4 Channel 1:4 Active Unity Gain Mic Splitter OPERATION MANUAL Version 3 November 2004
MS424 2
CONTENTS 1. INTRODUCTION 3 2. TECHNICAL SPECIFICATIONS 4 3. INSTALLATION 4 3.1 3.2 3.3 3.4 3.5 3.6 5 5 5 5 6 7 4. WARRANTY 8 5. DESCRIPTION OF CONTROLS 9 6. OPTIONS 10 Configuration Channel jumpers Bus jumpers Transformer balanced inputs 10 10 13 14 APPLICATIONS 15 7.
1. INTRODUCTION The MS424 is a 4 channel 1 into 4 Unity Gain Active Microphone Splitter in a compact 1U self powered case. The MS424 is designed for applications where multiple feeds are required from one set of microphones without the signal degradation experienced with most passive splitting solutions. The Unity Gain design philosophy allows simple integration into existing systems without the need for lengthy re-calibration.
2. TECHNICAL SPECIFICATIONS 2.1 ELECTRICAL 20 Hz to 20 kHz, +0, -0.5 dB Frequency response:: 2 kΩ Input Impedance:: 0 dBu (+20 dBu with Pad) Maximum Input Level: Equivalent Input Noise (EIN): better than -121 dBu less than 50 Ω Output Source Impedance: 150 Ω to infinity Output Load Impedance: 0 dB (-20dB with Pad) Gain: better than 0.01 % (1kHz, 150 Ω load) Total Harmonic Distortion (THD): Intermodulation Distortion: better than 0.
3. INSTALLATION 3.1 INSPECTION AND UNPACKING The MS424 has been carefully packed at our factory in a carton designed to withstand handling in transit. Should the unit appear to have been damaged in transit, notify your dealer immediately and do not discard any of the packing. The carton should contain • • • The MS424 Power cord - country specific, please check Operator Manual (this book) 3.
The rating of the rear panel fuse is as follows 230V T100mA 115V T200mA Both are slow blow type Please note: If the fuse requires changing at any time please ensure the correct type is fitted. An incorrect fuse could cause damage to the unit and may constitute a fire hazard.
capacitor to Chassis ground. This configuration prevents ground loop hum and ensures a low impedance path for RF (Radio Interference) away from the audio. Although the inputs are designed for 'balanced' signals either pin 2 or 3 can be connected to pin 1 for unbalanced operation. All outputs on the MS424 are balanced on male XLR type connectors. These are wired as follows XLR-M Pin 1 Pin 2 Pin 3 * Screen Hot (+ve) Cold (-ve) * Pin 1 is ground lifted - see above.
4. WARRANTY Your MS424 has been manufactured to a high standard using quality components. If correctly installed and operated the unit should give years of problem free operation. However in the event of a defect in material or workmanship causing failure of the unit within one year of the date of original purchase we will agree to repair, or at our discretion, replace any defective item without charge for labour or parts.
5. DESCRIPTION OF CONTROLS Phantom switch Switches +48V from the internal power supply to the Input connector on the rear panel. To prevent the chance of damage to any external pieces of equipment, do not use the +48V power option with unbalanced input sources i.e. those where pins 1 & 3 or 1&2 are connected together. To avoid loud and potentially damaging electrical noise always turn down monitor speakers and connect your microphone before switching phantom power on.
OUTPUT 2 connector Transformer balanced and isolated output. 6. OPTIONS 6.1 CONFIGURATION Each channel of the MS424 consists an input stage and an output stage.
The channel Input stage is connected directly to it's associated output stage. This provides 1 input to 4 output splitting and is the Factory default setting. MASTER The channel Input and output stage are connected to the internal bus. The Input signal is thus distributed to other output stages which have been configured as slaves. SLAVE The channel Input is disabled and it's output connected to the internal bus. The output stage now outputs signal from the internal bus.
Block diagram of the MS424 showing the channel and bus option jumpers. Channel Input to Output 1 LINK switching not shown - see diagram on following page. Only one Input stage at a time should be connected to the Internal Bus (Master mode) 6.3 INTERNAL BUS JUMPERS There are also two jumpers associated with the Internal Bus and determine the number of split outputs available.
6.4 TRANSFORMER BALANCED INPUTS Transformer balanced inputs can be fitted to provide galvanic isolation between inputs and outputs. Although normally a factory build option, transformers can be retro fitted by an Audient service centre.
7.0 APPLICATIONS The MS424 is primarily designed to be used in theatres, fixed installations or touring companies who require split feeds of the same signal. The active design of the MS424 ensures that there is not loading or signal loss and as each output is independent a fault on one will not affect the others. The Inputs and Outputs 1 & 2 have been sited on the rear panel so that for a typical installation using FOH (Front-of-House) and monitor consoles all connections are made to the rear of the unit.
