It kills the dynamic a lot. Also it makes the high end "rounded". The roundness characteristic might be the reason why John Mayer uses it...

I tried as many boosters as I could and definitely the Katana is the best one! Great sound and boosts my tone doing an excellent addition to my gear.

Got this pedal to use as a quick volume boost when I go to play a lead. It works just fine but the button to turn it on is so loud it's unusable for my purposes. Maybe in a full band with bass and drums that loud click would be lost, but when it's just two of us playing relatively low key, that loud click sounds like an explosion. Surely they could have designed a pedal with a quieter on/off button? I'm really impressed with my other Keeley effects pedals but this one was a disappointment.

My interest in the katana began with my love for John Mayer's lead tone in the JM Trio, which is essentially a strat into a katana into a TS808. In my research I couldn't find anyone with anything negative to say about the katana. Everyone says it's awesome, and many reviewers say its their favorite pedal on their board. Now having bought my own, I understand why. This pedal makes everything sound better. I run it in front of my TS808 like Mayer, and it just sings. The sweetwater exclusive pink paint job is the bee's knees, looks as beautiful as it sounds. BUY ONE NOW.

I can't say enough about this pedal, it's yet another home run from Keeley (and sweetwater). I personally love the color, and it's even better in person.

As far as the actual function of the pedal, this thing rocks, whether you're boosting into other pedals or straight into your amp it has the perfect transparent tone. And have I mentioned it's whisper quiet?? It makes 0 noise while giving tons of boost, it's fantastic.. get one while you can.

Clean, transparent boost or add a little grit. Simple. Perfect. Highly recommend.

I don't think any pedalboard would be complete without this. I love keeping a clean slightly overdriven tone with zero distortion. It gives my natural tone a super clean punch without anything extra that makes the guitar sing! I think this is the perfect "church" tone in itself. With that said as a blues player I think it bridges the gap perfectly between no effects and my Ibanez Ts9 on low gain settings. Just the opposite, add the 18volt boost to give your metal distortion pedal some extra power to scream for high gain applications. Best pedal I have and money well spent.

I love this pedal. It gives you nice boost without introducing noise in your signal chain. As a bonus, the new special edition Pink finish stands out on your board. Well built in the USA. What's not to love about this pedal. Get one!

I've owned a katana mini before and I liked it, but there's something about the original design and size that I personally like more. Does exactly what it says it does. Beautiful clean boost and just makes your signal louder. Pull the knob and adds just enough grit to push your amp into some nice breakup. Keeley nailed it and the pink sparkle is actually very pleasing to the eye.