Never mind the source file, why does mobile music lack sound quality? Style headphones are just that–style over substance–while iPods, MP3 players and phone/music player variants are barely satisfactory. This situation can be improved, however, by inserting a headphone amplifier between your player and the headphones. Just Audio has two on offer: the µHA-120 (55 x 25 x 85mm) and the slightly larger AHA-120 (80 x 28 x 125mm), the latter shifting at the weight of a couple of mobile phones, the former around half the weight of a single phone.
Simple, solid and well built, both feature a rechargeable battery that lasts around 18 hours, a rotary volume knob, a headphone socket, source (iPod, MP3 player, tape machine, etc.) and a mini-USB charge port. The AHA-120 also features a rotatable impedance knob to precisely match your headphones to the unit.
I played a range of pop and vocal jazz through the Sennheiser PX 100 (30 [pounds sterling]), HD650 (300 [pounds sterling]) and HD800 (1,000 [pounds sterling]) headphones via the ubiquitous iPod Classic 80GB.
Let’s start with the juHA-120. Despite the price, my first mistake was to equate size with quality. This tiny amp had a spacious, airy upper mid-band with a meaty bass that provided immense transparency, making the quality difference between the PX 100 and the HD650 plain. What shocked me was how well it drove the superb HD800 headphones–these are tough to get going–and how dynamic the sound was.
Moving to the AHA-120: the better-quality components plus the useful impedance control improved the general performance of the PX 100 headphones, giving them a more natural open presentation. The HD650 impedance was moved from 32 to 300 as the soundstage broadened, while the upper midrange became more complex. Vocal harmonies revealed their layering while instrumental separation provided a busy, yet clear, delivery. The play on the HD800 was so good that both the headphones and AHA120 highlighted the inadequacies of the mastering on the pop chart tracks, their compressed bass and peak-limited vocals, while bathing in the top-quality mastering of the jazz vocal: the fragility of the treble and the metallic attack of the acoustic guitar.
If you find the idea of portable grooves frustrating, book a demo of either or both of these Just Audio units. they have the power to restore your faith in mobile music.