ADJ American Audio XEQ-152B User manual
2
General
Two channel 15 2/3 octave band graphic equalizer with frequency control of 25Hz to 16KHz. Is a
incorporates constant Q circuitry with a 3% center frequency accuracy. Special features include
selectable range 6dB or 12dB, active balanced and unbalanced input/output connectors, RFI
filters, variable level control, passive bypass switch, overload threshold LED, ground lift switch
and selectable line voltage switch.
Installation
Equalizers are designed for mounting in a standard 19" equipment rack or one of the many rack
type portable cases available on the market. The vertical space is 1.75 inches (44,5mm). The
XEQ-152B has 8.5inches (216mm) in depth.
Power connectors
The XEQ-152B integrates an IEC Connector to operate at 120/50Hz or 240 volt/50Hz. Before
use, check the slide switch to match your line voltage supply. CAUTION: To new installations and
portable sound systems, or any situation in which the mains power is suspect, it is wise to confirm
appropriate voltage and line polarity BEFORE connecting the instrument to power source.
DO NOT REMOVE THE CENTER GROUNDING PIN; In new installations and portable sound
systems, or any situation in which the mains power is in question, it is wise to confirm the voltage
and select the appropriate line voltage switch BEFORE connecting the instrument to power
sources.
Input Output Connections
The XEQ-152B graphic equalizer has three paralleled input and output connectors. XLR and 1/4
TRS are actively balanced with Pin 2 or the tip being Hi, Pin 3 or the ring being Lo, and Pin 1 or
sleeve being ground. Unbalanced operation requires using the RCA phono connector or use Pin
2 of the XLR or tip 1/4" TRS as Hi(+) and Pin 1 of the XLR or sleeve of the 1/4" TRS as ground.
Balanced output requires using Pin 2 of the XLR or the tip of the 1/4" TRS as output Hi ( +) and
using pin 3 of the XLR or the ring of the 1/4" TRS as Lo(-).It does not require pin 1 or signal
ground. The signal exists differentially between the two balanced leads. Ground is used only for
shielding to prevent potential hum.
Signal levels
Signal levels from -10 dBu to +4 dBu are considered normal and at least 20dB of headroom exists
above these levels. Do not directly connect microphones into the equalizer. Microphones require
a pre-amp.
Chassis Grounding
The equalizer is equipped with a rear panel Ground lift switch. After setting up your system and
the system exhibits excessive hum or buzzing, the problem is that there is a ground incompatibility
between your equalizer and other equipment in the same system. There are several combinations
that can be attempted. Note: ALWAYS TURN YOUR AMPLIFIERS DOWN BEFORE
CHANGING YOUR GROUNDS AROUND.
Try different combinations of lifting grounds on units that are supplied with ground lift switches or
make sure all chassis are connected to earth ground, either through the A.C. power cord ground
or by the front panel rack mount screws.
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Operating Instructions
Before starting to equalize your sound system there is some information you should know and
procedures you should follow. The XEQ-152B is equipped with a bypass switch with a LED
indicator. The bypass switch, when activated, the LED is on and cancels all equalization settings,
signal flows through at unity gain. Also included is a range selection switch with LED indicators,
6dB = green, 12dB= yellow. In conjunction to the range selection switch there is a level control
potentiometer. The level control operates between off and +6dB. Note: If there is too much gain
your equalizer has a red overload LED. The overload LED illuminates when signal reaches 5dB
prior to clipping. If this situation occurs and the overload LED flashes occasionally, this is okay,
but if the overload LED is steadily on you must re-adjust the level control. Below are some tips
while doing the initial set up.
1. Set channel levels to the center detent 0dB on the front panel.
2. Select the bypass switch (Note: The RED LED is ON.)
3. All slide controls to the center detent or 0dB.
4. Select the 6dB range switch (green LED on).
5. Apply signal to the system.
6. Release the bypass switch, red LED off.
7. If the OL (overload) LED is on you must turn down the level control.
8. You may now start equalizing your system.
9. If you are not receiving enough gain out of your equalizer switch the range switch to 12dB
(yellow LED will light).
10.Note: If the OL (overload) LED illuminates steadily turn down the level control until the LED is
off. Note: After you have the proper settings and you do not want it to betampered with, a security
cover may be purchased at a local international dealer for your convenience.
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Front Panel Controls
DUAL 15 BAND GRAPHIC EQUALIZER
1.Power Switch
To turn the equalizer ON or OFF, press the upper or lower portion of this button.
CAUTION: Always turn on your equalizer BEFORE your power amplifiers are turned on, and
always turn off your equalizer AFTER your power amplifiers have been turned off.
2.Filter Level Controls
Each of these sliders control the output level of each of the 15 bandpass filters. Center detent
position is grounded for guaranteed flat response.
3.Filter Range Switch & Indicators
The gain range of the filter sliders is switchable (as a group)from+/- 6dB to +/- 12dBformaximum
boost/cut capability. At 6dB the green LED will illuminate and at 12dB the yellow LED will
illuminate.
4.Bypass Switch & Indicator
When the red LED is illuminated, this indicatesthat the unit or channel is the bypass mode. Signal
is routed directly from the input to the output without passing through any circuit (often referred to
as "hard-wire bypass"). Use this switch to compare equalized and unequalized material, or to
bypass the EQ section in the event of power loss or unit failure.
5.0verload Indicator
This red LED illuminates if any section of the equalizer is within 5dB of clipping. Occasional
blinking of this LED is acceptable, but if it remains on more than intermittently you should turn
down either the equalizer's level controls or reduce the output level of the preceding component
to avoid audible distortion.
8.Level Control
This controls the level of signal coming into the instrument. Turn this control down if the
OVERLOAD LED illuminates steadily (meaning too strong on input signal). Unity gain can be set
by turning this knob to its center detent position.
5
Rear Panel Connectors & Controls
DUAL 15 BAND GRAPHIC EQUALIZER
9.IEC Socket
This cord is used connect the AC power source your equalizer. CAUTION: Equipment for USA
consumption includes a captive power cord with a three-pin polarized plug. DO NOT REMOVE
THE CENTER GROUNDING PIN.
This IEC Socket contains an AC primary fuse. This fuse should be replaced by the same type of
fuse when this is blown out. If they continuously blow, stop replacing fuse and refer servicing to
qualified personnel. CAUTION: After checking the AC supply voltage, be sure that the correct
fuse is used; 0.5 Amp for 100-120V AC as well for 220-240V AC.
10.AC Voltage Selector (only for EQ of AC power supply)
Set this slide switch to match your line voltage supply. CAUTION: To new installations and
portable sound systems, or any situation in which the mains power is suspect, it is wise to confirm
appropriate voltage and line polarity BEFORE connecting the instrument to power source.
11.Ground-Lift Switch
This switch is used to disconnect the signal ground from the mains and chassis earth ground.
User is suggested to put the switch to LIFT position if "HUM", caused by ground-loop, can be
heard at the speakers.
12.Input/Output Connectors
1/4 "TRS
The TRS (Tip Ring Sleeve) connector is balanced and wired as tip = Hi(+), Ring = Lo(-), and the
Sleeve = Ground.
CAUTION: Only one of these sockets can be chosen for audio connection at the same time.
XLR
The XLR input connector is balanced and wired as Pin 2 = Hi( +),Pin 3 = Lo(-), Pin 1 = Ground.
CAUTION: Only one of these sockets can be chosen for audio connection at the same time.
RCA Phono
The RCA Phono input is unbalanced at the tip = Hi(+) and the Sleeve = Ground.
CAUTION: Only one of these sockets can be chosen for audio connection at the same time.
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