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3 RB-PMX4 10 Input, 4 Output Analogue Preset Mixer
Introduction
Fig 3-1: RB-PMX4 Front Panel .
The RB-PMX4 is a high performance 10 mono input to 4 mono output preset mixer. Each of
the four outputs has a 10 way DIP switch associated with it to select which of the 10 inputs
are routed to it. So, by altering the DIP switches, any of the input sources can be mixed to
any of the outputs. The DIP switches are enclosed by a screw-on cover on the front panel so
that the settings can not be accidentally changed for secure applications.
The RB-PMX4 has been designed for situations where a small mixer is needed for
installations where it will be configured and then only altered occasionally, or never altered.
Uses for this product are numerous including a four bus mini-mixer, a 4 zone mixer for pubs
and clubs, a multiple clean-feed generator and a quad stereo to mono converter to name
a few.
The XLR-3 inputs and outputs are electronically balanced and can be wired unbalanced.
Each output is individually buffered so that a short circuit on one won’t affect the others.
Each input has its own gain control which is a pre-set potentiometer accessible through the
front panel. This provides gain adjustment of -8dB to 18db. This is useful for normalizing
consumer and professional signals to give outputs of -15dBu and 0dBu respectively.
The front panel is held on by 2 off M3 x 6 stainless steel dome-head screws and can be
removed using a 2mm AF hex key (allen key). Each 10-way switch represents an output and
the individual switches represent the inputs that will be mixed to that output. Switches are
in the ON (down) position to be mixed and the OFF (up) position for off.
The XLR-3 outputs are electronically balanced and can be wired unbalanced. Each output is
individually buffered so that a short circuit on one won’t affect the others.
An LED power indicator on the front panel displays the power supply connection.
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System Block Diagram
Fig 3-2: RB-PMX4 Block Diagram.
Rear Panel Connections and Operation
Fig 3-3: RB-PMX4 Rear Panel.
Gain
Gain
Gain
Gain
Gain
Gain
Gain
Gain
Gain
Gain
Balanced XLR
Input 1
Balanced XLR
Output 1
Output 1
Switch Bank
Output 2
Switch Bank
Output 3
Switch Bank
Output 4
Switch Bank
Balanced XLR
Output 2
Balanced XLR
Output 4
Balanced XLR
Output 3
Balanced XLR
Input 2
Balanced XLR
Input 3
Balanced XLR
Input 4
Balanced XLR
Input 5
Balanced XLR
Input 6
Balanced XLR
Input 7
Balanced XLR
Input 8
Balanced XLR
Input 9
Balanced XLR
Input 10
Inputs Outputs
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Inputs 1-10
The XLR-3 input sockets can take balanced professional levels, or unbalanced by using the
front panel gain controls, and by connecting the non-phase to the signal ground screen. The
XLR 3 pin input has the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
Outputs 1-4
The XLR 3 pin output plugs are electronically balanced, and can be wired unbalanced. Each
output is individually buffered so that a short circuit on one output will not affect the others.
They have the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
Front Panel Controls
Fig 3-4: RB-PMX4 Front Panel Controls.
Switch Banks
There are 4 off 10-way switch banks, one for each output. Using these switches, each
input channel can be individually selected to each output. When the switches are up (OFF)
position, they are off and mixed when in the down (ON) position.
Input Gain Controls
The gain for each input may be individually varied from –8dB to 18dB by adjusting
the pre-set potentiometers, which are accessible through the holes in the front panel.
This is useful for normalising consumer and professional signals to give outputs of –15dBu
and 0dBu respectively.
INPUT LEVEL
1 2 10
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Input Gain Controls
Switch Banks
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Technical Specifications RB-PMX4
Audio Specifications
Maximum Input Level: +28dBu
Input Impedance: >20kΩ balanced bridging
Maximum Output Level: +28dBu
Output Impedance: <50Ω
Frequency Response: 20Hz to 20kHz ±0.1dBu (600 Ω load, @ 1kHz)
Input Gain Range: Adjustable 8dBu loss to 18dBu gain.
Common Mode Rejection: >60dBu typically
Off-isolation/Crosstalk: >90dBu @ 1kHz
Noise: -86dBu RMS 22Hz-22kHz, unity gain, ref +8dB
Distortion: <0.01% @ 1kHz, 0dBu to +26dBu
Connections
Inputs: 10 x XLR 3 pin female (Balanced, can be unbalanced)
Outputs: 4 x XLR 3 pin male (Balanced, can be unbalanced)
Mains Input: Filtered IEC, 110V-120V, or 220-240V switchable, fused,
6W maximum
Equipment Type
RB-PMX4: 10 input, 4 output analogue preset mixer
Physical Specifications
Dimensions (Raw): 48cm (W) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed): 53cm (W) x 20.5cm (D) x 6cm
Weight: Nett: 1.5kg Gross: 2.2kg
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