ALO Audio has unveiled its new Pan Am headphone amplifier and USB DAC for the iPod, iPhone, and iPad. Powered by a pair of new or “new old stock” vacuum tubes, it offers 24 bit/ 96 kHz capabilities thanks to a Wolfson DAC, USB, 3.5mm stereo and RCA stereo audio inputs, both 3.5mm and 1/4” stereo headphone output jacks, a front-mounted adjustment knob, and an optional battery pack good for 10 hours of listening. ALO Audio’s…