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Allen & Heath GL2

Studio/Live Rackmount Mixer By Paul White
Published May 1994

Paul White digs out his patch leads and powers up Allen and Heath's new general purpose, 4‑bus console.

Though the mixer market is undoubtedly crowded, there's always room for a new idea, and Allen & Heath have incorporated one or two novel concepts into the GL2 which distinguish it from the competition. Apparently, the original concept was to build a rack‑mount mixer that could handle Front Of House (FOH) mixing in live music or theatrical situations, but that was also capable of being used for recording and other general purpose mixing tasks. In itself, that's nothing new, but the GL2 includes a less usual mode which allows all four Groups, plus the two stereo outputs, to be used to feed a 6‑way stage monitoring system — impressive on a console of this size.

As with many rack‑mount consoles, the connectors are located on the rear panel, which means that table‑top operation is impossible unless the console is supported at an angle, leaving space for the plugs and leads beneath. There are 12 input channels (10 mono and two stereo), feeding four Group and two Master faders. The console is mains‑powered and equipped with stereo PPM LED metering, augmented by individual Peak LEDs on the channel strips. Further metering is provided on the Group and Left/Right outputs in the form of 3‑section LED meters showing signal present, 0dB and peak. Four Aux Returns bring the input total to 18, if you count a stereo channel as two inputs — which is how Allen and Heath come to describe the console as an 18:4:2:1 FOmixer, a 14:6 monitor mixer or a 14:4:4 recording mixer for 4‑track use.

Control Layout

The channel strips are pretty conventional, but the EQ and Aux Send sections deserve comment. The 10 mono channels have both mic and line inputs with individually switchable phantom power, and these have the benefit of 4‑band EQ with two sweep mids. The two stereo channels are line only and offer four fixed bands of equalisation. The sweep EQ sections provide a usefully wide range of control, with up to 14dB of cut or boost per section; the High and Low controls are fixed shelving filters operating at 12kHz and 80Hz respectively, with the two mids covering the ranges 35Hz‑1kHz and 550Hz‑15kHz. The EQ in the stereo channels operates at 12kHz, 3.5kHz, 250Hz and 70Hz, which seems a sensible compromise. EQ bypass switches are fitted to all channels.

All channels are fitted with six Aux Sends split into one group of four and another of two, each group having a Pre/Post switch. This is a generous number of sends for such a small mixer, and further customisation of the Pre/Post status is available to those prepared to delve inside the mixer and move links — a useful option when planning fixed installations, where it may be desirable to have some channels configured in different ways to others. Insert points are also provided on the mono channels but are, understandably, omitted on the stereo channels.

Though the mixer market is undoubtedly crowded, there's always room for a new idea, and Allen & Heath have incorporated one or two novel concepts into the GL2 which distinguish it from the competition.

The routing system allows any channel to be routed to the Left/Right stereo mix buss or to Group pairs 1,2 or 3,5, and the switching system allows any combination of these destinations to be selected simultaneously. While mixing, the Groups may be routed to the stereo mix for conventional subgrouping. Both the input channels and the Groups are fitted with Mute switches, and PFL (Pre Fade Listen) Monitoring is available on all channels. The Groups each have an AFL (After Fade Listen) button, as do the Left/Right faders and the six Aux Send Masters. All the faders are 100mm‑travel carbon types.


The key to the GL2's versatility is in the Group section of the console. In a conventional PA/FOapplication, the groups work normally, allowing channels to be subgrouped for easier control or, alternatively, to be used to route elements of the mix to a separate amplifier/speaker system. But the GL2's recessed Grp/Aux Rev buttons turn the mixer into a monitor desk. In this mode, the six Aux Send levels are controlled from the six Group plus Left/Right faders, and emerge from the Group and Left/Right balanced XLRs on the rear panel. The Group outputs are now routed to the original Aux out sockets, and are controlled by the Aux Send Master level controls.

The console also features a mono output, which can be sourced either from the sum of the Left and Right outputs or, if the GL2 is being used as a monitor desk, from the Group outputs. This latter mode would normally be used to drive an engineer's wedge monitor system, fed by pressing the desired Group (here functioning as Aux) AFL switch. Pressing any PFL still allows the engineer to check individual channel signals.


The master section of the console has 2‑track monitoring, while the four Aux returns are designed to double as Off‑Tape monitors, offering basic level and pan control only. The GRP/Ret switches may be used to switch between monitoring the Off‑Tape signal and the To‑Tape signal fed via the Groups. During recording, the first four channel Aux sends would generally be used post‑fade to provide effects sends, while the remaining two would be used pre‑fade to provide a musicians' cue mix. During mixdown, these two can be flipped to Post‑Fade to provide a further two effects sends.

The four tracks of the tape machine will normally be patched permanently to the four Group outputs, but when it comes to mixing, the multitrack outputs will have to be repatched from the Aux returns to four of the desk input channels. To avoid this repatching, Y‑leads can be used, so that the multitrack outputs feed both sets of inputs at all times. This does mean using input channels as effects returns at mixdown, but as there are two stereo channels available, this shouldn't be a problem. Alternatively, a simple patchbay or switch box provides the best of both worlds.


This is a very workmanlike mixer, with a couple of simple but well thought‑out twists added to greatly increase its flexibility in a variety of applications. For those who only want a mixer for use in a home music studio, some of these extras may be irrelevant, but for others, who are obliged to use the same mixer for recording and gigging, the extra flexibility could be a key issue.

This is a very workmanlike mixer, with a couple of simple but well thought‑out twists added to greatly increase its flexibility in a variety of applications.

When it comes to quality, the GL2's circuitry is derived from that used in other Allen & Heath consoles, which puts it on a par with most mid‑market consoles in terms of noise and crosstalk. However, the EQ is very flexible and smooth‑sounding, while the overall sound quality is as near neutral as you could hope for on a desk of this type. Indeed, I feel the EQ is more useful than, say, that on the Allen & Heath GS3, because of the extended range at the lower‑mid end of the spectrum.

Ergonomically, the GL2 is very sensibly set out, with clearly marked controls and just about enough room to get your fingers between the rows of controls without difficulty. Recessing the more radical switches is definitely a good move, though having the individual phantom power switches on the rear panel isn't quite so convenient if the console is mounted in a rack full of equipment.

As I said at the outset, the mixer market is already pretty crowded, so the GL2 isn't going to have an easy ride. However, it is a well‑built, nice‑sounding mixer, with a great EQ section, plenty of Aux sends, and enough facilities to make it useful in most mixing environments, including 4‑track recording and live sound.



  • Line In Balanced jack, ‑40 to +10dBu
  • Mic In Balanced XLR, Low Z, ‑60 to ‑10dBu
  • Inserts TRS Jack (Tip Send, Ring Receive)
  • Stereo In Unbalanced jacks and phonos
  • Returns Unbalanced jack


  • Left/Right,
  • Mono and Groups Balanced XLR (+4dBu nominal)
  • Aux Sends Unbalanced Jacks
  • Group, L/R Inserts TRS Jack (Tip Send, Ring Receive)
  • 2‑Tr Send/Return Phonos
  • Headphones Stereo Jack (8‑400 ohms)


  • Frequency Response 20Hz to 20kHz +0/‑1dB
  • Distortion THD 0.01% line in to mix out at 1kHz
  • Noise (22Hz‑22kHz)
  • Mic EIN ‑127.5dB into 150 ohms;
  • Line Preamp at 0dB, ‑88dBu;
  • Mix Noise ‑85dB ref 0VU
  • Crosstalk Output mute better than 100dB, channel mute better than 90dB, fader shutoff better than 90dB 91kHz)
  • Phantom Power 48V CD at 50mA (individually switched)
  • Size 484 x 488 x 90mm
  • Weight 10.5 kg


  • Flexible, musically sympathetic EQ.
  • Sensible number of Aux sends.
  • Versatile routing system.


  • Rear panel Phantom power switches difficult to operate if the mixer is rack‑mounted.
  • No front‑panel Phantom Power status LEDs to show which inputs are powered.


An exceptionally well‑designed desk, which will appeal most to those who need to use the same mixer for a number of different purposes.