The F.13 Flanger from Alexander Pedals promises a modulation experience that’s part science fiction and part sonic warfare. And yes, it delivers. Get Steppin’ Kid The first of the three modes on the F.13 is probably my favorite, so we’ll start there. I rarely have an actual use for synth-inspired robotic step-filter sounds in the music I play—but I'm still entranced by the sound of them. So when I plugged into the F.13 for the first time, I immediately started there, dialing in a range of different textures. The Depth knob unlocks four different modes, including three varieties of ascending and descending eight-step cycles and a random “sample-and-hold” style setting. I liked the random mode best and had a ton of fun just chugging out distorted power chords with the Rate knob all the way down, the Mix above noon and the Regen knob set fully counter-clockwise. (Try it. You might like it.) And now for an iffy analogy… A few pieces of NAMM content I read fawned all over the third mode on the F.13—and understandably so. Surely inspired by something Frank Zappa dreamed up, Dynamic mode allows you to trigger the primary flanging effect with the intensity of your playing. Imagine that your strings are a tape reel and the harder you play, the harder your finger presses down and the more intense the flange effect becomes. This is sort of what happens in Dynamic mode, but I’ve never played anything like it. Honestly, you’ll probably have to experience it to fully appreciate the power your pick attack truly has. The Rate knob adjusts the sensitivity of the effect, allowing for different pickups or effects in front of the F.13 in your signal chain and the Depth knob controls which direction the flanger sweeps, so there’s plenty of flexibility. But if you’re like me, you’ll probably enjoy the completely whacked out “raygun” sounds best. Hidden Functionality As is true of Most Alexander Pedals I’ve had the pleasure of playing, there’s a bit more than meets the eye hidden below the surface of the controls—and the same is true of the F.13. Now, you might think that the Sweep mode is pretty standard for a flanger. But if you turn the Rate knob all the way down and the Mix knob all the way up, you can use the Depth control to create manual filter matrix style flanging á la the Electric Mistress. Or, if you crank the Mix all the way up and dial back the Regen knob, you’ll find some tasty pitch vibrato. And then, of course, there are all the warm and familiar flanger sounds we love on the positive side of the Regen knob and the pleasantly vocal “inside out” flange textures on the negative side. It’s a very complete arsenal of flanging weaponry. Great Tones. Doing Good If you don’t already know, Alexander Pedals is named after the younger brother of owner and creator Matthew Farrow. Alexander died in 1987 as the result of a rare form of cancer called neuroblastoma. He was only seven years old. So for every Alexander pedal you buy, $5 of the proceeds goes to St. Jude’s Children’s Research Hospital in his memory. So buying the F.13 (or any Alexander Pedal) gets humanity one step closer to ending childhood cancer. And what better reason is there than that? What we like: It’s made in North Carolina, uses soft touch relay switching, sounds great, offers a load of versatility and is built like a tank. (Seriously, it’s about the same color as an M48 Patton.) Plus, it’s priced fairly competitively and comes with the satisfaction of knowing you giving to a great cause. There’s an awful lot to like here. Concerns: None.