Hand-held, go-anywhere digital recorders have taken off in a big way, now that they’re tiny, sound good and have tons of memory potential. Several companies now produce a wide range of models that record stereo audio and there a couple that enable overdubs or multitrack recording – none of those, though, allow an unlimited number of overdubs, each recorded as separate sound files, as the new Korg SR-1 Sound On Sound digital recorder does. And with amp sims and onboard rhythms, there ought to be plenty here to endear it to guitar players.