This pedal is based on the company's Lo-Fi Loop Junkie, with its old-school vibrato and chiming compression, which only applies its magic to the looped sound, not your real-time guitar signal. This is why Z.Vex has produced the Instant Lo-Fi Junkie (minus the looping).
Of the knobs on offer, the Comp/Lo-Fi control acts as a blend: to the left you get punchy clean compression (ideal for boosting your picking), and to the right you get lo-fi modulation; anywhere in between is a mixture of the two sounds.
The Tone control only effects the sound of the modulation (it doesn't do anything in Comp mode). On top, there's a three-position mini-toggle for changing the mod's waveform.
You get a sine wave (gentle sweep), triangle wave (more pronounced) or a square wave (straight up/down sweep).
The Junkie works on distorted sounds, but you'll get the most out of it on clean/semi-driven settings. We found our sweet spot (a dream-like warble similar to the sound you get from a stretched cassette tape) with the Comp/Lo-Fi control at about three-quarters with the sine wave modulation shape.