The iPhone can now take you from ringtones to ringing tone. The pocket-sized IK Multimedia iRig (MSRP: $39.99) builds off AmpliTube's low-latency gear-modeling engine. Combining an app and guitar-slide-sized dongle, a mono 1/4-inch input, and 1/8-inch stereo output, the adaptor converts the iPhone headphone jack into a functional practice amp for guitar/bass/keyboard. You can save/recall 12 preset chains featuring one amp, cabinet, and microphone with three effects (purchased from an expandable selection, with gratis tuner and metronome). Crank a Marshall-style lead amp and modulation pedals and you're ringmaster to a throaty psychedelic circus. Through sliding panels each component mirrors much of its desktop customizability, though don't expect session-worthy fidelity. It delivers a stable, perspiration-free entry to solo jamming and a surprisingly convincing sketchpad for dialing in virtual tone.