ALLEN&HEATH GR1 24 Input 3 output Zone Mixer USER GUIDE (Installation) PUBLICATION: AP2057
GR1 LIMITED ONE YEAR WARRANTY This product has been manufactured in the UK by ALLEN & HEATH and is warranted to be free from defects in materials or workmanship for a period of one year from the date of purchase by the original owner. To ensure the high level of performance and reliability for which this equipment has been designed and manufactured please read this User Guide before use.
GR1 INTRODUCTION The GR1 continues ALLEN & HEATH’s commitment to provide high quality audio equipment engineered to meet the exacting requirements of today’s audio business. It brings you the latest in high performance technology and offers the reassurance of over two decades of manufacture and customer support. This user guide presents a quick reference to the function, application and installation of the GR1.
GR1 INTERCONNECTIONS Where possible use balanced connections for the inputs and outputs to minimise noise pick-up. Avoid running audio cables near to mains or lighting cables or thyristor dimmer units, power supplies etc. These may cause audible hum and buzz. The use of low impedance sources significantly reduces interference pick-up. Check the cables for correct wiring to avoid problems with phase reversal and unreliable connection.
GR1 SPECIFICATION 0 dBu = 0.775 Volts RMS 0 dBV = 1 Volt RMS Line level options: +4dBu (high level), 0dBu, -10dBV (300mV low level) INTERNAL OPERATING LEVEL: -2 dBu FREQUENCY RESPONSE: 20Hz to 30kHz +0/-1dB INTERNAL HEADROOM: ........... +23 dB MAX OUTPUTS: .......................... balanced +26 dBu 600 ohms max load DISTORTION: THD 0.04% Line in to mix out at 1kHz unbalanced +21 dBu 2kohms max load METERS: .....................................
GR1 INSTALLATION The GR1 fits into a 1U space in a standard 19" rack system. Alternatively the unit may be mounted into a cabinet or plinth, or simply used free standing. Dimensions shown are case size in millimeters. Allow extra space as necessary for the front controls (add 26mm) and for the rear connectors. Mount the console using 2x M6 bolts each side for maximum strength. These should be provided by the supplier of the rack kit. The rack should allow a minimum side to side opening of 445mm.
GR1 CONTROL FUNCTION input section LEV & PAN The top control adjusts the signal level to the L, R, & M mix. The lower control adjusts the position in the stereo image. In the centre click position, the L & R have equal signal levels. SOURCE The 3 way lever switch selects either MIC, AUX(OFF) or LINE inputs. PEAK The peak indicator illuminates when the channel signal approaches overload. MONO Selecting mono combines the AUX or LINE left & right input signals.
GR1 CONFIGURATION Remove the 6 crosshead screws securing the top cover to the chassis. Lift off the cover to gain access to the options. Apply caution if powering the unit with the cover removed. The GR1 offers unique flexibility in its ability to be configured to satisfy the exact requirements of each installation.
GR1 EARTHING THE AUDIO SYSTEM The chassis is connected to mains earth via the power cord. FOR SAFETY REASONS NEVER REMOVE THE EARTH WIRE FROM THE MAINS PLUG. Audio 0V is connected to mains earth by the internal ground lift link option. Selecting ground lift disconnects 0V from the chassis (mains) earth.
GR1 LINE INPUTS MONO AND STEREO LINE INPUTS 2 Mono and 3 stereo electronically balanced line inputs are available on 1/4" jack sockets. The stereo inputs provide individual sockets for left and right inputs. OPTION LINKS - LINE INPUT LEVEL Unbalanced sources may be plugged into these inputs. The inputs may be individually internally set for one of three standard operating levels by positioning the jumper links as shown. Note that two line inputs are set on one bank of links. +4dBu (1.2Vrms) 0dBu (0.
GR1 ROUTING THE CHANNELS TO THE OUTPUTS Each of the 6 channels may be routed as required to a combination of the 3 outputs L, R and M to feed up to 3 mono zones or one stereo and one mono zone. The L and R post level outputs may also be routed to the M output for situations where a L+R sum is required. Note that the channel inputs may be summed with L+R to provide an independent mix based on the L and R outputs.
GR1 PRIORITY DUCKING SYSTEM The GR1 offers a flexible ducking system that allows one or a combination of the 3 mono channels to duck (override) the level of the other channels by reducing their level by a pre-determined amount. For example this may be used for voiceover anouncements where the background music is dimmed by the microphone signal level. The channel or channels that cause the ducking are selected by pressing the front panel PRIORITY switches.
GR1 REMOTE CONTROL OF THE LEVELS Each of the 6 channels and the main L,R and M outputs are fed through high performance VCA (voltage controlled amplifier) circuits. These are controlled individually either by the front panel level controls or by external DC voltages connected to the REMOTE DC connector according to the setting of the internal jumper links as shown below.
GR1 ALARM OVERRIDE To allow automatic control of the system by an alarm recording or emergency announcement the GR1 includes a comprehensive alarm override feature. When activated the front panel ALARM ACTIVE LED lights and the 3 main outputs are automatically switched to the selected alarm audio source. This is selected by internal jumper links to be the ALARM AUDIO IN on the SYS-LINK IN connector or the local MIC 6 input.
GR1 EXPANDING THE INPUTS WITH SYS-LINK The number of input channels feeding the outputs may be expanded by connecting GR1 units together using the SYS-LINK system. A single cable connects the L,R and M outputs of one unit to the buss inputs of the next. Use screened multiway cable connected as shown below to standard 15way D-type male connectors. Do not interconnect the DIR OUTs to the AUX INs when linking L,R and M outputs.
GR1 EXPANDING THE OUTPUTS WITH SYS-LINK The number of outputs may be expanded by connecting GR1 units together using the SYS-LINK system. This may be used to provide more zone feeds from the 6 input channels. A single cable connects the 6 channel DIR outputs of one unit to the AUX inputs of the next. Use screened multiway cable connected as shown below to standard 15way D-type male connectors. Do not interconnect the L,R and M outputs to the L,R and M buss inputs when linking the channels.
GR1 USER GUIDE 17
