Line Amplifiers offer 4 different models, 2
single channel versions, and 2 dual channel versions.
The input section of the line amplifiers is available in two
different impedances. These are; bridging balancedtransformer isolated (10K ohm input impedance), and 600
ohm balanced-transformer isolated. This allows the user
to match the line amplifiers t o a variety of professional
audio equipment.
The trimpots used to adjust the gain levels of the microphone preamplifiers and line amplifiers are mounted
on the accompanying backplane assembly. This feature
allows the system gain settings to remain adjusted, even
when a line amplifier is removed from it's slot, and a
spare unit is plugged into that slot.
The output section of the line amplifiers is balanced
transformer isolated. On page 3 of this manual, you
will find a table showing the model numbers, and features
of each of the microphone preamplifiers, and the line
amplifiers.
Each of these products is designed to provide the user
with high quality audio, for years of uninterrupted
service.
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 800 Series Preamplifiers and Line Amplifiers are
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, Model 66708.
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 buss the DC power to the individual
card slots, and provide screw-type barrier termination points for
audio and DC connections.
After receiving an order for 800 audio cards, and prior to
shipping the order, the factory has requested from you or
your firm, a card file layout sketch. Using this drawing, the
factory has mounted the necessary trimpots in the backplane
assembly. This service allows the factory to test each card
in the card frame assembly, and saves the installer time when
assembling the complete audio system. Also, the installer can
be confident that each card received has been tested in the
actual slot used.
The actual steps necessary for installation of the 800 Series
Microphone Preamplifier and Line Amplifier cards, are comparable to those necessary for any of the 800 series 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.
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
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.
ALIGNMENT
Each 800 Series card with microphone level inputs has been
shipped from the factory aligned for 45dB of gain. Each Line
amplifier card has been shipped with the gain set for unity.
This alignment optimizes headroom. If additional gain is
required, the following alignment procedure is recommended;
1 - Apply a signal representative of the actual signal level to be
be used, to channel #1.
2 - While monitoring the ouput channel, turn the output gain
gain trimpot clockwise until the output signal reaches the
desired level. .
3 - Repeat steps 1 and 2 for each channel on your
preamplifier or line amplifier.
This completes the installation and alignment of your 800 Series
Limiter/Preamplifiers and Line Amplifiers. The cards may be
expected to deliver years of uninterrupted service.
Note 1The alignment procedures for 800 Series 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.
PROTECH
Channel #1 Gain
Channel #2 Gain
®
857B & 858B BACKPLANE
CONNECTIONS
H
L
H
L
INTEGRA III SYSTEM
CONNECTOR & TRIMPOT DRAWING
MODELS 806B Through 816B
INPUT #1 HI
INPUT #1 LO
GROUND
OUTPUT #1 HI
OUTPUT #1 LO
1
2
3
4
5
6
7
GROUND
8
9
10
H
L
H
L
INPUT #2 HI
INPUT #2 LO
GROUND
OUTPUT #2 HI
OUTPUT #2 LO
11
12
13
14
15
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, turn it on, and check for
proper illumination of the positive and negative voltage LED's,
on the front of the power supply card.
3- Terminate all audio input and output connections, using
the card connection drawing on page 3. Double conductor
shielded cable is recommended for all audio connections.
Terminate each unused input with a 1K ohm resistor.
Page 2
Model
Number
806B
807B
808B
814B
815B
816B
Channels
1
1
1
2
2
2
600 Ohm
Transformer
Input
*
*
10K Ohm
Transformer
Input
*
*
150 Ohm
Transformer
Input
*
*
17-52dB
Gain
*
*
-10 To
25dB
Gain
*
*
*
*
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