Oberheim GM 1000 and GM 400 multi-effects processor.

The GM-1000 and GM-400 are the fruit of a joint effort between Gibson Musical Instruments' Oberheim division and Viscount, one of the oldest and most respected electronic instrument manufacturers in Italy.

Sure, there are lots of rack mount guitar processors out there, but you truly would need a whole rack full of gear to do what the GM-1000 does.

The GM-1000 starts with a warm and musical-sounding preamp, complete with a compressor/limiter and three tube-like flavors of distortion (with 33 different EQ curves)--but you'd expect that from a quality company like Oberheim. You'd also expect five varieties of mono and stereo graphic or parametric EQ, plus your standard assortment of studio-quality reverbs, chorus, flanger, phaser, tremolo and vibrato. But the advantages of the GM-1000 become more apparent when you get into "special effects" such as three-voice pitch shift, arpeggiator, tap delay, comb filter, smart noise reduction, rotary speaker simulator, guitar AND bass amp simulation, plus effects which allow you to change parameters in real time (via expression pedal), such as wah-wah.

Still not impressed? The GM-1000 has stereo " and XLR inputs and outputs, a chromatic tuner, two metronomes, full MIDI implementation and if that weren't enough, a 31-band spectrum analyzer, which instantly "pink lights" any club or studio you play and automatically adjusts its parameters, giving you the best possible tone at all times (when was the last time you. played a device that sounded great in a guitar store, only to find it sounds awful everywhere else?) Add a custom-designed foot controller and massive programming parameters, and you have a recording and performance tool that truly is as powerful as your own imagination--all in two rack spaces.

Want all the quality sounds, but don't like to fiddle with knobs? For the "plug in and play" set, Oberheim presents the GM-400. Lighter on the wallet, and requiring only one rack space, the GM-400 packs all the same effects as its older brother (including its high-performance 44.1 kHz sampling rate), sacrificing only a degree of programmability. But with 128 awesome presets, chances are, you won't miss it.

"You have, at your fingertips, just about every effect known to guitarists without all those boxes and cables underfoot and connections that can go wrong," said Bill Nelms, Oberheim product manager. "With this piece of equipment you eliminate the need to go out and buy something new every time.you want to experiment and create a new sound."

I took a few minutes (that turned into almost an hour) to plug a Gibson ES-135 into the GM-1000 and check it out for myself. I'm from the aforementioned "plug and play" set myself, so I was particularly interested in the presets. More importantly, I was interested in the tone. Who cares how many features something has if it doesn't sound good, right?

Using a 2x12" solid state combo amp, I plugged the output of the GM-1000 directly into the effects loop "return" of the amp. This enabled me to use the amp for volume without it coloring the sound in any way. In other words, the GM-1000 was functioning as an effects processor AND preamp.

I have used many preamps before, including models that include actual tubes in them. My opinion has pretty much been that the tone, especially the quality of the distortion, pales in comparison to that of a traditional guitar amp. I was especially skeptical about the Oberheim due to its solid state circuitry.

I am happy to say that Oberheim and Viscount have done their homework. Choosing a dry preset (one that lacks effects) I found that the distortion has a crisp and meaty low end, complex midrange and a nice "chirp" on the high end without sounding harsh. You could hear definition in each individual note of a chord while single sustained notes had bite without sounding thin. I'd like to compare it to a popular amplifier brand, but don't want to use the "M" word. Scrolling to presets featuring the dizzying array of effects instantly gives you tones typical of a professional "session" musician; very refined. Best of all, the onboard compression smoothed out the rough spots in my technique (who says good equipment can't make you play better!).

Like I said earlier, I'm not one for sitting around and tweaking knobs. But I have to admit, the huge display afforded by the two-rack-space size took a lot of hassle out of changing parameters. EQ curves are there for all to see, plus a generous supply of buttons allow you to call up each individual effect you wish to change settings on (the less scrolling through menus, the better).

Other features I liked were the separate and stereo XLR and " outputs, which enable you to send signal to both your personal power amp AND the mixing board during live performance. The chromatic tuner (with special settings for five and six-string basses) was the icing on the cake.

In a nutshell, this really is a unit you could spend a year with before truly discovering all its useful features. But it sure is impressive right out of the box.