You are here

Lexicon MPX G2

Guitar Effects Processor By John Walden
Published March 1999

Lexicon MPX G2

Is it a bird? Is it a plane? No, it's a new guitar‑oriented effects unit from Lexicon. But will it inspire our mild‑mannered reporter John Walden to turn his Clark Kent chords into guitar (super)heroics?

It used to be that recording the guitar could be a pain in the... well, ears actually. Many classic guitar sounds used to be achievable only by cranking up a very large amp to the topof its range, and though this is still the only way for some, there has never been a better time to record guitar without leaving everyone in the vicinity with permanent ear damage. The market for effects units incorporating amp simulation caters for those on a budget (the Zoom 503 reviewed in the October 1998 issue of SOS), those on a bigger budget (Line 6's POD, reviewed in February 1999) and those to whom 'budget' is simply not an option (the Digitech 2120 Artist, reviewed in December 1998). The latest temptation comes from Lexicon — for many studio owners the name synonymous with quality reverb. The MPX G2 Guitar Effects Processor and the optional MPX R1 floor controller carry a pretty hefty price tag: can Lexicon carve themselves a suitable top‑of‑the‑range niche in an increasingly competitive market place?


The optional MPX R1 foot controller offers 16 on/off switches and a rocker pedal for effects such as wah.The optional MPX R1 foot controller offers 16 on/off switches and a rocker pedal for effects such as wah.

The physical appearance of the MPX G2 owes a lot to that of Lexicon's MPX1 multi‑effects unit (reviewed by Paul White in January 1997) and, like its forbear, the G2 uses multiple DSP chips to generate its digital effects. One chip is dedicated to reverb so that no DSP power is stolen from the reverb algorithm, whatever other effects are used within a particular chain.

There is also some serious analogue circuitry lurking within the unit. This provides Lexicon's 'Dynamic Gain' distortion technology, used to create simulations of classic guitar stomp boxes and a highly editable preamp for DI recording. Unlike some other guitar processors currently on the market, the MPX G2 does not use tubes in generating the amplifier simulations.

An interesting design feature of the G2 is the range of three different configurations available. These are designed to allow the user to integrate the unit fully into their existing guitar/amplifier/effects rig, either in a live or recording context. Stand Alone mode provides direct connection to a mixing desk or headphones: Amp Input Only mode is for connection to a guitar amp that does not have an effects loop, and Amp Input & FX Loop mode can be used with a guitar amp that has either a mono or stereo effects loop. The G2 can therefore be your sole sound source or, if your amp is doing its stuff, a means of adding a combination of a simulated guitar foot pedal and some digital effects to your basic amp tone.

Panel Games

Figure 1: In Stand Alone mode (a), the MPX G2 is configured as a conventional guitar preamp and effects processor. In Amp & Effects Loop mode (b), the pre‑gain ('stomp box') effects and preamp are located between the guitar and the amplifier, while the post‑gain effects are patched into the amplifier's effects loop.Figure 1: In Stand Alone mode (a), the MPX G2 is configured as a conventional guitar preamp and effects processor. In Amp & Effects Loop mode (b), the pre‑gain ('stomp box') effects and preamp are located between the guitar and the amplifier, while the post‑gain effects are patched into the amplifier's effects loop.

The 1U rackmount G2's front‑panel layout starts (from right to left) with a power switch, followed by a set of eight push‑buttons which provide access to the key editing functions. To the left again is a large rotary knob that is used for program selection or parameter adjustment. This is followed by a matrix of nine buttons that can be used to turn on or off particular effects in the current program. The Tap button is used for setting delay tempos manually, and the A/B button allows a chosen parameter to glide between two settings (A and B).

The two‑part display comprises a 2 x 16‑character section for program name and parameter editing, and a large 3‑digit readout of the current program number. To the left of the display are controls for the low, mid and high frequencies of the Gain effect. These are not just straight tone pots, as in some programs they also influence the character of the overdrive or distortion generated. The final dual‑function knob controls the overall input (inner ring) and output (outer ring) levels. LEDs for input level and clip are positioned above this control. On the extreme left is a guitar input that accepts a standard quarter‑inch jack; inserting a jack here overrides the identical input on the rear panel. A‑D conversions are 24‑bit throughout.

The rear panel hosts a quarter‑inch guitar input and both XLR and quarter‑inch TRS balanced left and right outputs. The latter can also be used as unbalanced outputs. Also provided are quarter‑inch sockets for stereo headphones, an insert send (to send to an external preamp such as the input of your guitar amp), left and right insert returns (from your guitar amp's effects loop send; this also has a level control) and a pair of sockets for a footswitch and footpedal. The rear panel is rounded off by MIDI In, Thru and Out and a 3‑pin mains power supply. Unlike the MPX1, however, there is no digital I/O.

The manual does an excellent job of explaining how the unit should be connected for each of the three configurations and setting the levels between your guitar, the MPX G2 and your guitar amp. The LEDs make this process easy, and the analogue input can also be protected by a soft clipping circuit (called Soft Sat).

The MPX R1 floor controller is specifically designed to work with the G2. The 16 on/off footswitches and footpedal are all housed in a very sturdy casing that will certainly take the use and abuse dished out in the live environment. A 7‑pin DIN cable connects the R1 to the G2 and supplies the former with power. The floor controller operates in two basic modes: in Program mode, the footswitches provide various ways of selecting sounds. In FX mode, they mimic some of the controls on the G2's front panel, allowing individual effects to be switched in or out. Some sort of floor controller would be essential to get the best out of the G2 in a live setting, and it is certainly useful in the studio. It must be said that the G2 and R1 do work really well together.

Sound Control

The effects themselves are divided into seven 'blocks' — Gain, Effect 1, Effect 2, Chorus, Delay, EQ and Reverb — and within these groups a total of 76 individual effects are available (see the 'FX Highlights' box for examples). The unit stores a total of 300 programs, and the first 250 provide a range of presets. Edits to these are retained when the unit is switched off. Numbers 251‑300 can store new user programs, but at this price, offering only 50 'blanks' might be considered a little on the stingy side.

Many of the editing features of the G2 are identical in principle to the MPX1 (refer back to SOS's January 1997 review for further information). It has a similar program database system (programs can be sorted by type, for instance, as well as number) and the order of the effects within the chain can be arranged by the user. While each program offers a huge range of editable parameters, the editing process itself is straightforward, even though understanding how some of those parameters interact with each other does take some experimentation. The MIDI implementation is very thorough and, of course, user patches can easily be backed up via SysEx.

The comprehensive manual explains clearly all the editing functions and includes a particularly useful list of the various effects, their parameters and how much DSP power they use. It also contains a number of circuit diagrams that offer a very useful insight into how the signal path can be varied. While editing can be taken to considerable depths, I was finding my way around the basic editing functions within 10 minutes of getting the G2 out of its box, with only a quick flick through the manual's opening chapter.

Despite the similarities with the MPX1, it is worth highlighting some of the more unique features of the MPX G2 sound structures. As shown in Figure 1, the signal path is split into pre‑gain and post‑gain sections. As the user has full control over the order of the effects within the chain, any of the six digital effects blocks can be placed either pre or post the analogue gain section. The insert send to a guitar amp is always immediately after the analogue gain stage, so the user can decide what effects, if any, are passed through the guitar amplifier's own preamp. Routing Maps can also be set up that define the connections between effect blocks (mono or stereo) or whether the signal path is split into two parallel routes at a user defined point. All this means that the G2 has enormous flexibility in sound creation, especially when used with a guitar amp. A further feature worth a mention is the automatic routing performed by the G2 around any effects block (or the insert send and return circuitry) if it is not being used. This ensures that the cleanest possible signal gets from the input to the output.

The analogue Gain effects section is likely to be the first thing many guitarists will want to experiment with. Available effects include Tone, Crunch, Overdrive, Screamer, Distortion (all intended to simulate standard 'stomp' boxes) and the Preamp. Only one of these can be selected at one time, so if you want to use the preamp for recording without an amp, these virtual foot pedals are not available. While the G2 is a very long way from being just a guitar preamp, for many the quality of the amp simulations it produces will be a vital consideration. It is certainly highly editable, with tone controls both before and after the 'drive' stage. The most interesting parameter is 'Feel' which, according to the manual, tries to simulate the changes in distortion dynamics caused by different types of power‑amp rectifier circuits in solid‑state and valve‑based amps. On the Overdrive 'footpedal' effect, Feel apparently simulates the influence of different battery types (such as alkaline or carbon zinc)!

Another useful feature is the Soft Row button, which gives instant access to key parameters within a program. Along with the Gain controls, this provides an easy way to perform basic sound tweaking without having to delve too deeply. The parameters accessible via the Soft Row button are user‑definable in your own programs. Finally, it is worth mentioning that a number of settings can be configured globally for all patches, including the analogue speaker simulator. This can be very useful when moving between live, practice and recording contexts.

Time To Audition

So what does all this actually sound like? Two things struck me as soon as I plugged in and powered up. First, the quality of the digital effects is quite superb with, as you would expect from a Lexicon unit at this price, the cream of the crop being the reverb. Compared side‑by‑side with a workmanlike mid‑priced multi‑effects unit in my own rack, the difference was just startling. As you could use the Lexicon as a standard multi‑effects unit by taking the Gain effect out of the signal path, top quality reverb for your vocals or mixes might be a bonus if you purchased the G2 for its guitar processing.

The second thing that became apparent very quickly was how 'controlled' the sounds seem. While there is plenty of scope to go from ultra‑clean through blues and rock to ultra‑dirty, the sound never seems to lose its definition or fail to respond to the guitar and the playing style. A little experimentation yields guitar parts that sit really well within a mix, and you would actually have to be trying pretty hard not to get a thoroughly professional tone onto tape or hard disk. The sounds just exude class.

As with any guitar‑oriented unit, your opinion of the presets will depend upon your own tastes. I found I needed to add a little top end, using the Gain controls, to some of the programs, so if you demo the unit, be prepared to experiment a little. If you get the chance to try it out both with an amp and in Stand Alone mode, then do so, but the latter alone (programs 150‑248) give a pretty good idea of what is on offer. These are grouped into various types, including a series devoted to tones typical of some well‑known guitarists, amplifier types and 'studio spaces' (see the 'Virtual Reality' box). For example, if you are a fan of Jimmy Page, try Jimmy P (160) and just play any of the riffs from Led Zeppelin II. I'm sure Mr Page worked pretty hard in the studio to get his sound, but you can just dial up something pretty close from the preset list. The same is true of Angus (163), Sandman (165) and Tush (179). No prizes for guessing who these sounds are trying to imitate. The clean sounds are just as sweet, as Classic Detune (210) and the Police‑inspired De DaDaDa (224) illustrate — beautifully clean, crisp tones enhanced by some fabulous digital effects. If you want something a little warmer, the 'studio space' Jazz Club (202) provides a good basic starting point.

There are also a few off‑the‑wall programs that make good use of the processing power available. Rotary Cab (199) provides an excellent Leslie simulation, where the A/B button glides between fast and slow speeds of the speaker. EnvFilter LP (215) and TechnoChords (229) both provide a good demonstration of how playing dynamics can control a filter effect to achieve some distinctly synth‑like results. TremoWah (235) is nice and extreme, while Emaj/Min 3 (239) shows off the harmonic pitch shifting for instant Brian May harmony (and no, you are not restricted to playing in E!).

Two final points are worth making. First, unlike some guitar‑based multi‑effects units, the wah on this one is pretty close to the real thing, especially when used with the R1 floor controller. Second, the unit has a small number of programs designed especially for bass guitar, and these also sound excellent.


The bottom line is that the MPX G2 can produce some first‑class guitar tones and enhance them with some of the best digital effects currently available, including Lexicon's magical reverbs. So should you buy one? There is, unfortunately, no simple answer to this question. As a guitarist, if you are considering spending this sort of money on your rig, the odds are that you already own a quality guitar and an equally classy amplifier. There is absolutely no doubt that if you add the G2 and R1 to that combination you should be able to produce the right sound for any live or recording context (and if you can't, it's time to retire).

That said, with £1500 to spend you would have a lot of choice. The Digitech 2120 Artist is an obvious rival to the MPX G2 and comes in at just under £1000. On the basis of the preamp sections of these units alone, I think it would be difficult to choose between them — they are different, but both excellent. In terms of the quality of the digital effects and, in particular, the reverb, for me the Lexicon has the edge, but it comes at a higher price. If you already own a high‑quality preamp or effects unit, buying this Lexicon setup is going to result in some duplication. If you don't, you could probably also put together an excellent preamp/effects/floor controller combination from scratch using products from different manufacturers (including Lexicon's own MPX1, which some UK retailers are now selling at under £600) and have a considerable amount of change left from your grand and a half. What you would lose by doing the latter is the excellent integration between the G2 and R1 which, when it is critical that everything works first time, might be the difference between getting the job done or not getting asked back. The MPX G2 is a superb unit that demands serious attention but, unless £1500 is what you consider pocket money, the only sensible advice is to do some very detailed homework before you decide how to part with your cash.

FX Highlights

Each of the effects blocks contains a range of related individual effects. For example:

Gain effects:

Tone, Overdrive, Screamer, Distortion and Preamp.

Effect 1 and 2:

Harmonic Pitch Shift, Detune, Tremolo, Panners, Phasers, Compressors, Sweep Filter, Digital Distortion, Wah and Volume controls.


Classic Chorus, Flanger, Rotary Speakers and Panning effects.


Various single‑ and multiple‑band parametric controls in mono and stereo, high‑pass and low‑pass filters.

Delay effects:

Delay, Analog Delay, Echo, Ducking, 'JamMan' phrase sampler.


A full suite of Lexicon's classic true stereo reverberation and ambience effects.

Virtual Reality

Presets 180 to 199 provide a collection of 'standard' guitar amp tones for use in a DI situation. These include:‑

  • AmericanClean
  • AmericanOD
  • Roadhouse
  • Taxmania
  • British '60s, '70s and '80s
  • ModernHiGain
  • TransChorus1
  • Jazz Dark
  • Acoustic
  • Phone Filter
  • Rotary Cab

By contrast, programs 200 to 209 provide what Lexicon refer to as Studio Spaces. The intention here is to simulate a collection of virtual recording rooms that are commonly used in recording guitar tracks. These include:

  • Tracking Room: Uses Lexicon's famous Ambience effect to add space but without swamping the sound in reverb or decay.
  • Acoustic Room: For use with acoustic guitar.
  • Rhythm Rooms: Some simple but effective stereo treatments for rhythm guitar tracks.
  • Gated Verb: Guess!
  • MicPlacement: Simulates different mic positions in front of an amplifier.


  • That fabulous Lexicon reverb plus a range of other excellent digital effects.
  • For chords and lead work, the sounds seem to sit really well within a mix.
  • Excellent integration between the G2 and the R1 floor controller.


  • Absence of valves within the preamp might deter some guitarists.
  • Only 50 'blank' programs to store your own new sounds.
  • 'Stomp box' effects not available at the same time as the internal preamp.


The choice for the recording guitarist just got a little harder. If you are prepared to spend this sort of money on your guitar setup, give the MPX G2 a serious test drive as you consider your alternatives.