The GT-Pro is BOSS's most powerful rack processor ever and comes equipped with a dual COSM effects engine and plenty of connection options.
It's intended for both stage and studio use, either as the front end, driving powered cabinets, or for direct recording through analogue, digital or USB connections.
Versatility is the name of the game with the GT-Pro. Although many of the onboard sounds and features are also found in the GT-8, the GT-Pro takes connectivity to another level altogether. The main signal output is via a pair of jacks, but internal routing enables you to send another signal to a 'sub' output that's available on balanced XLRs, as well as jacks.
There's also a digital output. The creative versatility comes not just from the range of onboard sounds but in the form of connections for three separate effects loops for additional external pedals or processors. One loop comes before the GT-Pro's processing and is ideal for adding a favourite wah or overdrive pedal before the effects, while the other two together can be placed anywhere in the internal effects chain. With so much processing power on board, the GT-Pro also offers the opportunity to instantly tap into it with a wide range of switching possibilities. This includes no less than five jack sockets for various control and expression pedal options plus the possibility of using a MIDI pedalboard.
There are 400 patches in the GT-Pro: 200 of these are presets that cannot be overwritten, although they can be edited and the edit saved to one of the 200 user patches. A patch consists of a signal chain of up to 15 effects blocks that can be configured in any order. Obviously, in a unit of this nature, amp and speaker simulation is the foremost building block in creating any sound, and there are 46 amp variations, based on a core of 11 basic types.
With the dual COSM engine, any two amp variations can be used in a patch for two-channel (A and B) operation. These two channels can be used individually or combined in several ways. One very cool feature of the GT-Pro is a dynamic sensing mode, whereby the channels can be switched in response to guitar volume.
As well as the channel switching, there's also a solo switch so you can bring in a louder lead tone on any amp channel. Following on from the amp/speaker simulation, there are effects blocks for compression, overdrive/distortion, wah, EQ, delay, chorus and reverb, plus FX1 and FX2, both of which can have a single effect from a pool of several assigned to them. Each effect can include both preset and user 'quick settings', so that favourite sounds can be recalled without having to adjust all the parameters - of which there are plenty - should you want to get into some deeper editing.
It's difficult to see how the front panel of the GT-Pro could be laid out any better - the sections for all of the different functions are nicely delineated and everything is clearly labelled. The preamp/ speaker functions are the easiest to access. As these are likely to be the things that are most often tweaked, they've been given a row of rotary knobs for amp selection, gain, bass, middle, treble, presence and level. The rest of the blocks in the effects chain are accessed by a dedicated button and any parameter editing can be swiftly carried out using a pair of cursors and a large rotary 'value' knob.
With 200 preset patches available, Boss has had the opportunity to cover all sonic aspects of the guitar player's art, and it rarely disappoints. While a couple of banks contain the more esoteric effects patches, some of which are designed to impress and might leave you scratching your head and wondering how to use them in a valid musical context, the vast majority are practical, workmanlike sounds that can be used straight out of the box or quickly tweaked to get closer to the sound in your head. These are arranged in carefully organised banks so you get a whole bunch of, say, clean sounds to audition together.
While only a relatively small number of real-world amps have been modelled, the range of amp and speaker sounds possible from the available variations is staggering, and there's plenty of potential for getting away from the old favourites and creating some new hybrids. There are just about all the effects you'd need too, from all the standard Boss pedal sounds through to weirder stuff like Auto Riff, where you get a phrase from playing a single note. There's a wealth of options available for creating new effects sounds, particularly in changing the order of effects in the chain and perhaps adding some of your other pedals or processors to the mix.
While this can all be done in a very practical manner from the front panel of the unit, it's a much more intuitive and fluent process to use the software editor, with its visual representation of the signal chain as a row of Boss pedals that can be grabbed and moved with the mouse. In a studio situation, the GT-Pro really comes into its own with the various options of recording and monitoring the signal.
Once the software drivers have been installed, recording through the USB interface is as painless as using any soundcard. Live use would be a different matter straight out of the box because of the switching needed, but adding some footswitches gets the system up to speed. Also, there's the onstage ability to change channels and bring in a lead sound when needed. Adding an FC-200 MIDI foot controller gives plenty of freedom to control the effects. Overall, Boss seems to have covered all the options with the GT-Pro, making it extremely versatile, as well as a great-sounding unit. There's plenty of conventional stuff here, but it's the little extra functions that make it special - things like the dynamic sensing, which can not only be used to switch between amps, but can also be used to alter effect parameters.
The GT-Pro is no pocket-money toy. It's a big investment but, on balance, you get your money's worth. If it's just the basic sounds you're after, the GT-8 at some £300 less may be the better option. However, what the GT-Pro brings to the table is an awful lot more versatility.