The Boss Katana 100 Gen 3 was my first guitar amplifier in over 15 years. I never needed one after I started using guitar effects processors in the mid-2000s. After all, I used to play guitar while wearing a headset at home, and during rehearsals, I would simply connect the guitar effects processor to the PA to output my sounds. This made it easy for me to create nice effects patches that I could quickly use anywhere without the hassle of connecting a complicated set of pedals and microphones. This changed when I had to play at home with my family, who used an acoustic drum kit.

In this review, I will describe how to use the Katana 100 Gen 3 and my experience using this combo amplifier from the perspective of a guy who mainly uses guitar effects processors with MIDI foot controllers. This review will also serve as a simple explanation of how some of the more advanced features work.

Last year, my kids started playing drums and bass. This inspired me to pick up guitar playing again. Even though I have a 7x50W home theater system, the sound of that system playing the tunes from my guitar effect processors was not able to output enough volume to make it fun to play along with an acoustic drumkit. This made me look into buying a decent and budget-friendly guitar amplifier. After researching, I decided to buy the Katana 100 Gen 3 in November 2024.

I chose this amplifier over others in the same price range because it was the only one supporting acoustic guitar input and, as far as I could see, offered the best effect processing system. I considered the Line6 Catalyst 100 CX because I liked most of the guitar preamp models better and thought the amp and speaker sounded better. Still, I believe the Katana 100 Gen 3 was better for my use case primarily because of the flexibility of the software and the number of effects provided. For my needs, the Katana 100 Gen 3 had everything I needed for small performances and practicing on my own, and with with my family.

The Boss Katana 100 Gen 3 acts like a semi-advanced guitar effects processor inside a combo guitar amplifier cabinet. It can store eight tones (usually called presets on other equipment) spread across two banks holding four channels. 

Pressing the amplifier's corresponding channel buttons switches between the tone channels. The channel button LED lights up to indicate what channel you are using. To switch between banks, you hold the "panel" button for a second. When you are in bank B, the panel button will flash red.

Individual effects can be stored in three different presets indicated by a green, yellow, and red LED. They can be switched between or turned on and off by pressing the corresponding effects buttons on the amp's panel. The level of the effect can be dialed in by rotating the knobs below these buttons. If you want more granular control over all the effects and the order in which they are placed in your effects chain, you must install Boss Tone Studio on your computer and connect to the amp.

The Katana 100 Gen 3 has stereo audio input through a 3.5mm jack at the back of the cabinet. The AUX is mixed into the very end of the signal chain just before the power amplifier. Because of this, it will not be affected by the internal effects. This makes it ideal for practice sessions where you play your guitar using a headset. When I practice alone, I use the AUX input to receive the sound I want to be mixed into my headset without needing a PA mixer. This works great.

Like any decent guitar amplifier, the Katana 100 Gen 3 has a loop send/return port. This port is perfect for connecting external effect processors and looper pedals. Fortunately, Katana has enough effects for most situations, but the option is much appreciated. It is worth noting that the loop send/return is mono. 

I find it strange that the loop cannot be placed anywhere you like in the effect chain; it can only be placed at the very end of the internal effects chain or in specific locations after the guitar preamp. In most situations, this is ok, but I would prefer the option to place it anywhere I want on the effect chain.

When using a looper pedal that can record and loop what you play, you should place the loop send/return at the end of the effects chain to completely control what sound you record. That way, the output from your looper pedal goes directly into the power amplifier and your headphones or speaker. Thankfully, this is very easy to do with the Boss Tone Studio companion software.

The Katana 100 Gen 3 supports two footswitches and an expression pedal on the back of the cabinet. It also supports the GA-FC and GA-FC EX foot controllers, which plug into the same port as the footswitches.

Perhaps my biggest issue with the Katana 100 Gen 3 is that it has no MIDI input. This forces me to use the GA-FC or GA-FC EX foot pedals to control the amp if I want more than two pedals and an expression pedal. This is a shame since I love using MIDI pedals and customizing how I control stuff on my equipment. At the same time, the GA-FC EX offers fantastic functionality in a simple and robust package that meets the needs of most users and comes at a much more tolerable price than most MIDI foot controllers on the market.

The default pedal for the Katana 100 Gen 3, is the GA-FC EX, which offers improvements over the original GA-FC. Both pedals are compatible with the Katana 100 Gen 3, but you have to put on the stickers included with the Katana 100 Gen 3 on the GA-FC for it to indicate the correct switch functionality. The EX version provides additional inputs and has two-color LEDs that indicate the active tone by glowing red in tone mode and the active effect by glowing green in effect mode.

The original GA-FC supports two expression pedals or footswitches, and the new GA-FC EX supports three expression pedals or three footswitches. Please note that you can only connect one switch on each input using a mono cable when using footswitches. You cannot connect a double footswitch using a stereo cable like you can on most other equipment from Boss.

The GA-FC and GA-FC EX have three operating modes: tone, effect, and function. You switch between the tone and effect modes by pressing the effect switch on the pedal. 

In tone mode, you can switch between the four tone channels or use the current panel setting, similar to operating the tone button on the amp's panel. The black text on white labels at the bottom of the GA-FC and the GA-FC EX indicate the tone you select. A red LED on both pedals indicates the current tone. You must long-press the switch labeled "panel" to switch between banks A and B. In bank B, the red LED above the panel switch will blink.

In effect mode, you turn the corresponding effect on and off. Unlike how you operate the effects buttons on the panel on the amp, you cannot use the footswitches to switch between presets (green, yellow, and red). The white text on top of your GA-FC and the black text on the orange labels on top of your GA-FC EX indicate the effect you can turn on and off. A red LED indicates the active effects on the GA-FC, and a green LED on the GA-FC EX.

If you long-press the effect switch, you enter function mode. This mode is indicated by a flashing LED above the function switch. In function mode, you can switch between the functions labeled in small text on your GA-FC EX. If you use the GA-FC you have to rely on you memory.

The GA-FC EX can be daisy-chained with a second GA-FC EX or GA-FC foot controller in what Boss names "Expanded mode." This is done by connecting the second GA-FC to the Expand/Expression pedal three port on the first GA-FC EX, and flipping the mode switch on the back of the first GA-FC EX to expand mode. This mode allows the first pedal to switch between tone presets and the second pedal to control the active effects. This makes for a much better experience on stage or when rehearsing since you don't have to check and switch between tone and effect modes on your pedal. 

To switch between effects mode, and function mode, you must long-press the effects switch on the second footswitch. To make changes in function mode, you must use the second pedal.

What makes the expanded mode even better is that you can use both pedals' external inputs to control your Katana in expanded mode.

Unfortunately, you cannot use the right-most "effect" switches on the first GA-FC or GA-FC EX pedal in expanded mode for anything. If you want to use the button for anything, you must modify the GA-FC or GA-FC EX to connect the switch to one of the external inputs on the pedal.

The GA-FC and the GA-FC EX support external footswitches and expression pedals. The GA-FC supports two inputs, and the GA-FC EX accepts three inputs.

To assign what the first pedal external inputs control, you must use Tone Studio. 

Tone Studio does not recognize whether you use one or two GA-FC or GA-FC EX pedals. Because of this, the GUI has three input options. Of course, if you use the GA-FC pedal, you can only assign two of the three inputs.

The menu for assigning the functions of the external inputs on the first pedal is in the "ASSIGN" tab and then in the "GA-FC/GA-FC EX" tab.

The menu for assigning the second pedal external inputs' functions can be found on in the "ASSIGN" tab and then on the "EXPANDED GA-FC/GA-FC EX" tab.

I love the Boss Katana 100 Gen 3. It has everything I need for my practice sessions. The only thing it's lacking for my preferences is proper MIDI support without requiring the GA-FC pedals. I especially like the sound of the "crunched" amp. I think this is the best tube-amp simulator I have ever played. But then again, I have not tried many. 

After buying the Katana 100 Gen 3, I can finally retire my trusty old rack-mounted guitar effects processors. 

I have been having some regrets, thinking that I probably should have saved up more money and purchased the Katana Artist Gen 3. But after considering all the factors, I think I made the right decision since it almost cost twice as much as the Katana 100 Gen 3.