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Product Review by Ross Tester Redback 8-channel Pro Mixer A ltronic Distributors recently submitted one of their “Redback” brand professional quality mixers for evaluation and review. First impressions are important – and the Redback mixer certainly makes a good first impression. It is a very smart looking unit, mounted in a black 1-unit rack-mounting case, around 150mm deep. On the front panel are the eight individual channel level controls, a master level control, a five-LED “VU” meter, power and signal LEDs, headphone socket and power switch. We were rather pleased to see traditional (rotary) pots used for the level controls. Common practice in many (most?) mixers these days is to use slider pots. That’s fine if the mixer is always used in a controlled (ie, inside, air-conditioned) environment. But if you don’t - you take the mixer on the road, or to “events” - the chances are that slider pots will become noisy much quicker than rotary pots. A small point, perhaps – but one that experience has taught us is important! Above each channel level control is a pair of screwdriver-adjustable treble and bass controls giving +/-10dB and 10kHz and 100Hz boost and gain. Clever move, making them relatively tamper resistant: in the majority of cases, you’d want the tone controls to be “set and forget”, without the possibility of “knob twiddlers” changing your settings. On the rear panel are all the inputs – each channel has a balanced XLR mic socket (200-600Ω with 1.25mV sensitivity), along with a stereo pair of (unbalanced) RCA sockets (100kΩ). Selection of the input is achieved by a four-way DIP switch immediately above each XLR socket. The DIP switches on channels 1-6 also allow these channels to be selected as priority channels (overriding other inputs); select the “aux” input sensitivity (100mV or 1V); and also allow phantom power (12V nom) to be turned on/off (for those microphones which need it). Channels 7 and 8 are slightly different: they are dedicated line inputs and here the DIP switches can only select the input sensitivity. Output is by way of a 3-pin male XLR socket (600Ω, balanced 0dBm) and/or dual RCA sockets. Also on the back panel are the 3-pin IEC mains input, a 3.5mm DC output socket and a preset VOX mute level control. Inside If the outside of the case impresses, the inside does perhaps more so. There are three double-sided PC boards. One handles the inputs and outputs (fixed to the back panel by the XLR and RCA sockets); one handles the level selection, LEDs and headphone socket (fixed to the front panel) while the largest board has the power supply and the main mixing circuitry itself. Also on the main board are two sets of headers, handling a chime/alert/evacuation tone generator and a compressor/ compander (both optional). The tone generator is used where the mixer is used in a building and various tones are required. These take priority over other signals. The compressor/compander is used when a CD or DVD is used as a background music source to maintain a relatively consistent output level. This eliminates the constant adjustment of volume levels which would otherwise be required, given the wide dynamic range of such sources. In use We gave the Redback A4425 a run for its money replacing a “known quantity” mixer in a large public address system. A variety of input devices was used, including standard microphones, radio mics, a CD and tape player. It performed flawlessly; indeed, was a pleasure to drive. If you are looking for a high quality, high performing mixer you’d find it hard to beat the Redback A4425. The fact that it is made in Australia and comes with a two-year guarantee is a bonus. Recommended retail price is $649.00 (or $595 for two or more) and it is available from all Altronics outlets, most resellers or from AltronSC ics mail order. The rear panel is pretty busy with eight XLR/RCA inputs, outputs and DIP switch input selectors. www.siliconchip.com.au April 2004  81