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Operating Instructions
Contents of the box:
Mixer/Amplier AMV-7240
19" rack mount brackets (pre attached)
IEC Mains Cable
AMV-7240
Automatic-Mixer/Amplifier
unit size: 430 mm x 335 mm x 88 mm (without rack mount brackets)
weight: 10.15 kg net, 12.7 kg shipping
After unpacking the unit connect the delivered power cable (IEC plug) with the receptacle on the rear side of the
unit. Before connecting the other end of the power cable to the wall outlet, make sure that the „POWER“-switch
on the right hand side on the front of the unit is in the „OFF“ position. Also the MASTER VOLUME rotary knob
should be set to „min“ (fully counterclockwise).
Controls
Front side:
On the left hand side you will nd ve rotary knobs for setting the level of the microphone and line level inputs.
In basic function the microphone inputs are set for mic level and the phantom power is set for electret-/condensor microphones, requiring 48 volts phantom powering.
The microphone and line level inputs are set to automatic function, opening only at a predetermined SPL, veried
by the green LED indicator „ACTIVE“. The automatic function can be disabled (using a thin pin tool) “AUTO OFF“.
In the basic settings this switch is pushed in and the automatic function is active. The red LED indicator above
veries the onset of the limiter function (LIMIT). The limiter circuit avoids overload and clipping of the signal.
In the mid section of the front panel you will see the switches- and controls for the AUX inputs, used for connec-
tion of CD-/MP3 player, wireless microphones etc. The AUX inputs are located on the rear of the unit (twin RCA
inputs) and are internally set to mono/parallel. The required AUX input is selected from the front panel (either
AUX-1 or AUX-2). Here you also set the level and the desired high-/low EQ of the signal.
On the right hand side on the front panel you will nd the main level control with metering and indication of
limiter activity and of course the on/o switch with control indicator.
Rear side of the unit –> next page…
Rear side (from left to right):
IEC mains socket with fuse holder. Fuse is 4 A, slow blow. In case this fuse will blow (green LED indicator on the
front is o) pls. exchange the fuse with a new one of the same type. In the rare case the fuse should blow again,
please contact a service technician or your dealer.
Right hand from the mains socket you will see the touch proof binding post connectors (red and black) for the
loudspeakers. On the right side of the rear panel are located all audio connectors: The RCA type connectors
for AUX-1 and AUX-2, which are selected with switches on the front side. Below are the ve “combo” inputs for
microphone or line level, via 3 pin XLR or 3/8” TRS phone plugs.
Above you will see the „PARALLEL“ input- and output connectors. These are 5-pin. XLR connectors, servicing as
loop inserts for external eect units (FX) or to connect another AMV-7240 for increasing the number of inputs or
doubling the output power. A further twin RCA connector is intended to record the summed signal. The 3-pin
XLR is used to hook up additional ampliers.
Important!
The model AMV-7240 is preset to basic functions as standard. Other or additional functions must be set internally,
which due to safety reasons should only be performed by a qualied service technician. The possible internal
settings include:
• 3-band equalizer for each input
• Threshold for the automatic mixing function (gate)
• Limiter settings for each input
• Gain settings for each input
• Compressor settings for each input
• Disabling of the total 48 volts phantom powering
• 4 parametric lter settings incl. Q, centre frequency and gain
• Total bypass switch for the parametric lters
• Ducking (attenuation) of the AUX signal by the microphone signals
Setting of the amplier to low impedance or 50/70/100 V operation: In the factory settings the
amplier is intended for 100 V constant voltage operation. The change to low impedance or 50/70 V operation
is done via cable taps.
The following pages will give you some more detailed information on the various internal settings.
Important again: All internal settings/changes should be performed by qualied technicians due to the fact
that the case cover must be removed and that danger regarding electrical shocks exists.
The AMV-7240 is delivered from factory with with pre-mounted 19” brackets. These may be removed for table-
top operation.
Enjoy an excellent sound and a long time, trouble free operation with your AMV-7240.
In any respect all technical data and components meet highest standards.
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AMV-7240
Automatic-Mixer/Amplifier
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1. Basic settings of the amplier (level/microphone input sensitivity)
Set the rotary knob VOLUME in the master section on the front panel to 4. Open the bridge jumper
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J14, AUTO ON on the basic printed circuit board (PCB) – this disables the automatic mixing function.
Set the level of MIC/LINE 1 on the front panel to max and the other inputs (2 - 5) to min.
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Adjust the microphone input sensitivity with the trimmer GAIN on the PCB, so that you obtain maximum
sensitivity (gain) before acoustical feedback occurs.
Set the microphone equalizer HIGH, MID, LOW (trimmer on PCB) to the required sound under consideration
of the microphone sound characteristic and room acoustics. If necessary adjust the level to insure a safety
margin before the onset of feedback.
Repeat the settings mentioned before for all inputs with connected microphones. To activate phantom
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powering for condenser microphones set the jumper PHAN on the PCB accordingly.
The trimmer COMPR (on the mic input PCB) allows for adjusting the threshold for onset of signal compression.
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The NOI SEGATE trimmer may be adjusted for the desired threshold of the gate (gain reduction of 10 dB).
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A subsonic lter (high pass) may be activated with the jumper SUBBASS ON (for example to improve
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intelligibility of speech in a noisy surrounding).
The microphone inputs may also be used as link inputs. Deactivating of automatic mixing and compression
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is done by depressing MIX OFF for the corresponding input on the front panel.
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2. Setting/adjusting automatic mixing
Set the trimmer J14, AUTO ON, MIX GATE fully counterclockwise and all microphone inputs to max. Rotate the
•
trimmer carefully and slowly clockwise to the point that no word of the speech is lost and the corresponding
microphone opens immediately when the speaker starts talking. When speaking to one of the microphones
(green LED ACTIVE) all other microphones should not be activated by the acoustic surrounding. Activated
microphones are recognized by the corresponding green LED. For most applications the centre setting of
the trimmer is a good point to start.
3. Setting/adjusting volume
In normal operation the MIC/LINE potentiometers are set to maximum. Unused inputs are set to minimum.
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For these inputs the MIX OFF switch should be activated in order not to inuence automatic mixing. The overall
volume is set with the rotary potentiometer VOLUME. Carefully observe onset of acoustical feedback.
In venues with high sound reections (poorly damped) start with a setting of the knob to position 4. In instal-
lations with improved (higher damped) acoustical conditions the total useable volume may be increased –
but again: watch the danger of acoustical feedback.
Non authorized persons should not have access to the internal settings.
4. AUX settings
Choose the input signal AUX 1 or AUX 2 by depressing the equivalent push button on the front panel (section AUX
CONTROL). The trimmers GAIN AUX lets you set the sensitivity so, that no limiting of the signal occurs (VOLUME 4),
veried by the LIMIT LED in the master section. Set the desired volume with the rotary knob VOLUME (on the front
panel in the section AUX CONTROL). The sound (tonal characteristics) can be set and optimised by the potentio meters LOW and High accordingly.
5. Ducking (automatic signal attenuation)
Connect the signal to the AUX input and set the trimmer DUCK AMPL to centre position. Now test this function by
speaking into the microphone at the MIC/LINE input. The DUCK GATE threshold may be adjusted at the same named
Trimmer, so that the AUX signal is attenuated to your preference.
6. Parametric equalizer
The parametric equalizer is helpful for solving problems in venues with dicult acoustic environment and to simulta niously optimise speech for maximum intelligibility. Feedback prone frequencies lowering the threshold for onset of
feedback are ltered out of the audio spectrum (reected signals are time delayed). The EQ is simply activated by
EQ ON.
The built in equalizer covers the total audio spectrum. For ease of use the EQ is split into 4 overlapping sections: F1
= 20…9 000 Hz, F2 = 65…3 000 Hz, F3 = 170…7 000 Hz and F4 = 450…20 000 Hz. The (critical) frequency is selected
by the trimmer FREQ, the bandwidth Q = 1…12 with the trimmer BAND and the amplitude range with the trimmer
GAIN. The sections are overlapping in order to lter out a relative small and steep frequency range (notch-lter).
7. Amplier output level
When setting up the system in venues with high acoustical damping factor, where high output power can be utilized,
set the rotary pot VOLUME in the MASTER area on the front panel so, that no permanent limiting of the output signal
occur (watch the LIMIT LED, which also can indicate amplier overload).
Other amplier functions
• Microphone signals may be recorded at the RECORD outputs, without being inuenced by the volume setting.
Parallel operation of 2 ampliers is also possible in the AUTOMATIC Mixing mode. In this case the PARALLEL
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connectors of both amps are used for both ampliers. The input of amplier 1 with the output of amplier 2
and vice versa.
An external eect device (FX), such as Echo, may be looped into the signal path of the amplier via the parallel
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connectors between INPUT and OUTPUT .
An additional power amplier may be connected to the output of the AMV-7240. The kind of signal proces-
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sing in our mixer/amplier is determined by the jumper OUTPUT. In position EQ the signal is routed through
the equalizer and the setting for the total gain. In the position VOL the signal is routed through the sum level
control but not through the EQ. In the SUM position the signal will neither be routed through any of the be
fore mentioned sections.
9. Output power
Output power is available at the transformer taps 100 V, 75 V and 50 V.
The choice of the amplier conguration is done by switching taps on the output transformer.
Details of the controls on the PCBs see next page.
• It is possible to record MIC signals on RECORD outputs without affecting it by
volume regulators
• Parallel operation of 2 amplifiers is also possible in automatic mixing mode. Then
PARALLEL connectors of both amplifiers are connected so that the input of the
first one is connected with the output of the second one and vice versa.
• An external device (e.g. echo) can be connected into signal path of the amplifier
through PARALLEL connectors between INPUT and OUTPUT. Input and
output are balanced.
• Another power amplifier can be connected on output of our amplifier. The way of
signal processing in our mixing amplifier is given by position of shorting jumper
OUTPUT.
In EQ position the signal goes through equalizer and summary regulator.
In VOL position the signal goes through summary regulator but not through
equalizer.
In SUM position the signal does not go through summary regulator nor equalizer.
9) Output power set-up:
Output terminals can be connected to taps of output transformer (100V, 75V, 50V)
or directly to 4 Ohms output.
noisegate compr low mid high gain
output
output
Pic. 2 Set-up components of basic PCB
limit
compr subbas
mix off
active
duck ampl gain aux duck gate mix gate auto on
GAIN BAND FREQ GAIN BAND FREQ GAIN BAND FREQ GAIN BAND FREQ
DECLARATION OF CONFORMITY
We declare as our sole re sponsibility that this produc t is in compliance with the EMC
Directi ve 89/336/EEC and confor ms to the requirements of the Harm onized Product
Standards EN 55013 (Product Emissio ns), and EN 55020 (Product Immunit y).
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axxent e.K. · Zum Wartturm 15 · 63571 Gelnhausen · Fon (06051) 91 40-0 · Fax 91 40-59
www.axxent.de · mail@axxent.de
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