Soundcraft SM24 USER GUIDE

SOUNDCRAFT

USER GUIDE

 Soundcraft Electronics Ltd. 1994

Parts of the design of this product may be protected by worldwide patents. Part No. ZM0057/02

Issue 2

Information in this manual is subject to change without notice and does not represent a commitment on the part of the vendor. Soundcraft Electronics Ltd. shall not be liable for any loss or damage whatsoever arisin g from the use of information or any error contained in this manual.

No part of this manual may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, electrical, mechanical, optical, chemical, including photocopying and rec ording, for any purp ose without the express written permission of Soundcraft Electronics Ltd.

It is recommended that all maintenance and service on the product should be carried out by Soundcraft Electronics Ltd. or its authorised agents. Soundcraft Electronics Ltd. cannot accept any liability whatsoever for any loss or damage caused by service, maintenance or repair by unauthorised personnel.

Soundcraft Electronics Ltd. Cranborne House Cranborne Industrial Estate Cranborne Road Potters Bar Herts. EN6 3JN England

Tel: 0707 665000 Fax: 0707 660482

Contents

Introduction 1

Introduction 2 Precautions and Safety Instructions 3

Installation 5

Wiring Considerations 6 Power Supply (CPS950) 6 Connections 7

Module Block Diagrams 9

Input Module 10 Group Output Module 11 Master Module 12

Input Module 13

Module Description & Operation 14

Output Module 21

Module Description and Operation 22

Master Module 29

Module Description & Operation 30

VCA Master Module 37

Module Description & Operation 38

Console Linking 39

Appendices 41

Specifications 42 Dimensions & Configurations 44 Warranty 45 Glossary 46

Introduction

Introduction 1

Intro du c tion

The SM24 has been designed in consultation with top engineers to provide the ultimate tool for onstage monitor mixing.

The key features of the SM24 are:

• A total of 26 busses reconfigure to provide almost any combination of mono

and stereo mixes

• Dedicated stereo send, for sidefills or main mix output in FOH applica tions

• 4 band parametric EQ plus variable High-Pass filter on all input channels

• Logic controlled solo system with autocancel, input priority and solo clear

functions

• Full audio and logic console linking

• VCA and Mute Masters offer a total of 16 mute groups

• All inputs and outputs fully balanced

• Channel Inserts and Direct Outputs are Ground Compensated as standard

Frame Sizes

Power Supplies

Lamps

The SM24 is available in 3 compact frame sizes:

• 32 channel

• 40 channel

• 48 channel

All frame sizes use the CPS1000 PSU. Connection to the console is via an 8-way and a 16-way SRC connector. The SRC panel also carries a ground binding post.

Three BNC connectors for lamps are fitted to all frame sizes - one on the master module, and one at either end of the console on the infill panels. The are suitable for Littlite or similar 12V lamps taking up to 330mA each. The voltage supply to the lamps can be varied between 1.5V (dim) and 12V (bright) by the dimmer control.

The console features rear COMM S LI NK conn ectors to allow a Clearcom sy stem to be looped through. When a ’call’ button is pressed on the Clearcom unit, the lamps are flashed to signal the engineer.

2 Introduction

Precautions and Safety Instructions

General Precautions

Caution!

Handling and Transport

Power Supplies & cables

Avoid storing or using the mixing console in conditions of excessive heat or cold, or in positions where it is likely to be subject to vibration, dust or moisture. Do not use any liquids to clean the fascia of the unit: a soft dry brush is ideal. Use only water or ethyl alcohol to clean the trim and scribble strips. Other solvents may c ause damage to paint or plastic parts.

Avoid using the console close to strong sources of electromagnetic radiation (e.g. video monitors, highpower electric cabling): this may cause degradation of the audio quality due to induced voltages in connecting leads and chassis. For the same reason, always site the power supply away from the unit.

In all cases, refer servicing to qualified personnel.

The console is supplied in a wooden crate. If it is necessary to move it any distance after installation it is recommended that this packing is used to protect it. Be sure to disconnect all cabling before moving. If the console is to be regula rly moved we recommend that it is installed in a foamlined flightcase. At all times avoid applying excessive force to any knobs, switches or connectors.

Always make sure that the power supply unit (PSU) has been set to the same voltage as the mains supply

Warning!

Always use the power supply and cable supplied with the mixer: the use of alternative supplies may cause damage and voids the warranty; the extension of power cables may result in malfunction of the mixing console.

Always switch the power supply off before connecting or disconnecting the mixer power cable, removing of installing modules, and servicing. In the event of an electrical storm, or large mains voltage fluctuations, immediately switch off the PSU and unplug from the mains.

Always ensure that you use the correct PSU for your mixer. The SM24 uses a CPS1000 power supply.

Introduction 3

Signal Levels

It is important to supply the correct input levels to the console, otherwise signal to noise ratio or distortion performance may be degraded; and in extreme cases, damage to the internal circuitry may result. Likewise, on all balanced inputs avoid sources with large common mode DC, AC or RF voltages, as these will reduc e the available signal range on the inputs. Note that 0dBu = 0.775V RMS.

The microphone inputs are designed for use with balanced low impedance (150 or 200 ohms) microphones.

Caution!

DO NOT use unbalanced microphones or battery powered condenser microphones without isolating the +48V phantom power: degraded performance or damage to the microphone may result.

The sensitivity of the XLR inputs is variable from -2dBu to -70dBu and +10dBu to

-20dBu in two ranges (for +4dBu at the Mix outputs). The maximum input level is +18dBu for the first range, and +30dBu for the second range.

The Hi-Z inputs have a sensitivity variable between +10dBu and -20dBu. The maximum input level is +30dBu.

The main outputs of the console (stereo mix, groups, wedge and mix and group insert sends) are balanced at a nominal level of +4dBu, with a maximum output level of +26dBu.

The input insert sends and direct outputs are ground co mpensated at a nominal level of -2dBu, with a maximum output level of +20dBu.

All external inputs and mix and group insert returns have a nominal level of + 4dBu, and a maximum input level of +26dBu.

Input insert returns have a nominal level of -2dBu, and a maximum input level of +20dBu.

4 Introduction

Installation

Installation 5

Ins tallation

The SM24 is designed for reliability and high performanc e, and is built to the highest standards. Whilst great care has been taken to ensure that installations are made as troublefree as possible, care taken at this stage, followed by correct setting up will be rewarded by a long life and reliable operation.

Wiring Considerations

Power Supply (CPS1000)

Warning!

A For optimum performance it is essential for the earthing system to be clean and noisefree, as all signals are referenced to this earth. A central point should be decided on for the main earth point, and all earths should be ’star-fed’ from this point. It is recommended that an individual earth wire be run from each electrical outlet, back to the system star point to provide a safety earth re ference for each piece of equipment.

B Install separate mains outlets for the audio equipment, and feed these independently from any other equipment.

C Avoid locating mains distribution boxes near audio equipment, espec ially ta pe recorders, which are very sensitive to electroma gn etic field s.

D Where possible ensure that all audio cable screens and signal earths are connected to ground only at their source.

Always ensure that you use the correct PSU for your mixer. The SM24 uses a CPS1000 power supply.

Before switching on your SM24 console, check that the mains voltage selectors on the power supply unit is set to the correct mains voltage for your area, and that the fuse is of the correct rating and type. This is clearly marked on the case of the power supply. Do not replace the fuse with any other type, as this could become a safety hazard and will void the warranty.

6 Installation

C onnections

Wiring conventions

MICROPHONE INPUTS

TALKBACK INPUTS

EXTERNAL RETURNS

The SM24 uses two different types of audio connec tor: 3-pin XL R a nd jacks. The latter are used in several configurations, as shown below.

MIX L, R & WEDGE OUTPUTS

GROUP & TB OUTPUTS

/4" ‘A’ Gauge Stereo Jack Plug used as balanced input:

Line inputs, insert returns

AFL & PFL OUTPUTS

⁄

" 3-pole

/4" ‘A’ Gauge Stereo Jack Plug used as ground compensated output:

Input insert sends, Input direct outputs

/4" ‘A’ Gauge Stereo Jack Plug used as balanced output:

Mix insert sends, Group insert sends

/4" ‘A’ Gauge Stereo Jack Plug used as stereo output: Headphones

Installation 7

8 Installation

Module Block Diagrams

Module Block Diagrams 9

+48V

Input Module

INPUT

HI - Z

INPUT

INSERT

SEND

INSERT

RETURN

DIRECT

OUT

MUTE/VCA BUSSES

MUTE

VCA

VCA IS BYPASSED WHEN CHANNEL

NOTE:

IS NOT ASSIGNED TO VCA GROUPS

OPTION

MUTE

LOGIC

VCA

LOGIC

SENS

INSERT

PREEQPRE

MUTE

METER

MUTE

GRP 1 - 8

PRE-FADE

SOURCE

FILTER

HI-PASS FILTER

SEND

PEAK

VCA

PRE FADE

RET

FADER

INSERT

PRE EQ

POST FADE

LO MID

L/R SEND PRE-FADE SOURCE

1 A

1 B

11A

11B

HI MID

L/R

GRP 9 - 16 PRE-FADE SOURCE

STEREO

PAN

PFL BUS

GROUP 1 - 24 BUSSES

R STEREO BUS

L STEREO BUS

INSERT

POST EQ

CLEAR

R L

13A

13B

14A

STEREO

14B

15A

STEREO

15B

STEREO

12A

12B

STEREO

16A

16B

STEREO

10 Module Block Diagrams

R AFL BUS

L AFL BUS

PFL BUS

GROUP 1 - 8 BUS

GROUP 9 - 16 BUS

R STEREO BUS

L STEREO BUS

Group Output Module

CLEAR

SUMMING

AMP

SUMMING

AMP

FADER

CLEAR

STEREO

FADER

AFL

TRIM

AFL

TRIM

INSERT

INSERT INSERT

INSERT

EBOS

VOL

TB/OSC

METER

EBOS

CLEAR

EXT

GROUP

OUT

INSERT

SEND

INSERT

RETURN

EXT VOL

TB/OSC

LEFT HAND

METER

MONO GROUP

STEREO GROUP

EBOS

EXT IN

GROUP

OUTPUT

SUMMING

AMP

EBOS

RETURN B RETURN A

SEND B SEND A

EBOS

RIGHT HAND

METER

UPPER SECTIONS OF GROUP MODULE

NOTE:

MAY BE CONFIGURED AS TWO MONO OR ONE STEREO GROUP

GROUP

OUTPUT

Module Block Diagrams 11

+ 35 hidden pages