FilterEach mono input channel is equipped with a 100Hz high-pass filter, an invaluable tool for cleaning up the mix. The majority of live sound sources have very little content below 100Hz, and modern microphones have wide frequency response and can pick up bleed from nearby low frequency sources such as bass and kick drums. The filter can be used: on vocal channels to reduce mic handling noise and close proximity ‘popping’; on drum overhead mics to reduce kick and bass pick up; on higher frequency instruments such as flute and acoustic guitar; and on stage mics to reduce foot noise. Recording OutputsThere is a digital SPDIF 2-track output available from a RCA phono socket for recording direct to digital media, such as PC soundcards, DAT and digital audio processors. The recording send can be switched pre-fade if desired. An analogue recording output is also available. 4 Band Channel EQThe 4 band input EQ is every bit a pro tool. The low [60Hz] and high [12kHz] bands have shelving response, while the high-midrange band is sweepable from 350Hz to 6 kHz. Low-midrange EQ has a bell response at 250Hz – a frequency chosen to provide reduction of ‘muddy’ sounds and enhance ‘warmth’. Lamp SocketA 4 pin lamp connector is provided on the rear of the control surface.Specifically targeted at the needs of live sound reinforcement, these stereo consoles have from eight to twenty-four mono microphone/line inputs, with not only stereo main outputs, but also a mono output which may used full-range or as a sub-bass output. All have two dual-stereo input channels, digital S/PDIF outputs to recording devices and integrated digital effects processors. Two models are offered with stereo 500W power amplifiers built-in. Comprehensive signal routing and monitoring arrangements help integrate the mixers into a wide range of live-sound environments. The mixers are built into wedge-shaped chassis, intended for use on a flat surface. The side trims may be removed in the case of the versions; the mixer can then be rack-mounted. At the front of the chassis, the arm-rest forms a convenient carrying handle. Above this is a ‘scribble-strip’ for marking-up the uses of the various inputs and outputs. The models differ in the number of mono inputs and whether or not they have power amplifiers. The functionality of the input channels and the the output facilities is the same for all models except those with power amps. See below. Mono Channels - Microphone/Line These have a balanced XLR input for microphones, with switched 48V phantom power. The line input is balanced, with a 6.35mm jack socket which defeats the microphone input when a plug is inserted. A high-pass (100Hz) filter switch is followed by a mono insert jack and four-band equaliser, with swept high-mid frequency. This is followed by a mute switch, with LED, a ‘Peak’ indicator, the PFL button, and the 100mm fader with pan control. Foldback send controls are fed pre-fader; the two auxiliary sends are post-fader. Stereo Channels - Dual Input The upper stereo input is unbalanced, and uses a pair of RCA(phono) connectors. The second is unbalanced, connected with 6.35mm jack sockets. Each have a gain control and are then summed together. Alternatively the first input may be switched away to feed directly to the main left and right mixes instead, effectively giving extra inputs. After the sum of the two stereo inputs there is a two-band equaliser followed by a mute switch, with LED, a ‘Peak’ indicator, the PFL button, and the 100mm fader with balance control. Foldback send controls are fed pre-fader, the two auxiliary sends are post-fader, both are mono sums of the two channels, as is the PFL signal. ‘FX’ Channel This has a single stereo ‘External FX’ input using 6.35mm jack sockets and a gain control. This is summed with the output of the internal effects processor. There is no equaliser. The summing amplifier is followed by a ‘Peak’ indicator, the PFL button, sending a mono sum of the two channels to the mono PFL mix, the 100mm fader then the mute switch, with LED and an associated footswitch input. Foldback send controls are fed post-fader as a mono sum of the two channels. Effects Processor This offers a choice of 16 digital FX providing reverbs, delays, chorus and others. Main Output This has two channels, Left and Right. The two mixes have insert jack sockets and then feed the main faders. The post-fade outputs are summed with a feed from the two-track inputs, which has a a gain control and ‘2 TRK to LR” switch. This could perhaps be used to play background music prior to the performance, without tying up a full input channel. Following this mix there is a mute switch with LED, then the post-fade signal feeds off to other output sections as well as the two main, unbalanced, output jacks. Two-track Output Three RCA (phono) connectors provide unbalanced Left, Right and digital stereo S/PDIF outputs to feed recording devices. They are fed from the main left and right output, pre or post controls and switching. Mono Output This takes the two post-fade main outputs, derives a mono mix, and feeds the mono output jack unbalanced, through a level control. This can be used for mono PA systems, centre vocal-clusters or, with the low-pass 100Hz ‘Sub’ filter selected, can feed a mono sub-bass system. Foldback Outputs After the mix amplifiers, each has a fader followed by an ‘AFL’ (after fade listen) button feeding the PFL mix, a mute button with LED and the unbalanced 6.35mm jack output socket. Feeds to the PA output are taken after the mute switch. Auxiliary and FX Outputs After the mix amplifiers, each feed directly to the unbalanced 6.35mm jack output socket. The FX output is also fed to the internal effects processor. PA Output This takes feeds from Main left, right and mono as well as Foldback one and two outputs, after the fader and muting in all cases. Two buttons offer a choice of sources to feed the output; Left and Right or Foldback 1 and L+R Mono or Foldback 1 and Foldback 2. After the selection, two, four-band, semi-parametric equalisers are provided to adjust the output to suit the acoustics of the room and the sound system. Two unbalanced jack sockets provide ‘Slave’ outputs at this point. The two unbalanced signals each then feed a level control to adjust the output to suit the sensitivity of the sound system, with level and peak indication on each channel. The two channels are then balanced to help avoid problems with connection to a sound system at a distance and made available on the rear of the console on XLR connectors. Monitoring A stereo headphone output is provided using a 3-pole 6.35mm jack socket with associated volume control. This is fed from a choice of the two-track inputs or the post-fade main output. When a PFL or AFL button is pressed the signal is replaced with the mono PFL mix. Two LED bar-graph meters show the level of the resulting signal. General The rear of the console has an IEC AC mains power inlet with on/off switch and a 5-pin male XLR for an external DC input, to back up the internal supply. A four-pin power female XLR provides power for a gooseneck lamp. Performance: As is usually the case with Allen Heath designs, technical performance is appropriate, and often in excess of, that appropriate for the target application. Response, noise and distortion figures are good. Microphone channel EIN: 128dB, 150 ohm source. Residual output noise: Better than -89dBu, main outputs. For further specifications please visit www.allen-heath.com. Power source: 100-240V AC. Dimensions: 145 x 539 (h x d)mm. Width depends on model. Power Amplifiers Models with the -CP suffix are fitted with fan-cooled, stereo power amplifiers, to drive loudspeaker systems directly. The two amplifiers each offer 500W into both four or eight ohms loads. These models differ from the non-CP types as follows. The balanced PA outputs on the rear of the console and their level controls are replaced with two break jacks feeding amplifier volume controls and hence the power amplifiers. These have LED indicators for peak-limiting and signal levels as well as LED to indicate activity of the protection circuitry and excessive temperature. The amplifier outputs are on the rear panel, implemented as a pair of Neutrik Speakon locking loudspeaker connectors. Note 1: With side cheeks fitted. 145 x 437 x 484 (h x d x w )mm with cheeks removed for rack mounting.PA28 Shipping weight: Approx: 28 KG = 60 lbs. 

NOTE!There are a few light scratch marks on the case.

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