A Source Audio UltraWave can allow for 4 different distortions morphing back and forth (with 44 distortion engines available, and any of them able to pair with any other), and routing options such as cascading channel 1> channel 2, or mono> stereo> mono, for huge crunchy sounds. The distortion engines aren't labeled as easily as they are on the AfterShock (they use names similar to the original effect such as Tube Screamer, Muff, Rat, Darkglass), but it tells you what they are as distortion types, such as diode (positive and negative), many varieties of foldback, etc. There's a killer compressor/expander, as well as multiband tremolo and multiband eqing to drive the distortion further. Sequencing can be done, there's LFO, it can do ring modulation, altering the phase offset can give some nice panning, you can get tube driven sounds or synthy, insane overdrive sounds, or you can use it absolutely clean for the compressor. You have 128 presets to fill. Well, 122 since you start with 6 that run the gamut, and there are tons of great presets in the Neuro community, available to download right to the pedal. Always tweak to taste, and start with the output volumes and gain knobs (of which there are multiple across two channels).
All this is done in the desktop editor, not the 4 knobs on the box. This is the most difficult of the Source Audio pedals, but may also be the most rewarding. I'm not much of a distortion person per se, I like overdriven sounds like Jack Bruce on Frank Zappa's Apostrophe is a monster fuzz sound, even bigger than he had with Cream. Larry Graham's sound back then as well is fantastically fat. I like anything that really cuts through the mix. So, I mainly use the UW for clean, but when I do set it through its paces on dirt, man does it deliver! I spent last weekend using it for the Harmonic Tremolo presets made by TriPedalReviews for their demo of it, really enjoying the self-panning tremolo with phaser washes, and this weekend really focused on some crunchy guitar sounds using Tube> Tube cascading into Foldback> Absolute Value (Superfuzz) for one of the tracks. I left the bass with a touch of clean drive, but envelope filter and 4-stage phaser. When I first plugged it in, it still had the guitar crazy QuadFuzz going and it sounded massive on the bass. But lost all of it when playing along. So went with envelope-phaser. But the many EQs could have helped me cut through more, had I wanted to stick with the distortion.
And the Friday night one. Used a different Quad-combination, still a fairly nice distortion sound to me. Especially for an acoustic-electric.