Fender Mustang GT 40 | Full Review (2019)

Fender Mustang GT40: A Versatile, Affordable Amp Packed with Features

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Jam-packed with modern features and technology, the best-selling Fender Mustang GT 40 is a tech-savvy guitarist's dream. At first glance, it's a great sounding amp with 40 watts of power and a pair of 6.5" speakers. But dive deeper than the exterior and you'll realize just how many great features are hiding underneath the surface. It's the first ever amp to come with built-in wi-fi! The Mustang is also outfitted with Bluetooth so you can stream audio without any cord clutter. You can even control the amp from your phone using the Fender Tone app! Connect it to your computer with a USB jack for high-quality recording. With 21 amp models, 46 effects, a built-in tuner, and more, the Fender Mustang GT 40 is an excellent value with more features than you can shake a stick at.

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Features of the Fender Mustang GT 40

  • 40 watts of power
  • 21 amp models
  • 46 built-in effects
  • USB jack for professional quality recording
  • Bluetooth for audio streaming and Fender Tone App connectivity
  • Aux input and headphone jack
  • Easy-to-read screen
  • 2-band EQ (3-band accessible via Fender Tone App)

Target Audience

The Fender Mustang GT 40 is an extremely versatile combo amplifier that will suit beginners and intermediate guitarists alike. It comes with everything a growing guitarist could ever need: multiple amp models for versatility, built-in effects for experimentation, a tuner, and easy preset management. It even comes with a USB input for professional recording for when you want to record some of your own music.

While you might think that the Fender Mustang's 40 watts of power would be enough for live gigs, think again. The GT 40's speakers are its Achilles heel. They're just too small to really bring the noise. A loud drummer will easily drown you out. Sadly, there's no speaker output, so you're stuck with the small built-in 6.5" speakers. If you love the features of the Fender Mustang, but need more volume, you should definitely upgrade to the GT100 (or even the GT200). The GT 100's 12-inch speaker and 100 watts of power will certainly be enough to get you all the volume you could ever need. If that's still not enough, then the GT200's 2x12" speaker configuration and 200 watts of power will fill the known universe with your music.

Looks, Build, and Weight

Fender Mustang GT40 side view

The Fender Mustang series of amps are quite simple and unassuming in style. Everything on this amplifier is black: the frame, the cloth grille, knobs, buttons - even the screws that hold it all together! The only element to betray the all-black styling is the silver Fender logo on the front of the amp. It's very eye-catching and lets everyone know you mean business!

The Fender Mustang GT 40 is a pretty trim amplifier. It weighs a mere 14 pounds and super easy to move around thanks to the carrying handle. Because its two speakers are only 6.5", the amp isn't a traditional 'square' shape. Rather, it looks more rectangular in silhouette. At only 10.5" (26.7cm) tall and 15.25" (38.7 cm) wide, the GT 40 doesn't take up a lot of space either.



You'll have a hard time trying to find a more technologically advanced amp than the Fender Mustang GT 40 modeling combo amp. Bluetooth connectivity allows you to connect to the Fender Tone App on your phone or tablet. Within the app, you can modify your amp's presets and control all its settings in real time. You can also download your favorite artist's presets, change your signal path settings, and more - all without leaving the app. Bluetooth also allows you to wirelessly stream music to your amp from Spotify, Amazon Music, Youtube, and more. Jam along to your favorite music without any wires getting in the way!

On the back of the amp is a USB jack. By connecting the amp to your computer, you can open up a Digital Audio Workstation (DAW) like Garageband or Reaper and record your amp directly. Because you're using USB, the recording will be extremely high-quality and professional.

Finally, the GT 40 comes with Wi-Fi capability for automatically keeping its firmware up-to-date, quickly downloading presets, and more. If you're not a fan of wires, then the GT40 is the amp for you.

Controls and Inputs

Top panel of the Fender Mustang GT40
The control panel found on the top of the Fender Mustang GT 40. Notice the bright settings screen.

As we mentioned before, you can control the Fender Mustang GT 40 using the Fender Tone App on your phone. If you prefer a more old-school approach, you also have the option of using the control panel found on the top of the amp. That's where you'll find the guitar input and the control knobs for gain, volume, and EQ. You'll also find a settings screen that you can use to fine-tune the settings for the different amp models. Finally, at the far right are the aux and headphone jacks - great for silent practicing.

The knobs on the GT 40 can be a bit confusing. There are two volume knobs on the top of the amp: one labeled 'Volume' and another labeled 'Master'. 'Volume' is a programmable knob that affects the volume of the amp within each preset. 'Master' behaves more like a traditional volume control in that it controls the overall volume of everything that's playing out of the amp.

Keep in mind that all of the knobs are programmable except the Master volume knob. This means that when you load a preset, the preset's settings may not reflect the settings physically dialed in on the amp. It may take some time to get used to this setup.

Control panel of the Fender Mustang GT40
Control Panel of the Fender Mustang GT 40 including the settings screen and rotary knob

When saving or loading presets, you'll be using this section of the amp's controls. The screen on the left displays all the relevant preset settings. It's also used by other sections of the amp, such as menu navigation and tuning. The rotary switch allows you to press and select different options. The buttons on either side of the switch are utility buttons that show the different editing options available to you.

Fender Mustang GT40 USB and footswitch input
The USB jack and footswitch input are on the back of the amp

On the back of the Fender Mustang GT 40, you'll find the Power switch and power cable input. There's also a USB output jack for easy connection to your computer, which we'll touch on a little later. There's also a footswitch input for connecting the Fender Mustang GT Footswitch. The multi-function footswitch gives you the flexibility to quickly change between presets and settings, activate the looper, or even toggle effects, hands-free! You can even pair the GT Footswitch with the EXP-1 Expression Pedal for even more subtle control over your effects.


The Mustang GT 40 comes with a whopping 46 built-in effects, including chorus, distortion, reverb, and more. You get a lot of control over editing not only the effects parameters (e.g. rate/speed, level, etc.) but also their location in the signal chain. This gives you an extreme amount of freedom to create your sound without having to shell out for a bunch of effects pedals. You can add new effects, bypass them, move them, replace them, or even delete them from presets altogether - all from within the Fender Tone App!


Fender Mustang GT Footswitch
The Fender Mustang GT Footswitch lets you control the looper, effects, and other amp features without lifting a finger

One of the most useful features of the GT 40 is the built-in looper. Accessible only with the aforementioned footswitch, the looper gives you the ability to record an unlimited number of 60-second loops and overdubs. If you're a solo guitarist or someone who loves to experiment, you'll enjoy the layering possibilities and freedom that the feature provides.


The Fender Mustang GT 40's USB output jack lets you connect your amp directly to your computer and into your preferred DAW (Digital Audio Workstation). This gives you a high-quality, professional audio recording complete with cabinet simulation. You don't even need to buy a separate audio interface - just plug, play, and record!


How does the Fender Mustang GT 40 sound? In a word: fantastic! While it doesn't have the name-brand speakers of its big brothers the GT100 and GT200, the GT 40's tones are clear and punchy. Remember, the GT 40 is a modeling amp, so its tones are all digitally created. Some players accuse the GT40 of sounding too 'digital' or 'hi-fi', but we disagree with these accusations. Take a listen for yourself!

Public Opinion

On Amazon, reviews of the Fender Mustang GT 40 are overwhelmingly positive. Reviewers acknowledge the huge number of quality tones and versatility of the preset configurations. If you live in an apartment and can't play too loud, you're in good company. A lot of reviews mention just how perfect the amp is for bedroom practice thanks to its smaller speakers.

The Fender Mustang GT 40 is constantly compared with one of our other favorite amps: the Boss Katana KTN-50. You can't go wrong with either. The GT 40 is more tech-oriented has a decent learning curve, while the Boss Katana KTN-50 is a bit easier to configure and understand. However, if you compare and contrast the features, both amps come out about equal. The Boss sounds a little better, but doesn't have the super convenient Bluetooth of the Mustang. Listen to both using the sound samples provided in our reviews and decide which you like best. Remember, everyone's situation is different, so what works for someone else might not work for you. If you need help deciding, leave us a comment and we'll be glad to help!

Conclusion and Ratings

The Fender Mustang GT 40 is a fantastic choice for the tech-savvy beginner or intermediate guitarist who wants a versatile and bedroom-friendly amplifier. With built-in effects, Bluetooth, USB, and dozens more features, the GT 40 will grow with you and provide you with tons of high-quality tones for years to come.

Fender Mustang GT 40: Final Thoughts

Fender Mustang GT40 combo amp
  • Looks:
  • Build Quality:
  • Sound:

The Good 👍

  • Great sounding amp models
  • Very versatile preset configuration
  • Bluetooth, wi-fi, and USB connectivity
  • Fender Tone App unlocks a lot of functionality for controls and presets

The Bad 👎

  • Small 6.5" speakers don't provide enough volume for gigging situations
  • Footswitch sold separately; Micro-USB cable not included