Fine-tuning your sound is a simple affair thanks to all the buttons and dials at your disposal. There's one 1/4-inch jack for your instrument cable to the left of the analog control knobs, with 1/8-inch jacks to the far right for plugging in a set of headphones or wired sound source.

The Mustang GT amps also function like a big Bluetooth speaker. I was able to connect to the 200 and play some of the songs my band covers via Spotify, then play my guitar along with them to practice my solos and various parts. While I'd never recommend an $800 amp to just play music through, you might as well if you've already got one. The sound is relatively flat without any color, as it's acting more like a studio monitor when you're playing music through it. If you like your tunes with a bit more bass or treble, you'll have to use your music player's EQ settings, as the physical controls on the amplifier only affect the guitar sound, not that of any streaming audio.

The rear of both the 100 and 200 amps has a balanced set of left and right XLR line out jacks, a micro-USB port to connect to your computer for recording, and two sets of jacks for an effects loop (if you need to add even more guitar effects to the end your signal chain). The GT 200 comes with a four-button foot switch, also available separately for the GT 40 and 100 models. Being able to control the amp with a foot switch is all kinds of great, but it's limited. Quick Access mode only gives you the ability to switch among three presets from your amp, though you can assign any three of the 100 included presets you like (plus any of your own creations).

Presets mode, as you might guess, lets you scroll through all the presets -- but in groups of three only. In other words, you can have presets 1-3 enabled on three of the foot switches, but then you have to depress the right two pedal buttons to put the switch into scroll mode, then choose the next three presets, 4-7, or press two buttons again to cycle to 8-10. It's overly complicated and much faster to just twist the big knob on the amp or use the app to switch presets (if Bluetooth is working).

Effects mode essentially assigns the three foot switch buttons to one single preset. So if you have an overdrive, a delay and a wah-wah sound in your effects chain, you can turn them off and on with the three buttons. Again, this is fine if you have a simple effect chain but kind of useless if you have more than three effects assigned to a preset.

With all of this choice, how does the Fender Mustang GT sound? Honestly, the GT100 sounds a little brittle, especially at higher volumes. Both sound guys mentioned it when I used the amp onstage. The GT200, with its dual-speaker setup, has a little more well-rounded, fuller sound, but it's still a solid-state amp. That means those looking for a warmer, fuller sound could be somewhat disappointed.

The Fender Tone app

While the Mustang GT does all the above on its own, Fender also created a companion app so you can control it from a distance. Once connected via Bluetooth, you can choose and customize any of the presets via the app instead of the physical knobs on the cabinet. The problem here is getting your amp to stay connected, especially in a live-performance setting.

My iPhone locks its screen after a given time; that's how it saves my battery. Most of the time that it locked, however, there seemed to be a disconnect with the Mustang amp. I ended up fiddling with my phone for far too long onstage, to the point where I just gave up and used the knobs on the amp itself. If it had been placed in the back line of the stage, it would have been impossible for me to get to it.

Having an app to mess with is fantastic at home, though, since it allows you to both change the settings and order of effects visually. In addition, the app is where you grab presets from Fender's "community" section, which has groups of settings for various genres and artists ready for download. I grabbed a preset to sound like Slash on "Sweet Child O' Mine," an AC/DC set for "You Shook Me," a "Sultans of Swing" preset and a sound that mimics the lead on Pink Floyd's "Comfortably Numb."

Not all of my downloads were winners, of course; many of these are created by amateurs at home, and the quality varies. Still, I was able to download 10 presets in a matter of seconds, each one ready to go on the amp with a tap on my iPhone or rotation of the dial on the amp itself. You can create set lists of presets, too, which would have been helpful onstage, if only the Bluetooth was reliable.

There are 110 preloaded effects presets on the amp already, with room for 90 more downloaded or created sets. The Mustang GT offers 21 different amp models, including popular models like Fender's Champ, Twin Reverb or Deluxe. There are British amps in the list, too, with Hiwatt, Vox and Marshall models to add into your signal chain. There are 12 "stompbox" effects (which include distortion, compression and wah-wah sounds), 13 modulation effects (chorus, flanger, phasers and tremolos), nine delays and 12 reverb effects to choose from. It's an overwhelming amount of choice, to be honest. Most guitarists look for their own unique sound that ends up coming from their own choice of amplifier and pedal effects. It almost feels like overkill to have so many options, but that's the glory of digital.

While I'm no expert on the original sound of each modeled amp, I can say that the Super Champ model in the Mustang GT sounds very much like the actual Super Champ I use normally. All the 17 amp models have a unique sound profile to them, and I found myself gravitating to more-crunchy tones than I usually do, having access to them with the turn of a dial.

The built-in effects presets are a mixed bag, of course. The standouts include the auto wah-wah sound and a couple of fuzzbox effects, while the reverb settings tended to sound rather sterile. I had a ton of fun with the tremolo and tape delay effects, too, creating out-of-this-world, spacey guitar sounds in a matter of moments.

Having all of these sounds and effects available makes it much easier for me to play different songs. It's a matter of a pedal press to move from the treble-heavy distorted sound for AC/DC's "You Shook Me" directly to the chorus-laden tones of Prince's "Purple Rain," even if they're one after the other in our set list for the night. Both sound much more authentic than the tones I was ever able to create with my few discrete guitar pedals.

Wrap-up

Ultimately, the Mustang GT amps are a solid choice for guitarists looking for a little help in finding and creating a diversity of guitar tones. Control via a mobile app sounds great on paper, and in a controlled setting like a rehearsal room or recording studio, it makes a ton of sense. If I were purchasing a new Mustang GT for myself, I'd opt for the larger, better-sounding 200 version. It also comes with the foot pedal, limited as it is, for a bit more control while playing.

If you're looking for a real tube sound, though, no amount of digital modeling will get that elusive warm tone. It's not that the GT amps sound bad; it's more that they sound digital. That may be a good trade-off if you need a variety of sounds, like I do when playing a set list full of disparate tunes. If you don't already have an array of pedals at your disposal, the Mustang GT amps can certainly keep you rocking, whether you want to play disco, punk, metal or blues.