"Due to a move and space concerns, I had to part with my trusty Line 6 Spyder II 212 100w amplifier. Doing some research, I narrowed it down to the Line 6 Catalyst or the Boss Katana-50 Mk II EX. It was back and forth, and I finally pulled the trigger on the Boss Katana. Right out of the box, I could tell that this was an extremely well put together amplifier. The enclosure is rock solid with thick plastic edge protectors all around. The inside of the enclosure is covered in a black felt-like material with absolutely no wrinkles or glue blobs to be found. The knobs, while plastic, feel substantial (as compared to my old Line 6 which felt extremely cheap) and the silk screening on the controls are white over black, so visibility is excellent. Plugging it in and selecting the Acoustic amp mode, the sound was clear and articulate. The Clean amp was more of the same. You can add and remove effects as you see fit. I was really digging this amp. Then I turned it to the Crunch setting. Right off the bat I noticed a significant hum coming from the amp. Going to the Lead and Brown settings made the hum MUCH worse. I switched cables, guitars, where the amp was plugged into to no avail. I honestly thought I had a defective amp, it was that loud of a hum. I was just about to box it up and ship it back when I decided to Google this issue. Low and behold, it is not an issue with my amp but a know problem with ALL the Katana amps. Now it was DEFINITELY going back. But one of the search results stated that there is a simple fix. Intrigued, I read on. This individual stated that hooking the amp up to the Boss Tone Studio would allow you to turn on the Noise Suppressor feature of the amp. I had read a little about the Tone Studio and I quite honestly was not going to play with it at all. I downloaded the program, hooked up my laptop to the amp with a USB printer cable (which is NOT included but should be), made the change and like magic, the hum was totally gone! It was nothing short of miraculous. With the hum gone, I was able to play with the controls on the amp itself and it is a tone monster! But however great the tones from just twisting the knobs on the amp are, the Tone Studio software will allow you to tweak the tones for what I am sure are limitless possibilities. The software is that powerful. I will be playing with it for days, no, weeks to come and I’m sure I won’t have even scratched the surface. This went from a 1-star to 5-star amp simply by clicking a button on the Tone Studio software. I highly recommend this amp."

"I had an original Katana 50 and sold it. With the MkII EX, it's now what I wanted. I actually have two running in linked mode for stereo effects and have a GA-FC-EX attached with an EV-5 expression pedal attached to that and I have a super convenient and flexible guitar rig.

The non-EX is fine, but the convenience of being able to switch channels and effects with the foot pedal and the slick ability to add a second Katana is well worth the extra cost for the EX."

"First: I love this little amp for a couple of reasons.
The clean clarity and the ability of the speaker to withstand gain and crunch.
I love it for directly recording to my digital recorder.
There is zero background noise coming through on the clean and acoustic settings.
A little bit on the crunch settings which I can live with.
I can clean most of that up with my music software.
I bought this Boss Katana-50 as a home studio amp because my major name amp of which I won't name has so much noise it's almost unusable.
If you want something though that play loud this amp, even on the 50w setting and turned up doesn't get terribly loud if you wanted to do anything but record. i.e. jam with friends. Another guitar, bass, drums.
Other than the volume I love it.
Of course you could boost the volume with pedals.
My equalizer boosts the volume enough to make me happy."