Reviewing OPPO's PM-3 closed-back planar magnetic headphones along with their HA-2 portable headphone amplifier and DAC is an interesting task for me. I have been what I would characterize as “upper mid-fi” for a very long time. Beginning in the early eighties, I moved from “starter” home audio systems to nicer equipment fairly steadily over a decade or so. I was digital almost from the beginning of my serious listening period—in 1985 I purchased a Technics SL-P2 compact disc player and the music I love most was generally recorded during this early digital age.
One if the greatest positives for me of the original Apple iPod was that it would store and play back uncompressed AIFF files (very few other MP3 players of the age gave you this option). This AIFF support meant that Apple’s vaunted “one thousand songs in your pocket” was closer to a hundred songs for me, but I didn’t care. For me, it was still a far more efficient way to carry my music than with ten or more compact discs.
I’m an OPPO Digital fan. I’ve owned their BDP-95 Blu-ray player for about three years now and have been extremely pleased with its performance and flexibility. I also had a chance to listen to a prototype of OPPO’s first headphones, the PM-1 planar magnetic headphones, over a year ago at International CES 2014. Harris Fogel’s June 2014 review of the production PM-1 is here: http://maceditionradio.com/node/6007
My headphone choices have varied over the years. I swiftly came to detest the headphones that were included with my early Sony, Aiwa, and Technics mobile playback devices. Unlike Mac Edition Radio founder Harris Fogel, I have also never been a fan of in-ear earphones—I’d like my music over my ears, thank you very much. I started first with moderately priced but at least slightly better than stock Sony headphones. The first at least somewhat differentiating headphones I purchased were Koss’s original Porta Pro on-ear headphones, whose light weight, decent bass, and general toughness were a revelation in the mid-1980s. Sometime in the early 1990s, I purchased a set of the iconic AKG K240Ms, for many years the “studio standard” when there was such a thing. I still own and use both the Porta Pros and the K240Ms.
Because of all this, I was definitely predisposed to like the combination of the PM-3 planar magnetic headphones and the HA-2 portable headphone amplifier when I first heard it during International CES 2015. What I was not ready for was how much I liked this combination and how much of an emotional response it generated for me. I have grown somewhat suspicious of the CES reality distortion field, so I was quite enthused when review copies of the PM-3 and HA-2 arrived at my door last week.
OPPO’s packaging always seems to do a great job of reassuring the buyer that she or he has made an excellent purchase decision. The PM-3s come in a well-constructed square black box, with only an OPPO logo to identify them. Inside is a black selvedge denim carrying case, a user manual, a 3-meter detachable cable (1/8 inch with 1/4 inch adapter) and 1.2 meter 1/8 inch detachable cable with mic and controls for iOS devices (OPPO offers the option of either an iOS or an Android-centric cable).
The HA-2 comes in a similar but smaller square black box, with a user guide, charger, USB A to USB micro-B data and rapid charging cable, USB A to Lightning data cable (for iOS devices), USB micro-B to micro-B data cable (for Android and other smartphones), and 1/8-inch stereo audio cable all included.
The PM-3s show a significant resemblance to the “bigger brother” PM-2 and PM-1 designs, with much of the attractive materials used similar to the PM-2. They are smaller and lighter; only 320 grams without cable versus the 385 grams that the PM-2 weighs and the 395 grams that a PM-1 comes in at. The driver size is also smaller and differently shaped—a 55 mm circular driver versus the 85 mm by 66 mm oval driver used in OPPO’s larger headphones. What I see as the most significant difference is that the PM-3s are the first OPPO headphones to operate on the closed back acoustic principle. In something that should appeal to buyers more conscious of fashion, the PM-3s are available in either white or black. I’m somewhat of a traditionalist—I asked OPPO's Jason Liao for my testing units to be the black ones.
The HA-2 is almost exactly the same height and width of an iPhone 6/6s/7, though it is substantially thicker. It weighs in at 175 grams and its aluminum chassis is wrapped in black leather. On the top of HA-2 is a power/volume knob with a green power indicator, an audio-in/line-out jack, and the all-important headphone jack. On the side from top to the bottom are a power bank indicator (the HA-2 can provide USB power to an external device), a four-step battery level indicator, a battery check button, a bass boost switch, and a gain switch. On the bottom is a source selector, which chooses from USB A, USB micro-B, and analog audio in. Next to it are two USB connectors—a USB A and a USB micro-B.
Inside the HA-2 is a 3,000 mAh lithium polymer battery that charges quite quickly from the included chargers. That battery powers the HA-2’s ESS Sabre32 Reference ES9018-K2M DAC, a mobile version of the ES9018S used in OPPO’s HA-1 $1,199 desktop headphone amplifier. The Sabre is capable of Pulse-code modulation (PCM) sampling frequencies from 44.1 kHz to 384 kHz, at 16-bit, 24-bit, and 32-bit resolutions. It can also handle Direct Stream Digital (DSD) sampling frequencies of 2.8224 MHz (DSD64), 5.6448 MHz (DSD128), and 11.2896 MHz (DSD256, native mode only).
Almost all of my testing was done with an iPhone 6 and much of it was with AIFF files, though I also tested with some FLAC files. I tested both at home and while walking outdoors: I found that the sound isolation of the PM-3 was so good that I was often able to turn the volume down—something that should help any headphone listener's hearing over time. I listened in two basic setups: the first was from the iPhone 6 analog output directly to the PM-3s while the second was via the iPhone Lightning connector to the USB A input in the HA-2 and then from the HA-2’s headphone output to the PM-3s. My listening was to the music I love: ranging from Joe Satriani’s “Flying In A Blue Dream” to Anita Baker’s “Sweet Love.” I built a playlist of over 40 tracks that I felt would be representative and I listened to those songs in both setups.
I think one of the first questions that most folks interested in PM-3s will ask is “do I really need the HA-2?”. I believe that the PM-3s are very satisfying on their own, but you do run up against the limitations of whatever amplifier the mobile device is using. OPPO is polite on their website; they merely state that “the smartphone's built-in DAC and headphone amplification circuit are often cost-constrained.” I’ll be blunt—OPPO is almost certainly spending at least an order of magnitude more on the DAC and headphone amplification than Apple and other smartphone manufacturers are. The HA-2 should notably improve the sound of the PM-3s and it most definitely does. I found that the difference was most obvious when listening to bass-heavy or bass-centric music, where the power requirements of the PM-3 strain the iPhone’s headphone amplification circuits.
Of course, OPPO will happily sell you the HA-2 alone if you have already made a commitment to some other pair of headphones. I spent some time with the HA-2 and my AKG K240Ms and enjoyed the results—there was an increased sense of detail and precision. With a recommended headphone impedance range of 16 Ohms to 300 Ohms, the HA-2 can easily drive most high-end headphones, and I never came close to using the top of its volume range. Switching between the Low and High gain settings allows quick matching to vastly different kinds of earphones and headphones.
The short form on the PM-3 and HA-2 combination is that I hear things that I have never heard before in songs that I thought I had previously plumbed. An excellent example is Simple Mind’s “Real Life,” the title track from an album recorded, mixed, and mastered with what was fairly state of the art digital equipment in 1989 and 1990. Over-engineered and overproduced (of course) “Real Life” has a ton of sonic detail and driving the PM-3s from the HA-2 reveals much of it.
In an entirely different vein, Aimee Mann’s intimate “Calling It Quits” (from 2000's carefully recorded Bachelor No. 2) shows off the OPPO combination’s effortless musicality. Aimee is right there with you as she sings her sad tale about “where get-tough girls turn into gold mines.”
OPPO's combination also did good work with notably older recordings, treating them well while getting every last bit of fidelity out of them. Del Shannon's 1961 hit "Runaway" gained notably from the HA-2's excellent Sabre DAC, but it never made me feel that it was trying to create more than was actually there.
At $399 for the PM-3 headphones and $299 for the HA-2 headphone amplifier, I see this combination as an absolute bargain. They are a superb way for the enthusiastic listener who senses that there is more to hear to enter the upper ranges of audio and also one of the best ways to take exceptionally high fidelity "on the go." Very highly recommended.
John Mulhern III, posted 3/22/2015
For more information on the Oppo PM-3 Closed-Back Planar Magnetic Headphones visit: http://oppodigital.com/headphones-pm-3/
For more information on the Oppo HA-2 Portable Headphone Amplifier and DAC visit: http://oppodigital.com/headphone-amplifier-ha-2/