IK Multimedia is making it easier to bring a mini music studio on the road, especially if you have a newer iPhone. It just introduced an iRig Micro Amp that produces 15W while touting a USB interface, giving you a reasonably powerful yet portable amplifier with tone processing on iOS devices, Macs and PCs of all stripes. You don't need a headphone jack here, folks. It's larger than the company's earlier Nano Amp, but still compact enough that you can toss it in your backpack for impromptu practice sessions.