I became a believer in Oppo after experiencing their Planar Headphones, which was one of the more satisfying listening experiences I’ve currently had for personal hi-fi audio. But an amplifier is usually taking things to the next level, albeit an expensive one at that. But with the new HA-2 Portable Headphone Amplifier and DAC the performance is worth the comparatively agreeable price.
This is actually no surprise considering the quality Oppo has consistently brought to their growing lineup, from Blu-ray players to premium headphones and pre-amplifiers. I already expected the HA-2 to set itself apart and it certainly does in design, the dimensions of 2.5 x 6.2 x 0.5 inches mirrors that of a Nexus 5 or Galaxy S6, basically an aluminum body that’s wrapped in genuine black leather with contrast stitching. It’s an aesthetic blend that harkens back to the days of classic function and bespoke craft; the power/volume knob alone is a replicated moment of melancholy for people old enough to remember when FM radios and stereo amplifiers were dominated by machined casings and chunky dials.
Connectivity is accounted for with a full size USB A (iPod/iPhone/iPad) and Android smartphone micro-USB B with OTG features (On-The-Go) underneath, a battery monitor and Bass boost/Gain switches on the side, along with two 3.5mm jack headphone output and Audio-in/Line-Out.
Despite the lean exterior the HA-2 has a fair bit of weight in your hand, and feels much heavier than the smartphone that you’d be pairing it to. The reason behind the apparent bulk are the HA-2’s internals which houses an ESS SABRE32 ES9018-K2M DAC that can decode input formats (DoP v1.1 or native) of 32bit/384kHz PCM or DSD (DSD64/128/256), ideal for any device capable of Hi-Res Audio. This also controls output frequencies with unexpected power, easily producing up to 30 mW into 300 Ohm of impedance up to 300 mW.
But how well does it improve the headphone quality? For testing I had the 32 Ohm Oppo PM-2 Circumaural Magnetic Headphones which sits right in the middle of the HA-2’s output power band. These are some of the finest pieces of personal audio I’ve heard, but there’s always room for improvement with a discrete DAC.
I tested it on a PC with impressive results but mainly stuck to the Sony Xperia Z3 smartphone that had apps (Spotify, TIDAL), and a personal collection of songs in FLAC and DSD formats. It only made sense to pair both Oppo devices to a capable mobile device, not only is it a pretty nice setup but it made comparisons much easier too. I briefly touched on the Z3’s capabilities before and found the quality was great but a falls couple steps behind.
With the HA-2 connected, the gentle guitar strums that elevate to a ballad of dominant trumpets in Elton John’s “My Father’s Gun” were richer and more genuine, while going back to D’Angelo’s Black Messiah album for the song “The Charade” came with equally powerful bass riffs and a deep rhythmic drum beat that complimented the studio vocals. Overall, the HA-2 effortlessly picked up the subtle nuances that the Xperia sometimes missed, and made Hip-Hop tracks sound a little more appropriate with the bass boost enabled.
However, the package doesn’t come away unscratched in terms of everyday comfort. Obviously, having a smartphone sit in your pocket and adding a portable DAC only makes things more cramped and potentially damaging for weaker connectors. Things can get cumbersome quickly when you have to connect a smartphone and then add wired headphones to the equation, ending up feeling awkward for listening on the move. Oppo at the very least acknowledges the issue by including a rubber band to strap your two devices together, but that also compromises usability by obscuring touchscreen real estate or functional buttons entirely – they should’ve made life easier and supplied Velcro inserts instead.
But I can forgive the inconvenient approach because the Oppo HA-2 Portable Headphone Amplifier and DAC is everything a dedicated audiophile could ever want in a product. It is incredibly nice, comes built with an amazing DAC chip, and a very potent Class AB amp that can handle the majority of planar magnetic headphones currently available. It definitely has niche appeal before practicality because its already the size of a smartphone that only decodes and improves existing audio sources, however, the results are ideal for proper Hi-Res Audio delivery. In short, this is the amplifier to own for reference-grade quality away from home.