Patch B5 (acoustic) is the one I use for clean sounds.
If you do a search there are lots of Zoom user patch pages on the web this one is an example
http://thor.prohosting.com/~benkad/.
I've got to admit that i'm a little dissapointed with it and there are probably better sounding/more versatile pedals for the money.
Anyone know which?
If you fiddle with the presets that other people post you can get reasonable sounds, great for messing about at home,but wouldn't consider it for onstage use.
Accuracy,you say? hmm interesting concept..
