LA Audio MPX10 User Manual

MULTI PROCESSOR

OPERATION MANUAL

Version - V1 April 2000

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CONTENTS

Page

1. Introduction

2. Installation

3 4

2.1 Inspection and un-packing 4

2.2 Operating environment 4

2.3 CE standards 4

2.4 Power requirements 4

2.5 Signal levels 5

2.6 External connections 6

3. Warranty

4. Description of controls

9 10-15

4.1 Input section 10

4.2 Noise Reduction and Compressor section 11

4.3 Equaliser section 13

4.4 Output section

5. Applications

16-21

5.1 Input 16

5.2 Compressor 16

5.3 Expander 18

5.4 Equaliser 18

5.5 Output 20

6. Circuit description

6.1 Inputs 22

6.2 Expander and Compressor 22

6.3 Output 23

7. Specifications

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1.0 INTRODUCTION

The MPX10 is a single channel processor designed for one step processing of vocal or solo instruments where the highest quality signal path is required. The MPX10 combines a Mic/Line preamplifier with DI input, Noise Reduction, 4 mode Auto Compressor and Equaliser in a compact 1U case.

The MPX10 is an ideal front end for direct to tape or hard disk recorders and as a superior analogue input stage for digital work stations. The MPX10 is equally at home in sound reinforcement applications where it can provide feedback suppression, vocal levelling and comprehensive tone shaping.

Features include -

• Balanced Line and Microphone inputs (with +48V phantom power)

• High impedance (0.5M) DI input

• High and low pass filtering

• Downward expander Noise Reduction

• Auto Compressor with variable Threshold, Ratio and Gain

• In-built De-ess function

• HF and LF shelving EQ

• 2 parametric mid range sections with Ga in, Frequency and Q controls

• Output level adjust

• Gain Reduction and Output metering

• Ground compensated outputs at +4dBu and -10dBV

• Input and output break jacks for the Input, Compressor, EQ and output sections

This last feature allows the user to re-configure the MPX10's signal path such as putting the EQ before the Compressor. It also means that the MPX10 can be used as 4 separate signal processors -

• High quality, low noise Mic, Line, DI preamplifier

• Downward expander and auto Attack/Re lease compressor

• 4 band Equaliser

• Variable gain line driver with level metering

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2.0 INSTALLATION

IMPORTANT: PLEASE READ THIS SECTION BEFORE USING THE MPX10

2.1 INSPECTION AND UNPACKING

The MPX10 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 MPX10 unit

• Power cord

• Operator Manual (this book)

2.2 OPERATING ENVIRONMENT

The MPX10 is designed to operate between 0 and 50°C (32-122°F) with relative humidity no more than 80%. Should the unit be installed in an equipment rack, ensure that the ambient temperature conforms to these levels.

2.3 CE STANDARDS AND THE LOW VOLTAGE DIRECTIVE (LVD)

The MPX10 has been designed to meet the latest Electromagnetic Compatibility (EMC) regulations. However we recommend you do not operate the unit close to strong emitters of electromagnetic radiation such as power transformers, motors, mobile telephones or radio transmitters.

The unit should only be connected to a power supply of the type described in 2.4 POWER REQUIREMENTS or as marked on the unit. The unit must be earthed for safe operation. Disconnect the mains supply before removing any cover.

2.4 POWER REQUIREMENTS

There is a mains fuse located inside the unit which is accessed by removing the cover. This fuse is for protection against unit faults and as such will not normally need replacing. If you think you have a power related problem please refer to your dealer.

The voltage and fuse rating have been factory set for 230V 50mA UK and Europe

220V 100mA Republic of Korea

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110V 100mA North America

• The correct voltage and fuse rating is indicated on the

rear panel.

• Please check that your unit is correctly rated for the

voltage of the country of operation.

If the fuse requires changing at any time please ensure the correct fuse is fitted. An incorrect fuse could cause damage to the unit and may constitute a fire hazard.

If you carry your MPX10 from one country to another it is very important to ensure the voltage is compatible.

For your information the unit can be internally rewired for use in 230V, or 110-125V countries - contact your dealer for information. A special 100V version is available for Japan and a 220V version for Republic of Korea.

The mains lead connections to the appliance are coloured in accordance with the following code:

•

WARNING: THIS APPLIANCE MUST BE EARTHED

2.5 SIGNAL LEVELS

For input level ranges see GAIN control in the Description of Controls section.

The MPX10 outputs both -10dBV and +4dBu operating levels without the need for level switching.

IMPORTANT NOTE:

for -10dBV operating levels. Use the appropriate connector/level to interface between your equipment and the MPX10.

The OUTPUT control on the MPX10 allows -20dB to +20dB of level adjustment which should allow the MPX10 to interface to most equipment types.

Green-and-Yellow Earth Blue Neutral Brown Live

the XLRs are set for +4dBu and the TRS jacks

Signals in excess of +20dB will cause the unit to distort.

2.6 EXTERNAL CONNECTIONS

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INPUT SECTION:

MICROPHONE

XLR Pin 1 Screen (Signal

ground)

Pin 2 Hot (+ve) Pin 3 Cold (-ve)

This is a low impedance (1.2k), low level input designed to give the correct loading and sensitivity for dynamic type microphones. Plugging line sources into this input may load the connected equipment and may result in the loss of signal level, frequency range and increased distortion.

PUSH

Pin 1 = ScreenPin 2 = Hot (+)

Pin 3 = Cold (-)

Microphone Input XLR connections (view of connector on MLX2)

LINE

TRS Tip Hot (signal +)

Ring Cold (signal -) SleeveScreen (signal ground)

Sleeve Screen

R ing

Cold (-)

Tip

Hot (+)

Fig 2.6.3: Line Input and -10dBV Output connections

The 20k input impedance of the LINE input is suitable for most types of equipment.

For un-balanced operation join Ring and Sleeve on your connecting cable.

Plugging a mono jack lead into the LINE input will effectively un-balance the signal connection.

jack Tip Hot (signal +)

SleeveScreen (signal ground)

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Sleeve Screen

Tip

Hot (+)

Fig 2.6.4: DI Input connections This a high impedance (0.5M) input primarily intended for connecting

directly to electric guitars.

OUTPUT

jack Tip Hot (signal +)

SleeveScreen (signal ground)

This connector provides an unbalanced line level output from the Mic/Line/DI preamplifier. Plugging a jack into this connector does not effect the signal path through the MPX10. Source impedance is 100 which is suitable for driving loads of 1k and greater.

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COMPRESSOR SECTION

INPUT

jack Tip Hot (signal +)

SleeveScreen (signal ground)

This is the input to the Compressor section and is normally connected to the 'output' of the Mic/Line/DI preamplifier. Plugging a jack into this connector breaks the signal path and the Tip of the inserted jack becomes the input to the compressor (Half-Normalled). All the 'Input' and 'Output' connectors between each of the processing sections on the MPX10 work in this way.

'Input' is unbalanced, however the connector is wired in such a way as to be compatible with un-balanced (mono) and balanced (stereo/TRS) jacks.

SIDECHAIN

jack Tip Return

Ring Send SleeveScreen (signal ground)

Sleeve Screen

R ing

Send

Tip

Return

Plugging into the MPX10's side chain automatically breaks the signal path to the side chain circuitry. This path must be completed by the external connected equipment.

The side chain in-out signal path affects both the Compressor and the Expander response.

Commonly used to insert an equaliser into the sidechain to produce frequency conscious compression such as de-essing.

Because each section of the MPX10 has Input and Output break jacks it is possible to plug the EQ of the MPX10 into the Compressor sidechain to allow more advanced Frequency Conscious Compression.

LINK

jack Tip Control voltage

SleeveScreen (Control voltage

ground)

Link provides a means of joining the sidechain detectors of two MPX10s for stereo operation. To ensure accurate stereo tracking the NR and Compressor controls on both MPX10s should be set the same. Linking and setting-up MPX10s in this way also ensures that signals from either MPX10 cause compression.

Please note that the Link output is a DC control voltage and should not be connected into any audio signal path.

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OUTPUT

jack Tip Hot (signal +)

SleeveScreen (signal ground)

An unbalanced output from the Compressor section.

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