SoundCraft SM12 User manual

SOUNDCRAFT
USER GUIDE
12

 Soundcraft Electronics Ltd. 1994
All rights reserved
Parts of the design of this product may be protected by worldwide patents.
Part No. ZM0075-01
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 arising 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 recording, for any purpose
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: [phone]
Fax: [phone]

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Introduction 1
Introduction 2
Precautions and Safety Instructions 4
Installation 7
Connections 9
Module Block Diagrams 11
Input Module 17
Module Description, Operation and Specification 18
Output Module 23
Module Description, Operation and Specification 24
Master Module 27
Module Description, Operation and Specification 28
Appendices 35
Specification Notes 36
Performance Specifications 37
Configurations 38
Dimensions 39
Warranty 40
Glossary 41

Introduction
Introduction 1

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The SM12 is a 12 bus dedicated monitor console to complement the Vienna and
Europa FOH desks.
The key features of the SM12 are:
•12 mono sends
•stereo send
•PRE/POST fade switching on each pair of sends and the stereo send
•4 programmable mute groups
•4 band sweep EQ
•100mm linear faders on all inputs and outputs
•sophisticated solo system with autocancel, central global clear and
switchable input priority.
•metering for all inputs and outputs
•external inputs for all group and stereo mix buses, with level control and
listen facility
•balanced inserts on all outputs with bypass switching, and pre-insert solo
facility
•balanced inserts on all inputs
Frame Sizes
The SM12 is available in three frames sizes, 32, 40 and 48 channels. The consoles
are configured, from left to right:
•inputs 1 - 24
•master
•groups 1 - 12 (6 modules)
•inputs 25 - 32 (32 channel)
•inputs 25 - 40 (40 channel)
•inputs 25 - 48 (48 channel)
Power Supplies
All frame sizes use the PSM300 PSU. Connection to the console is via a 10-way
SRC connector below inputs 21-24. The console rear panel also carries a ground
binding post.
Lamps
Two 4-pin XLR connectors for lamps are fitted to all frame sizes - one at either end
of the console on the end trim. These are suitable for Littlite or similar 12V lamps
taking up to 330mA each.
2Introduction

Metering
Each input module has its own 8-segment bargraph meter and peak level indicator
adjacent to the fader. The groups are metered by 16-segment bargraphs which are
next to the faders on the output modules.
The two 16-segment bargraphs on the Master module meter either the PFL/AFL
signals or the Stereo Mix signal depending on the wedge default internal setting.
Introduction 3

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General Precautions
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 alcoholto cleanthe trim andscribble strips.Other solvents may cause
damage to paint or plastic parts.
Avoid using the console close to strong sources of electromagnetic radiation (e.g.
videomonitors,highpowerelectriccabling):thismaycausedegradationoftheaudio
quality due to induced voltages in connecting leads and chassis. For the same
reason, always site the power supply away from the unit.
Caution!
In all cases, refer servicing to qualified personnel.
Handling and Transport
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 regularly moved we
recommend that it is installed in a foamlined flightcase. At all times avoid applying
excessive force to any knobs, switches or connectors.
Power Supplies & cables
The power supply unit incorporates automatic mains input voltage sensing and
therefore no adjustment is needed to match local mains supplies.
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.
Warning!
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 SM12 uses the
PSM300 power supply.
4Introduction

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 commonmode DC, AC or RF voltages, as these will reduce 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
+28dBu on the lower sensitivity range, and +18dBu on the higher 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 are balanced at a nominal level of +4dBu, with a maximum
output level of +26dBu.
All external inputs and mixand group insert returns have anominal level of +4dBu,
and a maximum input level of +26dBu except the AFL/PFL external inputs which
are unbalanced at a nominal -2dBu, with a maximum input level of +20dBu.
Insert returns are balanced at a nominal level of +4dBu, and a maximum input level
of +26dBu.
Introduction 5

6Introduction

Installation
Installation 7

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TheSM12isdesignedforreliabilityandhighperformance,andisbuilttothehighest
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
AFor optimum performance it is essential for the earthing system to be clean and
noise free, 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 tothe systemstar pointto providea safetyearthreferencefor eachpiece
of equipment.
BInstall separate mains outlets for the audio equipment, and feed these
independently from any other equipment.
CAvoid locating mains distribution boxes near audio equipment, especially tape
recorders, which are very sensitive to electromagnetic fields.
DWhere possible ensure that all audio cable screens and signal earths are
connected to ground only at their source.
Power Supply
Always ensure that you use the correct PSU for your mixer. The SM12 uses the
PSM300 power supply.
Thepower supply incorporatesautomatic mains input voltagesensing and therefore
does not require adjustment for different local mains supplies.
Warning!
Before switching on your SM12 console, check 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.
8 Installation

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Wiring conventions
The SM12 uses two different types of audio connector: 3-pin XLR and 1⁄4" 3-pole
jacks. These are used in several configurations, as shown below.
MICROPHONE INPUTS
TALKBACK MIC
TALKBACK INPUT
STEREO MIX L, R & WEDGE OUTPUTS
GROUP, TB & OSCILLATOR OUTPUTS
1
/ 4 " ‘A’ Gauge Stereo Jack Plug used as balanced input:
Hi-Z inputs, insert returns, external inputs
1/4" ‘A’ Gauge Stereo Jack Plug used as ground compensated output:
AFL/PFL outputs
1/4" ‘A’ Gauge Stereo Jack Plug used as stereo output: Headphones
1/4" ‘A’ Gauge Stereo Jack Plug used as balanced output:
Insert sends, oscillator
Installation 9

10 Installation

Module Block Diagrams
Module Block Diagrams 11

Input Module
12 Module Block Diagrams

Group Output Module
Module Block Diagrams 13

Master Module
14 Module Block Diagrams

Stereo Mix
Module Block Diagrams 15

16 Module Block Diagrams

Input Module
Input Module 17