BEFORE
PLEASE
PROCEEDING WITH
COMPLETE
READ THE SECTION ON
OBL
UNPACKING
UNPACKING
UREI
ELECTRONIC
PRODUCTS
INSPECTION
AND
AND
SETUP
model
AUTOMATIC
JBL
8500
NORTHRIDGE, CA.
BALBOA
PHONE:
TELEX:
JBL
Ifetls^bMER
751
OB
MICROPHONE
Incorporated
BOULEVARD
2200
BOX
P.O.
91329
818
(
PROPEeSldNAL
893-8411
)
4720424
MIXER
USA
H .
1
©Copyright
1988,
JBL
8370
3^POA.BOULEVAFD
5-
NORTHRIOGE,
^RQNE
FAXtsisj 891-9619
Incorporated
m,
(818)
0
132,9.
893-8411
S
U.SJV;
A.
Manual
751
OB
Section One
.refac
J.JL...P
Thank
achieve optimum
and
read
on our products and
This manual is
our
products
Unpacking
1
.2
Your new
designed to protect the unit during shipment
shipping carton and
If
damage is
carrier
e
purchasing this JBIVUREI product We
for
you
make
to
dedicated
in
order
JBL/UREI
evident
of
possible
a
The shipping
The JBL/UREI
utility and
of the
use
performance
material contained in this manual. We welcome your suggestions and comments
on this manual.
all
to
to best use
Inspection
and
Automatic
its contents
not
do
claim
carton
destroy
for damage. Damage
should
Model
from
the people
them.
who
Learn, Enjoy
Microphone Mixer was carefully packed at the factory,
for
sign
any
any
contain:
7510B
of
Automatic
introdUCliOD
have prepared
new
your
are interested
Nevertheless,
of physical damage
packing material or
the
claims
Automatic
Share.
and
must
Microphone Mixer
Microphone Mixer.
in learning
this instruction manual
the capabilities and limitations
about
to
enable
We encourage
and the container was
we recommend careful examination of the
be
which
the
made
by you.
may
carton,
have
occurred in transit
and immediately notify
you to
you
the
to
of
Instruction Manual
This
An
envelope containing Rack Mounting Hardware
If
1.3 About
The
diagrams
connectors
Installation,
Note: In this manual, unless otherwise specified,
milliwatt in a
this_Mamjal
of
(derating
have purchased extra
you
and information on the following two pages provide an overview
Model
the
circuit with
lOB Automatic Microphone Mixer. Additional
75
Instructions, and
load impedance
a
7510-03
Theory
of 600 ohms.
Input Expander
of Operation
sections.
0 dBu is equivalent
Assemblies, they are separately
the
of
detailed information follows
to 0.775
volts and
controls, indicators and
0 dBm is one
packed.
in the
Page
1
1.4 Front Panel
Manual
751
OB
A. Input
Adjust
from
Gain Control
compensate
to
different talkers,
source-to-microphone
Release
B
Screwdriver adjust
before an
delay
Fastest
CW to
C.
release
avoid channel
Threshold
Screwdriver adjust
required to
signal
Priority modes.
or
with the
CCW
threshold
threshold is also
control which
control
reduce
to
level
trimpot. Adjusts the
active channel is turned
is full CCW. Turn
trimpoL Sets
turn ON
The
full CW.
set
die sensitivity
the channel. Note that
of
)
affected by the input
should
D. Channel On LED
for different
microphones
distances.
turn-off
most
between
input
the
sensitive position is
Turn
( increase the
be set
first for
volume
and
time
OFF.
the control
words.
level
the
in
Automatic
the control
gain
mix balance.
level
of
the
‘
*
*
•"
’
2
2
(
^
0
AUTO
8
)
y
^
10
wiiomTv
9
^
A
Turns
excellent tool
of threshold
E. Mode Switch
Select ON to
whenever the
on
for checking for marginal settings
and release controls.
defeat the Auto
channel will always be
Select
AUTO
A channel
threshold
the
Select
AUTO
inputs
one or two
Too
been
PRIORITY
mode,
which are in the AUTO mode may
many
placed
choose the
to
will
turn ON
level.
to
will simultaneously turn OFF all inputs
but
inputs
to be
PMORITY
in
the ON mode.
channel
live.
when its
choose
in PRIORITY mode.
active.
is
function.
Mix
Mix function.
Auto
input exceeds
Priority function. The channel
channels defeats
An
The
turn ON wMe
PRIORITY
this purpose.
Figure 1 The Front Panel-Input Section
will turn ON under the same conditions
which
PRIORITY
a
mode
PRIORITY
live
are
input is live. Do not select more than
allows
mode does
in
and
one input
not affect channels
the AUTOmode. No other
take control of the
to
as
which
in
mixer.
have
Page 2
F. Master Gain
Manual
751 OB
This
level tom
Background Threshold Control
G.
full CCW click
At
individual
an
threshold
position
threshold varies
from
normal
the
is
the Main
circuit of that
of the
all
the
of
“background”
turning
increases the
input
turn ON.
H. Output
0
I. Power LED
J. Voltage Test Point
level
VU is
ON
a
must
calibrated to
Master mix control. It
OuQ)ut
position the
channel
is
Background
according
microphones
level rises, so
channel. CW
amount
by
exceed the
Meter
+4
fixed,
individual
Threshold
to
rotation of the control
which
“background”
dBm at the
threshold
and is
the
in
does
set
channel.
control, the
amount of
the system. As
threshold
the
individual channel
an
Main
controls output
for turning ON
only by
before it
Output.
the
In any other
signal sensed
the
for
will
For adjustment
Section
See
K. RTI-Background Preset
Section
See
RT2-Background
L.
Section
See
of background preset voltage
2.4.4.
2.4.4.
Offset
2.4.4.
M. Power Switch
trimpot
trimpot.
.
and offset.
Figure
2
The
Front
Panel
-
Output
Section
Page
3
Manual
751 OB
Three pin XL
pin
output. The
controlled
A 10
may be
ground.
signal to
the
the
the ring
amplifier
The
inputs.
This is a
Master
is 2
“+”
is
3
by
input on
kohm
wired
An input
summing
a
NOM
number of
circuit.
contact
just
level does
low impedance output
Gain
kohm.
connector.
style
pin 2
and
signal
level
front
Ae
a
either of two
wired
amplifier
Level,
brings
not
inputs.
to
vary with
active
prior
control.
Pin 1
of the
side
is
connector
this
from
Master
panel
3-conductor
ways.
contact
tip
the
to
under
therefore,
An input
signal
the
Master
to
the
another
Gain
number
prior
Minimum load
ground,
is
floating
control.
Gain
phone jack
Shield
varies
is
returns
control
with
wired
summing
control.
of active
the
to
impedance
is
of
to
connector is
This
7510B
Turn the
Phantom
You
switch, and
Hz,
the
the
pin
15
mainframes.
switch ON to
Power to
can choose
grounded
"230"
position
cord
to a
connect
power source.
See
all inputs.
"115"
the
the
of
source,
the AC
power
240 VAC,
interconnecting two
for
Page 10
supply
+48 VDC
position of
cord
to a
or you
switch,
Hz,
50/60
120
grounded
the
VAC,
may
and
AC
60
choose
connect
Page
4
G. Input CoDPectof
Manual
751
OB
Thisisa
7510-03 Input
on
a
into the
tighten the
and
which
style
Assembly
12
holes
for
pin
may be
Page 6.
H. Direct
A
600
conductor
7510B
output
Direct Outputs
Remote
I.
gain
The
changed
connector
Adjust
activation of
logic
Output/Patch
nominal
ohm
phone
is on the
follows
Control
each of
of
replacing the
by
with resistors
on Page
circuitry.
connector
indicated
as
screws.
ease
jack, return
ring
the circuit
Page 9.
on
7.
input is also
any
See
which serves
by
Strip
the
Assembly.
The connector is a
disconnected
wiring. See
of
0!^
-t-4
dBu ouQ)ut
the
to
and ground is
that turns the
Connector
the input
switch closure
A
Wiring of Logic
preamplifiers
wire jumpers
discussed
as
available
all four inputs
wires, insert
the
rear panel
from the
Input
is on
Input
Connections
the tip of the
summing
on the
sleeve. The
channel ON.
in
the
in Preamp Gain
ground upon
to
drive external
to
Circuits
silkscreen
two-piece
of the
buss
may
be
pin
15
on Page
on
3-
See
7.
General
2.1
The following section
minimal reference
with
Installation
the
IMPORTANT—
Mixer,
operating
TTiis
Mixer.
please
understanding is
WARNING
gain
to
must be
2.2 Installation
access
exercised.
and
If
read
problems
:
many
In
internal
to
Setup
you
the short
These
Section Two Installation
contains installation and setup
areas of the
other
to
have
arise
phase
follows
never installed,
section on
because
important to
very
cases,
installation of the 7510B
circuit components.
instructions are
of an
manual.
immediately thereafter.
set
Theory
the
incomplete
ability
your
intended
information.
Supplemental
operated a
or
up
Operation before
of
incorrect understanding of
or
obtain
to
Automatic
Since dangerous
for
use by
Figure 4 The Rear
written in a step-by-step
It is
Information
Model
7510,
continuing.
which
7510A
how this product works.
the
qualified personnel only.
performance from this
best
Miaophone
voltages may
AC
Mixer involves opening
exist inside the
Panel
may
7510B
or
installation and
Most
-
Input
Section
procedure
of
use to you
be
Automatic
Automatic Mic
the unit
caution
unit,
in
Line
2.2.1.
the
voltage for which your
Check that
Voltage
Change
the
AC
Switch on
unit is
Voltage
rear
the
wired. The
at your
panel and
7510B
installation is correct
a tag
can
the AC
on
powered
be
power cord
from
the
Mixer.
which
Look at the
identify
for
either 100 to 120
the
VAC
position of
mains
AC
or 200
to
Page
5
Manual
751
OB
VAC,
240
operating
shipped,
As
1. Be
2.
3.
line cord
OB
NEMA
Canada. To
U.S. or
procedure:
751
a
Note
Listed
adaptor based
Caution
line
the
areas
WARNING:
CONNECTED
AND
or
50
60
range to
the unit is set for 100 to
sure the
the Supply
Slide
Install
a
uses a
5-15P plug
:
Any line cord or
or C.S.A.
:
This unit
voltage
within
mains.
Hz
the other.
convert the
7510B
suitable
standard
is supplied.
Certified.
governing local
on
may be
applied. Also,
the
U.S.,
Voltage
plug or adaptor to
DC
A SIGNIFICANT FIRE
TO AN
LABELLED.
The
Supply
120
for operation
unit
not connected to
is
Select
lEC 320
Cordsets to match
adapter
used
For 240 VAC,
regulations.
damaged
verify that
mains exist.
POWER
AC
Voltage
operation, and
VAC
Switch
mate
style AC
200-240
for
50/60
if
operated
the
AND
SOURCE
Select
with other
power
any
the
to
existing line
the
Switch
the
mains
source.
appropriate range.
the rear panel
on
line
cord provided is suitable
voltages or outlet
with the powCT receptacle. The
cord
Power Connector on the chassis. A
U.S.
FOR
available
or
other AC
Volt
Hz
with the Supply Voltage Select Switch
mains
SHOCK
OTHER
Mains
operation
operation
are AC since,
outlets are
in
the
in other countries,
in
some countries
HAZARD MAY EXIST IF THE MIXER
THAN THAT
converts
types, use
matching
worldwide.
Canada
must
select a
set
well
as
WHICH IT
the
unit from
for use in
the
following
cordset
U.L.
be
line
cord or
incorrectly
certain
as
RATED
IS
one
the
with
for
IS
2.2.2. If you
inputs above four,
2.4.4
and
2.2.3. Rack
Microphone Mixer
+122®
F
to
unit is installed
If the
(such as
while internal
avoid
Caution:
completed.
be
2.2.4. Connect
whys,
Input
power
mounting the unit
The
turned
wherefores and how-to's
Connections
have additional 75
do
this manual.
of
mount
will
F
and
up to 80%
),
amplifiers), adequate ventilation should be provided to assure longest component life. Also,
circuitry
lOB
75
Also, any power
OFF
all
until
audio input and
The Input Connector is
quick and
gold contact
you
&
connector
easy
have not seen
which may
wire, needing only
to
material
this
10-03
Follow
now.
it
your
operate
Mixer
satisfactorily over
the
with the enclosed rack
non-condensing
in
equipment
an
susceptible to
immediately
power cord
AC
amplifiers
wiring
a
eliminate oxidation or
to
be
and setup
pin
12
connector before, take
disconnected
rack, console or other area along
hum
adjacent to
should
output
wiring
of
connector
wire
from
Expansion Assemblies to
Input
instructions enclosed
with
mounting
range of ambient temperatures
a
relative humidity.
pickup
which
to
procedures have been completed.
wiring. The following discussions include a
the connectors.
which serves
strippers and
is sufficiently shielded
large power transformers, motors
not be
the Input Assembly
connected
Automatic
the
all
a small
corrosion of the contact surfaces
moment
a
to
the power receptacle
to
Microphone
four inputs on
screwdriver, and
examine
for
install,
the 7510-03,
hardware.
with high
from
a
it. You
ease of
wiring.
to
The Model
moderate electromagnetic fields,
Mixer
7510-03
in long
will
increase the number
or refer
Sections 2.4.3
to
7510B
0®
from
heat producing equipment
etc.
until
may
be
description of the
Input Assembly. It is
it
a reliable
is
term
notice that it is
polarized, and Ae
It is
+50®
C to
all
wiring
connect^
connector with
fixed installations.
of
Automatic
+32®
C
(
is
should
two-piece
a
Page
6
Manual
751 OB
latching
them.
although
AWG.
screws.
The Model
Phantom
not
Power
supplies
the nature
ON.
SWITCH IS
OR
Most
about
microphone
If none
Assembly
If
condenser
source is
series with the
751
to
mechanism
wires
The
may do
you
Strip tihe
7510B Automatic
Power gets
specifically
may
designed to use
turned ON
be
Phantom Power
of the
ATTEMPT
NOT
DO
ON.
THE MIXER
TO
microphones
the use of a
if necessary, its
or,
of your
wish
you
OB and its
avoid low frequency
inputs
turned
is
connect a
to
microphones,
transformer balanced,
input line. The
negative
is
are held
that
wires
designed to
in a
if
you
inch, insert into
1/4
make it easier to
device called
feel the need,
Mixer
from
name
its
it. This
Phantom
the
by
all inputs
to
phantom
SEVERE
circuitry it is not
USE
TO
DAMAGE MAY OCCUR TOTHE MICROPHONE ( OR
WHICH WILL NOT BE
designed for Phantom
specific microphone
manufacturer.
require
OFF.
lead
Phantom Power
Line level source
make sure that the
that is
capacitor should
connected to the source. A
rolloff.
the two
which
will accommodate a
Phantom
dynamic and ribbon microphones..
provides
fact
the
includes
connect
cage-clamp
a
ll^e
cage-clamp
the
+48
tiiat the DC voltage is
as indicated by
holes
volt DC
most
Power Switch on the Output
except
the auxiliary input located on
possible
to use
unbalanced connections with the Phantom Power
AN UNBALANCED SOURCE
COVERED
Powering will
with the
fine. Otherwise
7510B Mixer,
make sure that the
one of the
to
source
will
have its positive lead
BY
operate
consult
inputs,
not
you
capacitor of
but also
damaged
be
may need to install a
halves of the
not require
does
rear
the
Power for
invisible
connector than
that the wires be tinned,
wire range
panel silkscreen, and tighten
to disconnect
#14-#22
of
condenser microphones.
BALANCED
to
any
microphone
the
The Phantom
Assembly. Turning this switch
the
WHEN
Output
THE PHANTOM POWER
Assembly.
OTHER
Because of
SOURCE
ON
ANY MANUFACTURER'S WARRANTY.
+48
from
volts,
the operating instructions
Phantom Power Switch
need to
by application
connected
10p.F/50V minimum
but
if
you
have any
on the
supply
DC
to
Phantom
+48
of
blocking capacitor in
the input
volt DC.
terminal
rating should
for
the
Output
Power
of the
doubts
to
If
the
be used
Pre-arop_Gain_Adiusl
for
Preamp gain
Input
The
the factory the
from
for
each of the
removed and
only
a
good
for
the connectors are shown
four input channels. These
a resistor
quality
may
pin connector on the rear
15
may
or
1/8
externally adjusted
be
inserted
be
watt carbon
1/4
in Figure
in their
5.
jumpers,
place according
film
or metal
optimum
panel of the Input Assembly includes four wire jumpers, one
which
film
set
resistor
Wiring of Logic Circuits from Remote Control Connector
Figure
shows
5
Assembly.
provides a contact
can switch ±5 volts
gate
contact closure
just a
Figure
drive
television cameras
shows
6
Series
the
In addition to the Preamp Gain adjustments described in the
several examples of circuits
7400
pin
configuration
closure
for an
TTL logic,
in
a
ground
to
with
a
external
LEDs,
teleconferencing system
for
the
when
an input is activated.
maximum
current of 10
source.
which
switch loudspeakers
Remote Control Connector on the rear panel of the Input
milliamperes.
could
be used
OFF
etc.
signal-to-noise
gain
the
to
of the input preamp
the values
for
best noise performance.
previous
This
contact closure, made through
Note
with
this
provide
to
additional
and
headroom. As shipped
in
Table
that this
contact closure
1 on
section, the 7510B
is not
Acoustic
49 dB, may
at
the next
voltage
a
to
page.
Pin
a
source,
activate relays,
switch
Gain,
be
Use
numbers
also
CMOS
Page
7
labkl
Manual
751 OB
Qaitt
unity
4dB
Resistor
open
10
7dB 4.7
9dB
lOdB 2.7
13dB
14dB 1.5
16dB
19dB
3.3 kohm
1.6kohm
1.1
750
22dB 470
24dB 360
25dB 330
kohm
kohm
kohm
kohm
kohm
ohm
ohm
ohm
ohm
Gain Resistor
62
ohm
ohm
ohm
ohm
ohm
ohm
ohm
ohm
ohm
ohm
28dB 220
29dB 200
31dB 150
34dB 100
37dB
39dB 47
40dB 39
43dB 20
44dB 16
46dB 10
49dB Jumper
Pin
1 .
2
.
cn
VO
r-
00
ON
Number
--
Channel
—Channel C
-Channel A
Channel
Channel Logic Switch
J
Channel
Channel
Ground
Channel
C
(3)
(3)
(1)
D
(4)
B
(2)
D
(4)
A
(1)
Audio
Logic
Logic
Logic Switch
Audio
Audio Gain
Audio Gain
Figure 5 Remote Control Connector
Gain
Switch
Switch
w
n
Gain
11
11
10
t
Page
8
Figure 6 Logic Circuits
Manual 751
OB
Direct Outputs
from
A direct output
Input Assembly. An unbalanced 600 ohm
each input
between tip and sleeve of the
return to the
This is a
device, such
allow
Ae
etc.
possible
It is
connecting
Auxiliary
Auxiliary
The
which
Automatic
input into the
control of the
numbers of
output of
summing
patch point
as a
automatic
to
the tip and
Input
Input jack, located on
offers two
both feed
bus.
which
compressor
turn
on of
ring contacts
methods
Mixing function. Wiring
signal
path at the same
Number of Open Microphones (NOM) circuit, and therefore the gain
microphones
mixer. Alternatively, the input
the
channel is provided on a
three-conductor jack.
The direct
can serve
equalizer
or
individual channels,
summing
the
output
variety
a
bus
of the plug together.
the rear
of wiring
are turned
line level input into the 751 OB
a
signal
amplifier
ON. At least one input
inch phone jack located on the rear panel of the
1/4
source impedance,
The ring
follows
of
could be
the
of
panel of the
tip of the connector and ground
to
used
the
functions, depending on the
inserted here.
allow the separate
but
7510B
for summing all other inputs. Thisisthe amplifier
nominal
connection
channel
take
gnd
Output
ON
An
an isolated feed.
Assembly, is
must be turned ON
may
wired signal
be
to
44
dBu
provides
switching circuitry.
isolated output
mixer
1.23 volt
(
a
job. A
adjust
to
10
to
This
three conductor phonejack
a
which
ring of the connector and ground
are not under control of the
the sleeve
to
will change
for this
signal
)
kohm
signal
another
gain, equalization
is done
inserts the auxiliary
signal
is available
input impedance
processing
mixer
by
different
as
appear
to
would
under
at
the
to
the
Page
9
Manual
751
OB
sleeve
to
insert
the
signal
after
impedance.
Output
The
and
transformer,
output.
resistor.
at
possibility
An
ground.
Gain
connection.
Connections
output
main
pin 2 is
The
If the
other
the
unbalanced
The
control.
of the
(
the
- )
important to
is
it
output
will drive
7510B
the line
of
end
noise pickup
of
low
aiudliaiy
primarily
It is
7510B
of
side
driving a
is
impedance
output
Linkinp Two Mainframes
7510B
Two
Automatic
constructed
connection
which are
controlling
which
this
want
output
panel
front
microphones
required
microphones
Mainframes may be
Mixer with
link
to
is not
the
designed to
connected
audio
all
appear on
only
will
on both
mixer, or the
control of
of
signal
either
and 13.8
microphones
48
for
would
common
two
together
their
to
mixers, you
level
dB of
actually
NOM
the
Automatic
transformer
the
remember
load of
any
long
auxiliary
full
is
7510B,
lines.
from the
in those
intended
connected
control
mainframes
routed
be
should
individual
mixer to
the
mixer outputs
two
the
to
compensation.
gain
would be
ON
be
gain change
Mixer is
that
600
line
output
mixed
feed
to
of
together
through
remain
outputs
which it
must
different
only
one
at
circuit
a three
on
balanced output.
connection
ohms or
(in excess
combination
in
is
signal,
a tape
together to
NOM,
Priority,
at
must be
greater
of
30
available
controlled by
recorder
allow a
Interface
the
long cable
connected
except
is
connect
may be
areas.
dB
3
time.
together
for
wired.
them
used
Note
should
This
additional,
a situation is
Such
inputs
Both
pin
XL
Because
made to
and does
meters
with
at a
without
[100
the use of
inch
1/4
the
maximum of
Background
connectors
runs and relay
all
at
auxiliary
the
This may be
individually.
different
feed
to
the
that
present
and it is
kohin
10
are
connector.
output
the
both
not
feet]) a
phone
NOM
need
the
Threshold
contacts,
times.
input on
useful
System
areas of a
Pin
stage
and
(+)
norm^y
620
balanced
jack.
circuit, but
“
Y
to
inputs to
48
and
the Output
on
mixers
Both
rin^sleeve
the
in
some
audio
require
ohm
lines,
”
"rte two
facility
NOM circuit stops
problems
no
extremely
referred
to
as
unlikely that
pandemonium.
as
unbalanced
ground,
1
is
inccnporates a
terminals of
(-)
termination
a
termination
will
reduce
Tip is
signal and
unaffected
Main Ouq)ut
the
act
as a
audio.
A
Assemblies.
mainframes
operate as
connection
installations.
may be
^en
with
counting
additional
the
more
input
pin
is
3
(
Ae
resistor
the
sleeve is
Master
the
by
single
must be
cable
This
Masters,
If
you
from
the
convenient
24
after
decrease
24
than
+
mating
The
# DA15-P
plug
replaced
be
Table
either
reasonable to
plug
206471-1
with
gives the
2
connector
connector
with
is
a
DA-20961
Cable
with jackscrews
wiring
connection for the
may be plugged
connect
the two
pin
15
clamp.
allow
to
mixers.
D-subminiature
Mouser
Shell,
connectors
The
positive lock
a
interconnect
mixer.
either
into
plug.
Typical
mating
ME152-5015 plug
in the
on the
The
7510B
cable.
cable
are
mating
Note that
should
connectors
with ME152-4015
in place
held
connector.
the
constructed to be as
be
with
wiring is
would be
Hood
4-40
symmetrical,
TRW Gnch
745207-3
AMP
or
screws.
short as
These
and
that
Page
may
10
Mainframe
Table 2
Interconnect
Cable Piaout
Manual
751
OB
Connector #1 ConoectQf #2
Pin 1
Pin
Pin 5
Pin
Pin
Pin 11
Pin
Pin
addition
In
additional
with the
2.4.4
exactly
them
according
loading
changed
located
control.
the
Jack
equal
at
original
should be
on
3
7
9
13
15
to
inputs.
to
effects
from
the
you
If
part.
both
to
to
to
to
to
to
to
to
the cable,
This
mixers
two
alike so
Section
from
ohms to
300
bottom
front
wish, a
Following
measured
units.
that
2.3.4,
additional
second
Pin 2
Pin
Pin 6
Pin
Pin 9
Background
the
consists
linked
two
the
you may
150
of the
the
both
on
4
8
11
Pin
12
Pin
14
Pin
adjusting
of
together.
mixers
modules.
ohms.
printed
ohm
300
adjustment
units,
find
Threshold
the
The
the
act
the
that
If this
will
This
circuit
resistor
of the
the
and
Connector
circuits
Background
the
same.
control
found,
is
circuits
When
runs
resistor
actual
probably
assembly
board
may be
tacked
Background
Background
Pin 2
4
Pin
Pin 6
Pin
8
Pin 10
12
Pin
14
Pin
must
operate
setting
out of
require
just
on
Thresf
Threxho!
#1
to
to
to
to
to
to
to
adjusted
be
Threshold
independently, so
Background
the
range.
the
on
R63
removal
front of
in
parallel
in
” ’ -i.
control,
liold
controls adjusted
d
ConnectPri^
Pin 1
Pin
3
Pin 5
Pin?
Pin 10
Pin
13
Pin
15
operate
to
trimpots accontog
This
Output
the
of
the
with
corratly
is
it
Threshold
is
due to
the
Assembly
Output
Assembly.
Background
R63^stead
DC
voltage
to
the
with
Ae
Section
to
important to
control
increased
may be
R63
Threshold
removing
of
the
at
make the
voltages
align
is
Test
System Mute
circumstances
some
In
the
10 of
and
AUTO
to
ON.
having
maintained
system,
the
actual
some
In
attorneys
location
7510B does
level of
the
external to
mode.
feature
This
continue
to
action
that
position.
circumstances
and
wishes to
not
privacy
the
interface
Inputs in
enables
talking to
switch
it
be
judge
during
have
completely
required
7510B.
may
it
be
connector
mode
ON
individual
the
maintain
the
as
very clearly
be
may
it
a court
moments
few
a
turn
in some
necessary
will cause
will
in
PRIORITY
installation
labelled
necessary
session
for
any
OFF
situations.
Mute
to
mixer to
the
remain ON
PRIORITY
the
mode.
dictates.
function,
as to
completely
to
which is
private
audio
discussion.
input.
The
the
and
We
not
mute
entire
for the
system.
into
go
PRIORITY
position
installer
The
that
mute
turns
in
this case
re^mmend
all audio, as
record, or
It
it
highly
and
It
A switch
PRIORITY
inputs
shut
to
may use
have
it
must
down 25
a
in
remembered
be
would
contact
mode,
will retain
other
off
either a
if such a
that
clear
very
private
in a
teleconference
a
This may
dB.
have
to be
closure
their
OFF
ability to
turning
microphones
momentary
switch
visual
indicator
convCTsation
call
in this
insufficient
be
handled by
between
all inputs set
turn
without
or
installed
is
of its
by
where
context
that
circuit
a
Page
pins 9
in
one
the
for
1
Manual
751
OB
2.3 Initial
wiring
When
on.
you
If
all
Remember
don't
have
you
take
Background
Initially
set
Background
minimum.
ON
the
to
microphone
all outputs.
to
quality
If
channels
2.3.1
The
setting.
audio
have
you
Gain setting
optimum
But,
with
microphone
controls
having
naturally
is
similar
occur
changing
microphones
Turn-on
has
that
care,
mixer
a
Threshold
threshold
all
Threshold
Initially set
position
checked.
is
not
Do
hapnin'.
is
connected
MODE
the
front
to
due
distances,
adjust
to
signal level
as you
gain
the
in
a
and Trim adjustments
been
signal
the
that
with
trimpots, do
control to
the
at
one
initially
external
panel
use
the
this
exactly
for
adjust
the
of
system.
completed
level
lead to
may
more
trimpots
Master
time
a
front
The
concern
switch.
gain
of
goal is
the
at
the
input
the
will suddenly
some
four
than
now
it
their
to
full
the
Gain
the
and
panel
yourself
circuitry
an
these
wiper
system.
on
ideal
differences,
setting
different
preampUfier.
nasty
may
increase
feedback.
system
microphone
following the
position. Set
CW
full
clicked
CCW
control to
individual
LEDs
the
to
7510B
a
#7.
indicate
with the
logic
would
microphones,
which
will
and
control.
mix
the
of
Gross
differences
will
This
turned
be
inputs, and
preset
The
channel
that a
automatic
lines, the
have
different
rarely be
enable the
to
likely
on.
when a
have
procedure
all
position.
individual
controls
gain
channel is
circuitry
all input
talker
achieved.
variation
Some
actual
in
occur
Please
be
microphone
previously
not
Section
in
release
pots
Set
all input
channel
turned up as
ON.
may
gain
of
be
controls
functions
volumes
The
imx
audio
in position
setting
mixing
when
careful
very
channel
2.4.4.
full
at
gain
switches
mode
the
for
mixer.
Check
checked by
at
different
and
purpose
balanced,
to be
should
be
dynamic
during
is gated
adjusted
CCW
ON, and
the
rotation.
controls
should be
signal
from
signal
from aU inputs
Make
turning
approximately
source-to-
these
and
Input
with
controls
condenser
of the
of
compensated
initial
tim-
if
the
Set
to
turned
each
sure that good
the
ON
the same
Gain
all inputs
will
for
by
Many
of the
Gain
improves
condenser
preamplifiers
control
adjusted
be
the
source
adjusting
2.3.2
Each
rotation
increasingly
for
rotation.
level and
from
levels
the
Threshold Adjust
channel
of
adjustment
Turn
should
turning
completely
The 751
2.3.3
Each
OB
Release
channel
settings
for
input
for the
gain of
has
control
the
less
is
the
ON
prevented
should
has
counterclockwise
length
of time
that a
microphones
handling
roughly
input
any
headroom
Background
channels is
the
individual
an
the
is
sensitive
the
with
control
turn the
not
soon as
as
from
have
not
Time
Adjust
individual
an
rotation
channel
nominal
a
have
condenser
the
match
which has a
of
those
condenser
the
control
Threshold
discussed
screwdriver-adjust
sensitive
most
requires
and
control set to
Gain
a
counterclockwise
channel
should.
it
turning
any
the
of
will stay
ON.
Note:
Watch the
on.
noticeable
screwdriver-adjust
control
ON
output
microphones
the
of
setting
microphones,
circuit
in Preamp
position.
louder
sound
operating
its
only
Avoid
if
the
“
click
fastest
the
is
the
after
as
dynamic
lower
more
(
control
Turning
at
far
so
turning
control
individual
”
“
or
control
release.
input
as
much
should
be
microphones
than
#5).
which they
that in the
alxiut
Adjust
Gain
threshold
to set
the
input
the
and
point
prevent
as to
control
the
turned
is
channel
”
at
pop
release
to set
Turning the
signal
level
20 dB
turned
This
on
control
cause
to
the
false
too
fully
ON
channel
drops
dynamics.
down
any
than
to
event
so
the
higher
( in
accomplishes
more
and it
need,
next section
7.
Page
for that
charmel.
counterclockwise
channel
threshold
triggering
far
as
tum-on.
nimmer set
by
may
this
counterclockwise
LED to see
tum-on
for that
time
control
below
the
or tum-off.
channel.
clockwise
threshold.
the
that
preamp
two
closely
The
).
makes
sounds
prevent
actual
The
front
things: it
method
clockwise
Full
The
full
that
the
channel
the
tum-on/off.
Full
increases
Longer
gain
input
panel
gain should
matches
of
channel
the
starting
point
clockwise
low
are
channel
will be
the
release
Page
the
12
Manual 751 OB
prevent
times
timft
adjustment
the type
correct
setting.
the
Ideally,
quickly
will need
release
the
speech,
reverberant
Generally,
of
adjustment
Use
actual
the
that
longer
times
release
same
could
turn-off
exception to
microphones to
othCT
annoying to
person
the
after
2.3.4
The last
it is
Background
adjustment
not as
readjustment
channel
the
one of the
is
program
material
Your
channel
the
of
visually.
correct
it chops
church,
error
that
the
setting
release
therefore
are
time.
easily
be
might want to
on the
rule
participants
in
the
the ends
off
times,
In a
set to
side
is on
establish
Priority mode
Threshold
for
is
straightforward
as you see
exactly
turning
from
sensitive
more
environment.
the
and
the ears
and
ears,
LEDs
ON
be
short
words or
of
will
because
disturbing.
more
church
the
shorter
release
be set
longer,
of
microphone
a
in a
order
who will not be
has
Adjust
Background
as
setup
a
how the
between
off
adjustments,
the
of
again aid in
will
enough to
musical notes.
musical
That
release
rather
time
times
several seconds.
at
than
which
legislative
able
finished
Threshold,
those which
circuit
words
hard and
No
end users
the
off
cut
notes fade
not to say
is
for pulpit and
the
than
shorter,
in the
is
body.
have
to
speaking.
while it is
and
gone before.
have
responds
sentence, or
in a
partly because
rules
fast
largely
will
setting
fairly
of these
quickly
Typically
much more
away
that all
lectern
microphones
release
priority mode,
If the
their
in
time is
release
microphones
very
a
system
each
In
between
depends
it
can be
judge
after the
the
controls,
systems used
gradu^ly
microphones
microphones,
serving
better
the
is
and
fact,
time
good
used
is set too
turn back
circuit
it may
environment.
musical
a great extent
such
to
for determining
given
“
correcmess
for
will
music
as you
signal stops,
than speech. Short
given installation want
in
a
which typically
which, in
choir
the
choice.
to shut
One
off a number of
long it may be
on for
(when
require some
correctly
notes. Release
on
of
the
the
”
be able to
not
but
several
so
presentations
amplify
a
possible
seconds
adjusted),
level of
see
Background
The
time,
threshold to
but to
of
changes in the
to
adjust
audio
the
comparator
sensitive
multiple
when
position,
microphones.
environment becomes
the
Background
Ideally,
presence of
necessary
If you
up
Threshold
the
can stand
ON
channel LEDs
the
have
similar
two
channel
assuming
(
as
control
in
microphone
both
them
to
and at some
be
The
turned
control.
not
Threshold
“
signal
threshold
”
float
threshold up
the
from
and
for channel
knowing that a
Threshold
Background
the loudest
will decrease
this
moment,
a
microphones
in the
the
of the second
front
on
LEDs
you talk loud
are lit. As you
to turn ON
ON
turn
point it
circuit
on.
will
has
circuit
amount
depend
to
or
microphones,
all
When the
control sets
Threshold
expected
want
and
about
preset,
7510B. You
enough
continue to
when you
together
turn ON.
decided
allows
of sound
just
not
down
as
tum-on.
channel
environment
noisier, a
ratio
the
control
background
sensitivity
the
the
see
to
three
clicked
position,
can
microphone
).
speak
when you
distance
The
the
that
the
exists
that
on
“
the
turned
This
will
higher
of
should
effect of
apart and
feet
stand
and
Now,
advance
into
stand
signal
Automatic
what
noise
on or
allows
not be
quiet,
is
level
Microphone
in the
as an
you
”
in the
not,
you to
false
a
will
room.
low level
background
high enough
set
be
sound.
of the
turn
it
However, the
inputs
for
this
their
set
talk into
in front
turn it ON.
the
the
individually, but,
in the
will
which
first
of
Background
control,
middle.
depend on
it sees
Mixer to
This response
installer
changes.
room
amplifying
individual
the
set
triggered
required
be
noise to
program
for
yourself,
one
And
by
signal will cause
the
that
control
perform
gains to
microphone,
one
microphone
if
you
Threshold
will reach a
you
try as you
Walk toward one
setting of
the
common
in
decided is
have
This
using
it and
sounds
activate
to
threshold.
input
microphones turn ON
no
should
sound.
same
the
and turn it ON
stand
may,
the Background
“
is
noise,
respond
is to
dynamically,
allow the
the correct
is done
that
taking
by
varying
channel threshold
which are
the
not be set
following
the
point.
then
picked
channel
channels.
With the
other
the
tura-on.
higher
experiment. Set
by
in the middle you
you
”
clockwise
where
will not
that
and
you
while
the
control
point
microphone
in real
tum-on
threshold,
sample
a
level
to set the
controls
by
up
But
The
in
than
Background
watching
while
speaking.
turn
can
until
get
can
to
able
be
speaking,
Threshold
input
the
You
both
no
each
get
should
to
a
Page
13
actual
The
least
at
set
be
7510B works,
the
how
how
see
and
respond
they
Background
adjustment
enough
far
system
the
background
when
Threshold
the
of
CW
and
works.
control
Background
all
that
expectations
your
special
Pay
noise
if it is
CW,
Threshold
channel
present
is
too
control
LEDs
ON
how the
of
attention to
in the
insensitive,
will
extinguished.
are
system
how
room.
turn
involve
should
individual
the
If
the
it CCW.
some
After
work, set up
threshold
Manual 751 OB
error.
and
trial
that, using your Imowledge of
all
inputs
trigger
appears
too sensitive,
Initially,
of the microphones
and to how
ON,
must
it
turn the
There
poformance
are,
example
should
The
Use
both
more
is
activate
Background
two
of
presented
in
care
microphones
circuit.
the
turn ON.
inhibited
circuit
the
CCW
Or a
Choirs
by
by
from
combination
where
the
one such
is
Threshold
microphones
to
adjustment
the
pick
can
would
This
should
Background
the
rotating the
current
the
course,
of
2.3.5 Priority Set
inputs
All
chairperson
does
mode
OFF
normally
to
wish
not
switch
when the
take
to be
for the
person
installations
7510B is
the
individual
application.
on
7510B
the
the same
up
result
be picked up
control to
position,
these
of
should be
control of
interrupted
chairpersons
the
in
^ing used
channels.
circuitry,
lectern
a
single source.
a
as
the
of
the
in
Threshold
3.
methods.
set to
meeting
the
while
microphone
Priority
where the
in a
The
its
by
single
for a
Background
pro^am
microphones
one
by
circuit
its CCW
the one
Put
AUTO
to
he/she
position
threshold
situation
of the
use
nature,
does
talker
Similarly,
Threshold
material
having an
microphone
are
there
clicked
important
speaking.
is
PRIORITY
to
speaks.
In
mode.
establish
individual
of
where
7510B
like multiple
not
not
does
wireless
Control.
should be
artificially high
only,
sever^
position,
channel
meeting
order.
That is the
channels
gate
work
levels
on
unless
signal
to
and
Any situation
very carefully
if possible.
methods
Desensitize
2.
Priority mode,
in
rooms
It is
and
it
frequently
also
purpose
microphones
all
should
common to
footlight
microphones
the
layaliCT
for
is
microphones
checked.
threshold,
If channel
resolving
circuit by
the
sometimes
of the
“
float
not
multiple
microphones
on the
ntics are
in
the
in the
premixed
which
Priority
multiple
is
It
possibly
and
triggering is
problem:
the
turning the
4. Re-adjust
necessary
that the
case
AUTO
”.
An
microphones
in
theatrical
same source.
and then
require
may
possible
to
failing
being
l.Tum
thresholds.
for the
chairperson
mode.
Switch the
mode
fool
to
off
control
will shut
sometimes
is
It
than
more
switched
be
simultaneously.
mode.
by
2.4
The
the
2.4.1 Impedance and
In
telephone
reproduction
And,
which
Supplemental
following
installer.
USA
the
Telephone
design and
transmission
The
transmission
600
ohm
necessary
person
one
PRIORITY, and
to
For this
if there
will be
order
sections
early
the
industry.
sound
of
Laboratories.
specification
line.
was
line
Transmission
lines.
is more
Much of
in larger
to be
needs
reason it is
than one
established.
Installation
contain
Termination
history of
the
either
was
technology
The
all types
of
developed
systems to
to
single
very
input
establish
Priority
important
switched
able
no
Information
supplemental
for
600
industry
audio
the
equipment
early
designed
of
by
that they
audio
because of a need
reception
and
has
not to
into
than
Any
Priority,
have more
order.
input
information to
Ohm Lines
very closely
is
for
used
heavily
or
and
products.
equipment
influenced by
others
Among
standardized
for a
switched
input
one
all of the inputs
number
control over
establish
previously
that
public address systems,
developed
their
or
Priority
other
microphones
many
too
participants must
the
presented
tied to
the history
the scientists
has had a lasting
contributions was the
impedance
using
vacuum
tubes,
Priority
to
on
inputs.
in the
agree
which
technology
and
recording,
engineers
and
influence
600
distance
long
for
transformers,
mode,
because
7510B may
the
All may be
Priority
the
on
may be
of
broadcast
at
on
ohm
passive
and
method
of aid
the
and
Bell
the
Page
on
to
14
Manual 751 OB
equalization
Because
gimilar
audio
Correct
much
types
industry.
use
impedance,
correct
impedance,
impedance
of
case
the
actual
in a
one
modem
longer
network
600
270
First
between
are
resistive
The
used
(or
Most
reasons.
cabling
products
is no
impedance
signal
of
loss
mixing
and
of
equipment,
of
the
of
a
and
would
this
higher
a
output
ohm
resistor
ohm
audio
most
parts
longer
no
necessary
high.
very
level.
networks
early
the
ohm
600
receiving
must
it
require
impedance
transformer
or
source
system,
systems
audio
of
designed to
because
Multiple
require
professional
not
is
it
transmission
device
modified
be
addition
input a
to
impedance
out
build
leg
each
in
not
do
systems
the
are
system
the
inputs
known
audio
surprising
line
until
of
resistor
match
the
of
output
the
a
of
require
relatively
under
is
require
also
a
impedances.
balanced
impedance
which
output
may
source
equipment
that
requires
has
it does.
series
across
751 OB
impedance
the
use
small
more
use
the
thus be
and load
was
ohm
600
the
signal
a
ohm
600
a
the case
In
buildout
is
system.)
of 600
careful
of
connected
resistor
input
the
approximately
with a
ohm
(especially as
control,
ohm
600
device
a
of
impedances
designed
became
line
source
input
will
with
impedance.
device
of a
(or
suffice.
40
560
transmission
compared
and
Matching
line.
be
may
parallel
in
telephone
by
an
in the
two
ohms.
ohm
second,
made
to
achieve
to
standard
a
exact
If a
with
a
case
Other
Therefore,
resistor
line
to a
modem
of
very low
same
the
predictable
company
in the
ohm
600
device does
than
lower
of a
variations
if
series
in
practices.
telephone
audio
input and
and
source
results.
people,
professional
source
have the
not
required source
balanc^
require either
the
with
This
line).
7510B
the output
for
is
network)
elecfronic
the
input
impedances
ease
output
with
or
used
In
is
to be
two
and the
and
a
no
2.4.2
For
for
path
from
regulations
through
In
Groundmg
safe
voltage
any
the
external
many
operation
unit
a
situations
troduced
been
some
the
connected.
instances
between
has
In
mechanical
signal
prong to
line
2
Determine
ground.
2.4.3
This
Installation
CAUTION
and
OFF
which
might be a
fields
many
in
three-wire
to a
due
audio
ground
allow
may
prong
which
normally
is
:
When
the AC
OB
751
the
might
shock
minimizes
and
localities,
will
cord.
present
power
this
phenomenon
voltage
not
is
the
adaptor
of
possible
signal to
ground
the
AC
connection
made
7510-03
of
removing
power cord
be
must
hazard.
radiation
to
and
on
appear
no
known as
previous
the
difference
without
be
between
works
through
Input
installing
or
unplugged
is
connected
chassis
the
addition, a
In
protect
problem.
a
piece
between
hum
connected
power
the
Remember
best.
properly
a
Expansion
from
to a
due to
internal fields
of
customers,
our
But
ground
equipment
of
the
the
in
while
cord
Input
an
the
mechanical
good
severe
a
quality
good
we
are
there
This
loop.
grounds
output.
maintaining
the
and
for
that
grounded
Assemblies
Output
or
mains.
AC
electrical
ground
outside
the
to
provide
instances
results
and
will
Use
when
mechanical
the
be so
an
of
ground
power
safety
third pin
outlet,
vou must still
Assembly,
fault
the
on
world.
product
Tbis
^ound.
this
where a
there
that
^eat
isolation
isolation.
temporarily
connection.
sure
make
provides
mixer.
in the
chassis
hum or
is a
provides
comply
To
with a
buzz
significant
ground to
direct
a
transformer
Check
ungrounding
have
a
AC
the
current
a
Without
shielding
safety
with
will
potential
connection
be
ground
which the
connection
input
the
in
using a 3
this
for
connection to
Power
is
path
this
in-
7510B
to
unit
the
chasiis
turned
.
Unscrew
unit.
be
gently
1
of the
need to
screwdriver
and
Panel.
the
early
On
removed.
access
lift the
versions
It
the
to
Cover
will be
screw.
away
#6-32
three
machine
the
of
necessary
Insert
from
screws
7510B a
to
your
Front
the
from
single
remove
fingernail
Panel.
each side
screw
plastic
the
between
Do
through
Cover
the top
not use a
of
the 75
the
Plate
sharp
lOB top
center
at
of the
tool as
cover
of the
top
location to
this
Cover Plate
may
you
and lift
front
gain
and
scratch
the
panel
full
the
the
cover
will also
Front
Front
Page
off
Panel
15
Manual
751 OB
2.
where
the
removal
.
3
Front
the
may be
4
.
are
you
controls,
gain
removed
.
5
6.
position
the
may be
shaft
expanded
be
7 .
Output
and
Reinstall
Reinstall
single
new
the
the
Input
Input
the
of
of the
all
it top up
Assembly
Assembly
Front
the
Remove
of
Remove
Panel
discarded.
Place
holding
switches
hold
2 to
Step
at
flat
of
the
the
the
four
control.
Attach
Install
squeezed
slightly
Reinstall the top
by a
Assemblies
screws
six
the
the
Cover
Plate
#6-32
Panel
7510B has
and
and
switches
insert
LEDs go
Input
the
cable
on
Mode
ribbon
knobs
The knob
slightly
small
cover.
into
slide
holding
was lifted
that
machine
(are) to
is
(ies)
contemplated.
is
already
Plate(s)
been
Cover
on
new
the
into
Assembly
the
to
Gain
the
is
a
with
shut
screwdriver.
cover
The
slots
the
cover
the
off to
that holds
screw
installed.
be
Save
the
at
labelled
new 75
the
Assembly
Input
their holes
into the
connector on
Make sure
pots.
push-on type.
pair
a
slides
on the
( and the
pliers.
of
over
top
seventh
gain access
the
The
screw.
the
location(s)
accommodate
to
10-03
Input
into
on the
cover.
Front
chassis.
the top
that
If it is
Conversely,
the top
to
The
screw
the
filler
for
of
plate
the
bottom
Assembly
mainframe,
the
Panel.
new
the
of
index
the
hard to
very
rear of the
front
through the
Front
rear
the
may be
Input
new
additional
the
into
Install
Input
line is
if the knob
mainfi-ame
end
Panel screw
the
Assembly.
correctly
push the knob
of the
Front
filler plate at the
discarded unless
Assembly
inputs.
centCT
the
sliding
#6-32
(ies). Note
The Clover
position,
forward so
it
machine
oriented to
onto the
very loose
is
and the
cover then
Panel, if
).
tabs
pivots
necessary.
location
screw
shaft may
the
the
on
down.
future
that
Plate
make sure
that the
indicate
shaft, the
Input
2.4.4
The
be
Adjustment
level
low
readjusted
Expansion
rack
in the
adjustment.
1 .
While they
with
Set
Set all input
Note:
control
this
2.
connected at
3 . Set
4
5
rotation
6.
Output,
above
.
.
Set
Set
).
Connect the
bushing of
the green
through the
Background_Tiireshold
of
Background
whenever
Assemblies,
completely
and
knob
all input Mode S
time.
this
all Release
Threshold
all
Front
the
the
or
the same
affect
labelled
channel
controls to
Panel
negative
phone
POWER
unlabeled
hole
Threshold
75
lOB
when
wired.
Background
witches
Gain
controls to most
Trim
input
existing
an
circuitry,
Threshold.
AUTO.
to
controls to
fastest
Background
high
a
of
lead
jack
LED.
Connect
).
Adjust trimpot
front
in the
panel
Control and
capacity is
Input
these
“10”
response (
sensitive
Threshold
impedance
positive
the
RT-1
just
Controls
Trim
the
increased
or Output
controls
trim
Resetting
maximum
(
maximum
position
Control to
digital
lead
for
above
the test
Background
adding
by
Assembly
serve
the Front
of
CW
CCW
maximum
(
switched
its
voltmeter
the test
to
reading
a
jack.
Threshold
one or
is
different
more 75
changed. This is
functions
Panel knob
rotation ).
rotation ).
to Chassis
jack through the
of 0.30
No
rotation ).
CW
preset
volts positive
Preset
Trim Control
10-03
than the
not
is
microphones
position (
Ground
front
DC.
Input
with the unit
done
Front
substitute
a
should
maximum
of
pin 1
(
immediately
panel
Trimpot
must
Panel
for
be
CCW
XL
RT-1
is
7 .
Turn
Background
Panel
Front
the
Threshold
control to
“
”.
1
Page
16
Manual
751 OB
trimpot
and
On
Turn
the
of
Rotate
Rotate
retiim
7510Bs
the
of
Channel
8.
Several
9 .
10
stop
Note:
rotation
2.4.5 Security
installations
some
In
mis-adjustment.
dust.
and
dirt
Model
The
Automatic
the
to
display
Installation
screws
not to
excess
requirement
SC-7
Microphone
panel
front
status
of
through
scratch
curiosity
may be
the
being
RT-2
ON
clockwise
RT-2
panel
front
the
until
RT-2
only
>vith
Background
Cover
may
it
In some
Security
Mixer.
of the
the
the
front
of
unit
viewed
Security
holes
panel
some
4-40
the
people.
counter-clockwise.
fully
until
will
all
LEDs
Background
or
one
necessary
offers
The
four
with
through
is
cover
with the
OFF.
two Input
Security
simply a
they go
Threshold
be
environments
Cover
Cover
the
in
The type
thread.
light.
LEDs
Threshold
Repeat
control.
safeguard
to
controls
the
protection
4-40
x
cover
the
screwing
and
screws.
and
Trimpot
off.
are
control
until no
Assemblies
This is
may
for all
1-3/4
after
Some
style
is
inch
installation.
of
them
installations
of
Cover
matter
RT-2 is
through
LEDs
LEDs
the
acceptable.
7510B control
the
benefit
operating
five-sided
a
Phillips
into
screws is
it
the
placing
such
just
throughout
light
may
from
controls
box
head
against
holes
may need
above
full range.
its
ON
turn
settings
additional
of
smoked-gray
of
machine
front panel
the
provided on
tamperproof
left to
the
RT-1
If
range
the
the
at
from
protection
JBLAJREI
the
screws.
the
installer,
on the
any
front panel.
LEDs
the
of
extreme
deliberate
against
model
plexiglass.
Control
of the
panel.
front
screws
the
come
control.
clockwise
accidental
or
entry of
It
positions
pushing
unit,
due
only
ON,
7510B
attaches
Take
the
to
and
the
care
The
Security
Cover may be
IMPORTANT NOTE
following
The
may
user
Service
on
5PRVTrF
this
of
rear
3.1 Input
input
The
level
low
external
microphones
for
condenser
Input
The
another
ON.
contacts
operational
The
descriptions
this
ART.F
general
product
PARTS INSIDE.
have a
manual,
Amplifier
amplifier
microphone
resistor
on
of
microphones.
control
Gain
output
of the
of this
patch
the
of
understanding
should be
assist
will
hybrid
a
is
signal.
Remote
different
located
is
amplifier,
amplifier,
Output
point
cleaned
the
your
design
The
Control
nominal
the
with any
used
how the
of
Three
Section
circuitry
performed
Reference to
understanding
using
gain of the
connector
output
following
which is
of
gain
through a
and
jack
mild,
in the
only
low
amplifier
levels.
first
the
600
the
to
non-abrasive
Theory
mixer
works.
mixer
qualified
by
block
the
of the
noise
following
transistors
may
rear
the
at
+48 volt
of
stage
varied
ohm
audio
from
buildout
summing
cleaner
Operation
of
presented
are
They
technicians.
diagrpi
of
sections.
and
reduced
be
to
panel
Phantom
amplification.
unity to
resistor
buss.
a
and
here
are not
THERE A
the audio
operational
49
from
optimize
Voltage
Following the
+
dB
25
is routed
cloth.
clean
that the
order
in
intended as a
RE NO USER
control
and
amplifiers to
dB
to
unity
signal-to-noise
available
is
Input
channel
the
when
through
the
professional
for
guide
circuitry, at
ampltfy
addition
by
headroom
and
powering
for
Gtun
turned
is
normalling
service.
the
the
of
of
control
an
is
Page
17
Manual 751 OB
signal
under
Amplifi
from
control
gain
feedback
gives
Summing
3.2
Audio
The
amplifier
appropriate
the
prevent
following
Number
is
system
table
of
Microphones
1
2
3
4
5
6
7
8
3 3 Threshold and
er and NQM Circuit
combined
is
NOM
the
number
give
gain
the
for
the
all
that
inputs
of
and
exact
Gain
OdB
-3
dB
TTSb
-6
dB
-7
dB
-7.8
dB
-O^B
-9
dB
Background
circuit.
inputs
of
maximum
increments
Number
Microphones
Threshold
in an
The
increments
and
system
the
of
Table 3
of
9
10
11
12
13
14
15
16
amplifier
circuit
NOM
gain
NOM
NOM
on
the
for
circuit.
Gain
Gain
-9.5
-10
dB
-10.4
-10.8
-11.1
-11.5
-11.8
-12
the
counts
gain
Ae
dB
dB
dB
dB
dB
dB
dB
Output
the
the
of
actual
Assembly.
numbw
of
summing
live
number
Number
of
of
Microphones
17
18
19
20
21
22
23
24
gain
The
active
^plifier
of
inputs,
accordingly
microphones. The
Gain
-12.3
-12.6
-12.8
-l8
-llidB
-13.4
-13.6 dB
-13.8
this
calculates
to
dB
dB
dB
dB
dB
dB
audio
The
voltage
A zero
zero
adjustment
that
in
panel
the
The
In
and
position, a
channel
between
which
crossing
volts,
comparator
the
audio
the
LED to
panel
rear
comparator
fixed,
the
feeds
tum-on.
the
3.4 Output
Following
output
the
amplifier
3.5
takes
Power
drives
detector
thereby
the
of
chain.
indicate
on any
eliminating
DC
signal
remote
threshold
preset
establishes
rectified
position
The
of
level
Amplifier
output
the
transfomier
signal
Supply
channel,
comparator.
a
circuit
voltage
ON.
held
is
gain
The
the
that
control
may
threshold
the
voltage
DC
Background
Gain
which
before
provided by
control,
signal
taken
restricts
tum-on
any
required
level
The
change
channel
connector
either
be
Background
the
of
level
representative
Threshold
an
the
gives
output
the
from
voltage
the
If
the
circuit
dB.
25
is
is ON
for
fixed,
for
individual
an
operational
unit
Gain
wiper of
the
channel
due to
pop
threshold,
for
drives a
The
and a
external
or
Threshold
channels.
all
each
of
contro
fully
a
control
exceeds
from
waveform
switch
circuit
switch
third
switching.
vary
may
input
changes
channel to
amplifier
floating
and
channel
the
comparator
the
turning
and a
that
also
with the
control a
When
signal
the
driving
output
the
feeds
gain
until the
ON
truncation.
release
changes
drives
which
another
provides a
sum
fixed
control
the
summed
is
of
gain
provided
that
complementary
a
the
at
Auxiliary
control,
threshold
A
trimpot
the
the
of
DC
is
amplifier to
an
connector.
XL
Output
is
audio
threshold
allows
gain
of
switch
contact
audio
voltage
turned
establishes
and
the
by
convated
channel
the
signal
trimpot
adjustment
operational
an
which
closure
signal
set
is
of
out
adjust
of
sum
pair of
second
A
jack.
to
is
crosses
turns on
to
from
trimpot
with
detented
its
thr^hold
the
the
channels.
all
transistors
a DC
ON.
gated
through
allows
time
the
of
amplifier
front
a
ground
channels.
all
RT-1
ratio
drives
operational
on
for
converted
1.5
for
A,
is
T1
and C19
-8
8
AG
supplies
VDC,
mixer
mains
AC
style.
is
DC
VDC,
protected by
power to
Stepdown
filtered
for
Q2
an
the
transformer
capacitors C18
by
VDC,
+8
internal
Q3
fuse
to DC
voltage
low
regulated
and
+15 VDC
for
Q4
(Littlefuse
the
in
36101.5)
power
AC
by
supply.
bridge
to a
Integrated
and
Q5
mounted
for
The
rectifier
Circuit
-15
VDC.
next
supply is
BRl. The
Voltage
The
the AC
to
straightforward
a
wave
full
Regulators
power
supply
Voltage
Change
rwbfi^
for
Q1
is
Page
linear
+5
switch.
18
Manual
751
OB
Phantom
The
circuit,
protected
4.1 General
providing low noise regulat^
The Model
provide
SPEQAL
NO
SERVICE
The metal and
heavy dirt, a
of
SPRAY THE
LUBRICANTS
clean the
Power supply is
7510B
of trouble fipee
years
all
is
solid
PREVENTIVE
ADJUSTMENTS.
plastic surfaces
non-abrasive
CLEANER DIRECTLY
USED
unit.
IN
THE SWITCHES
4.2 Repairs and Warranty
This product is
warranted
workmanship for a
sales receipt for
dated
period
by
of
proof of
configured
+48
Section
ruggedly constructed and uses
state,
normal
with
use
MAINTENANCE
Automatic
of the
household
ONTO
module
as a
for
Volts
Four
care.
Microphone
cleaner
such
THE FRONT OF
IS
AND
manufacturer to the original
the
two years
warranty status should
firom the date of purchase.
board. It is a voltage
on the
phantom
main ou^ut
microphones.
PC
The
siq>ply
Maintenance
components.
finest
the
for their application.
All
parts are
conservatively
rated
REQUIRED, AND THERE ARE NO
widi
IT MAY DESTROY THE
cloth
that
and
you
a
Formula
as
Mixer
may be
409 or Fantastik may
THE
cleaned
UNIT AS
CONTROLS! Spray onto
purchaser against defects
We
suggest
that
necessary.
be
tripler
is overcurrent
As
such it
will
INTERNAL
cloth. In
damp
a
NOT
used.
be
then use the cloth to
in material
retain
DO
and
a copy
of
case
your
If
can
it
substitution or
If
you
Service address listed on
the
returned to
detomined
be
wish
that the
otherwise, it
to
the
return
the unit directlytothe
factory must be accompanied by a
defect is
only necessary
is
the tide page
COD shipments will not be accepted.
For
that
prompt
it
well packed
is
service,
ship
in
pack" surrounding tire
drift
the unit cannot
covered by the JBL/UREI warranty.
name
product. We
Field repairs are
personnel may
and
phone
a
will
around
number
pay
normally
not
invalidate
Customers outside the USA
assistance. Do not
return products
do so.
the
a sturdy
unit
where we
return
the
unit
to
carton, with shock absorbing
partiedar attention to
Pay
in
shipping
the
shipping
authorized
warranty.
should
to
associated
factory,
of this
the factory
box.
Tape a
may contact
on any
costs
during
contact their local
the factoiy
with
return the assembly.
to
please
manual
Return Authorization Number, and must be shipped prepaid.
with
Shipping
note
to
you
repair covered under the
the
for repair unless
one of
call
for
RA
the
protecting
damage
the
top
necessary,
if
warranty
JBIVUREI
in
plug
the
write
or
Return Authorization Number.
a
number
material such
of the
period,
to
marked
the controls and switches and
caused bv inadequate packing is not
describing the
unit
give
and
and
Professional Products dealer
have been
you
or Output
Input
the Customer Service
on the
as
us
terms of this warranty.
repair
shipping label. Be sure
styrofoam
problem,
instructions for returning the
attempts
givoi
Assemblies
Dq)artment at
All products
pellets or "bubble-
make sure that
include your
unqualified
by
warranty
for
specific
instructions
by
to
Page
19
Manual
751 OB
Input
Input to
Input to
Input to
Maximum
Equivalent
Frequency
Main
Impedance/Load:
Ouqiut
Maximum Ouqiut
Input;
Impedance:
Gain;
Direct OuQiut:
Aux Output:
Main
Output:
Level:
Input
Input Noise:
response:
Output:
Approximately
Level:
Differential
kdim
6.8
Channel ON,
(One
Adjustable
Adjustable
max.
70 dB
max.
dB
77
-f
dBu*"
17
-129
dBu
±1 dB, 20
Floating,
40 ohm source.
impedance
+24
dBm
Hz -20
(20
amplifier. May be
kohm
balanced,
19
25
with
(15.7
Hz
transformer-isolated.
loads.
with
kHz).
3.4
Input and
64 dB
to
to
70 dB
(600
(10
kohm
minimum input gain,
kHz Noise
•
kHz
20
than
less
Bandwidth,
any
Designed to
0.4%
balanced
used
unbalanced.
Output
ohm load).
load).
input to
drive
THD
unbalanced,
or
controls
Gain
-24
150
dBu
ohm
with
any output.
ohm or
600
max. into 600
full
maximum
source).
higher
ohm load
CW),
bridging.
±1
dB.
input
gain.
Auxiliary Input
Impedance:
Input
Maximum
Auxiliary Output:
Impedance/Load:
Ouqnit
Maximum OuQ)ut
Direct
Impedance/Load:
Output
Output:
Maximum Ouq)ut
Automatic
Attack
Input
:
kohm unbalanced.
10
+7
Gain;
dB
+7 dB
Input:
+18 dBu
47 ohm
loads.
Level:
Level:
+20 dBu,
ohm
600
impedance
+14 dBm,
dBu,
+20
Mix:
Time: 10 ms to
threshold).
(input to
(input
to
(6.15
unbalanced
less
@
unbalanced
loads.
less
@
less
@
ps
10
other
tip, no
ring, output
volts).
source.
0.1%
than
source.
than.1%
than .1%
cycle
(1/2
inputs ON, ouq>ut
control
Gain
Designed
to
THD 20Hz
Designed
THD 20
THD 20
from 20
to
Hz
Hz- 20
Hz to 20
full CW).
drive 2
-
20
drive
-
kHz
20
kHz
kHz
Gain
kohm or
kHz.
600
(600
(10
after
control
higher
higher
or
(Am
ohm
load).
kohm load).
signal exceeds
full
CW).
impedance
30-60
Input Rise
Time:
ns
(tolerance for
tum-oi
once attack
occurs).
Page 20
Manual
751 OB
Release Time:
Input
Channel
Feedback
PHYSICAL;
Depth Behind
Requirements:
Power
Environment:
*
0
dBu
=
0.775
Attenuation:
Prevention:
Panel:
Front
Panel:
Finish:
Weight:
Net
V RMS
OdBm
100ms
dB
25
dB
3
133
283
Black
Chassis is plated
6.4 kg
kg
0.6
105
Operating.
Storage. -20®C
s
mW in 600
1
seconds,
to 5
overall gain
X
mm (5*1/4
483
mm
(11-1/8
Anodized
14 lb.
(
1
lb. 3oz.
(
VAC or
125
to
0®C to
adjustable.
decrease
in).
Aluminum
steel.
Mainframe with one
)
)
for each
x
in)
19
Front Panel.
Additional
210-250
EIA
7510-03
VAC
+50®C.
+60®C.
to
ohms.
doubling of
mount
rack
Assembly
Input
Input
switchable.
number
Assembly
50-60
Hz. 30 W max.
of active
iiqtuts.
Accessories:
7510-03 Input
Security
SC7
Expansion Assembly
Cover
Page
21
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SUPPLY
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RT-3
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IN
NON-DETENT
POSITION
2
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CAPACITORS
IN
MICROFARADS.
CAPACITORS
LABELLED
XX/YY
ARE
ELECTROLITIC.
XX
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YY
IS
VOLTAGE
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RESISTORS
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NOTES
I
(UNLESS
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