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EQUALIZER IN/BYPASS Slide Switch
-
Disables
filters and LEVEL Control in BYPASS position and
returns gain of Equalizer (LINE INPUT to LlNE OUT-
PUT) to value determined by rear-panel GAlN Con-
trol.
LEVEL Control -Operative
only in EQUALIZER IN
mode. Provides adjustment of Equalizer output level
of + I 5 dB to compensate for changes in gain re-
sulting from Filter adjustments.
OVERLOAD LED
-
Provides peak signal visual in-
dication when peaks in output signal approach
actual clipping level of output amplifier.
POWER ON/OFF Switch
-
Controls ac power to
unit.
Power-On lndicator Lamp
-
Indicates ac power is
being applied to unit.
30 VDC Accessory Power Jacks
-
Provide 31 Vdc
open circuit (27 Vdc at 10 mA max.) for accessory
equipment.
AUX OUTPUT Phone Jack-
Provides unbalanced
low-impedance output for connection to audio con-
sole or amplifier-mixer link input.
LlNE OUTPUT Phone Jack
-
Provides balanced or
unbalanced line level output to power amplifier.
MIC/LINE Slide Switch
-
Connects line level or
low-impedance microphone level signal to 3-pin
OUTPUT Connector.
OUTPUT 3-Pin Male Connector
-
Provides bal-
anced output at either line level or low-impedance
microphone level as selected by MIC/LINE switch.
May be unbalanced externally.
GAlN Control
-
Provides gain adjustment range
from UNITY to +20 dB to accommodate various
input and output requirements. Operates in both
EQUALIZER IN and BYPASS modes.
LlNE INPUT 3-Pin Female Connector
-
Provides
balanced bridging, high-impedance input connec-
tion from audio console or mixer-preamplifier. May
be unbalanced externally.
LlNE INPUT Phone Jack
-
Provides balanced or
unbalanced bridging, high-impedance input con-
nection from audio console or mixer-preamplifier.
Ac Grounded Line Cord -Connects
unit to ac
power source (SR107 only).
VOLTAGE SELECTOR Slide Switch
-
Permits se-
lection of 105-125 or 210-250 Vac 50/60 Hz opera-
tion (SR107-2E only).
AC (MAINS) POWER 3-Pin Connector
-
Connects
unit to ac (mains) power source via supplied line
cord (SR107-2E only).
General Operating Instructions
The SR107 Audio Equalizer is primarily intended for
connection in a sound system between the output of an
audio console or mixer-preamplifier and the input to the
power amplifier(s). A typical installation provides a line
level input to the Equalizer and utilizes its line level out-
put to drive the power amplifier. In a system using a
limiter or compressor between the mixer and power am-
plifier, the SR107 should be connected between the
limiter or compressor and power amplifier to achieve
best signal-to-noise performance.
An alternate location for the SR107 is between the Link
Out and Link In jacks of a console or mixer equipped
with these jacks. The SR107 can provide satisfactory
operation at the lower signal levels characteristic of this
location and is equipped with an auxiliary output of ap-
propriate level for the Link In connection. In the follow-
ing general operating procedure, variations in connec-
tion for Link operation are indicated where applicable.
1. Using hardware provided, install SR107 Audio
Equalizer securely in standard 19 in. (483 mm) rack
or optional A30A or A105A Carrying Case prior to
making electrical connections.
2. Connect audio console or mixer-preamplifier line
level output to SR107 LlNE INPUT 3-pin connector
or phone jack (13. 14). (For Link use, connect link
output of console or mixer to either SR107 LlNE
INPUT Connector.)
3. Connect SR107 LlNE OUTPUT phone jack or 3-pin
OUTPUT Connector (9, 11) to power amplifier input.
If 3-pin connector is used, place MIC/LINE Switch
in LlNE position. (For Link use, connect SR107 AUX
OUTPUT (8) to link input of console or mixer.)
4. Place all Filter Controls (1) and LEVEL Control (3)
in zero position. Move EQUALIZER IN/BYPASS
Switch (2) to BYPASS. Set GAlN Control (12) to
UNITY. (For Link use, set GAlN Control to $20 dB.)
5. SR107: Connect ac line cord (15) to grounded 108-
132V, 50/60 Hz ac source.
SR107-2E: Move VOLTAGE SELECTOR Switch (16)
to 115V or 220V position as appropriate. Attach
suitable &pin male power plug to ac line cord and
insert chassis connector into AC (MAINS) POWER
Connector (17). Connect ac line cord to grounded
105-125V or 210-250V, 50/60 Hz ac source.
6. Position speakers in desired operating locations
and aim for uniform coverage of audience area.
Position microphones (if used) as required by per-
formance or application involved. Basic precautions
relative to
microphone and speaker
locations
should be observed to reduce feedback potential.
Set all tone controls in audio console or mixer to
their zero or flat position. Set output phase switch
(if any) to 0" or in-phase condition.
7. Apply power to sound system. Place POWER ON/
OFF Switch (5) in ON position. Power-On lndicator
Lamp (6) will go on, indicating operation of unit.
8. Using voice, program material or tone generator
(such as Shure Model A15TG) for input to sound
system, increase console or mixer output level until
SR107 OVERLOAD lndicator (4) flickers. Increase
volume control on power amplifier until amplifier
clipping distortion is evident. OVERLOAD lndicator
now indicates onset of clipping in both SR107 and
power amplifier. NOTE: This step does not apply
to Link operation.
9. Using voice or program material as source, adjust
console or mixer output to provide desired sound
level in room. (For Link use, adjust individual chan-
nel volume controls for desired mix and set to level
that will cause only occasional flickering of SR107
OVERLOAD lndicator on peaks of high level pro-
gram material.) If microphones are used as sound
source, satisfactory sound level may not be possible
due to feedback. In this case, set volume to stable
point just below feedback level.
10. Operation of SR107 such that OVERLOAD lndicator
flickers slightly, on only the loudest program peaks,
is recommended. This will maximize signal-to-noise
ratio, but will generally not result in audible distor-
tion since lndicator threshold is 3 dB below actual
clipping level.
Operating with OVERLOAD lndicator always off may
result in less than optimum signal-to-noise per-
formance.
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