Oppo HA-1 Headphone Amp & PM-1 Headphones Review

Posted on 1st September, 2014

Oppo HA-1 Headphone Amp & PM-1 Headphones Review

OPPO's recent entry into the headphone market was quite a surprise for many fans of the DVD/Blu-Ray manufacturer, so when I had the opportunity to review the latest offerings for StereoNET, I jumped at the chance.

Headphone Amplifier HA-1

Nice and shiny out of the box, the Headphone Amplifier HA-1 is quite heavy for its size. The brushed aluminium housing and 10mm thick front plate really make a statement that this is a quality piece of kit. On the front, a large LCD display, two knobs, and a few sockets for various connections keeps it neat.

The rear panel is splashed with all manner of input and output connections, RCA Unbalanced input and output, XLR Balanced input and output, and the unusual addition of USB, XLR/AES-EBU, S/PDIF and TOSLINK Optical; this amplifier can be used as a DAC and analogue pre-amp, as well as for headphone amplification. If that wasn’t enough, did I mention Bluetooth and iPod/iPhone connection? Well, there's not much you can't do in the connectivity department. I think it's time to plug it in and turn on the power.

The supplied IEC mains lead is shielded, with 1.5mm² conductors. Other accessories included are the svelte remote, 6.25mm-3.5mm head phone adapter and a Bluetooth antenna which screws onto the RP-SMA connector in the centre of the back panel. The display lights up with a simple white-on-black “status” screen showing the selected input, audio format, base gain level and current volume setting. If you prefer something more animated, you have then a choice of 18-band spectrum analyser (100Hz to 10kHz) with red “peak” lines for each band, or “VU” meter mode with -20dB to 5+dB range: The 0dB and above has a red scale, as would be expected in an analogue meter. The display is actually a full-colour, hi-res LCD screen. The fonts are smooth, clean, and easy to read. The numbers may be a little small for those of us better at hearing than seeing however.

Planar Magnetic Headphones PM-1

The PM-1 headphones feel very well constructed. Aluminium cup frames, stainless steel (with lamb skin cushion) head band reinforcing and shadow-chrome adjustable pivots; a real sense of high end and luxury. The wooden box they are presented in is superbly crafted, featuring polished wood and soft lining, and everything fits just so neatly. Attention to detail here is noticeable, and notable, with no plastic in sight.

The headphones themselves have detachable cables to connect to your choice of player. Two options are provided as standard for the connecting cables - 6.25mm stereo plug, with a 3m cable, and 3.5mm with 1m cable for personal audio devices, such as iPod or your mobile phone. Also only as an option from OPPO, is the balanced cable, specifically for connecting the PM-1 headphones to the HA-1 amplifier. For a high end head-fi solution with a premium price, I believe the balanced cable could be included as standard. The connecting plug in the bottom of each ear piece is 2.5mm and fits snugly with a rubber grommet. I did try tugging them with a bit of force and neither side accidentally pulled out, even when I was wandering around with the 4m lead at its full length.

The high quality lamb skin ear pads were fitted to the PM-1's out of the box. Whilst they are quite comfortable for shorter listening sessions, after some hours the lamb skins became a bit too warm. I opted instead for the included velvet ear pads for extended listening. The velvet pads have a much cooler, lighter feel even though the actual weight is not different from the lamb skin ones. Also supplied with the PM-1 headphones is a durable fabric semi-hard carry case and a 3.5 to 6.25mm adapter plug.

Overall the headphones are very comfortable to wear for long periods, but still heavy enough that it's nice to take them off once in a while. In my case, the protruding phase plug in the centre of each diaphragm touched my pinna, or outer ear parts. This would not normally be a problem unless you have big Audiophile ears like me.

Listening Tests - The Source

A first world problem … what source do I connect first? I thought I'd try plugging a USB stick into the front USB socket. No joy - the HA-1 is strictly a “receiver” type device and it must have an external controller such as PC, Media Player or Mobile Phone to tell it what to do. Perhaps an oversight, but ultimately it was never meant to be a media player.

Swapping to Bluetooth connection presented no problems. Connection was established quickly and with no fuss. My Android phone was able to connect to the HA-1 as a media streaming device, and I streamed a few tracks to get a feel for the controls. The comfortably-sized volume knob I found a little stiff, but it is motorised by the supplied RC-HA1 remote. The remote controls both the HA-1 volume as well as source selections. You can also control the Bluetooth, USB and DAC/PC source's next/previous controls. No seek forward or back works, only track selection in this case.

I then connected the XLR inputs to the OPPO BDP-105D's XLR outputs. As the OPPO is now playing the media as the source, there were no problems with connectivity playing music from the USB stick, network streamer or any of the optical discs at hand. XLR connected sources appear slightly louder than the RCA analogue inputs.

Connecting the HA-1 to the PC as an external DAC was a relatively simple process. The HA-1 was instantly recognised by Windows XP, but initially Windows “reported a problem”. A quick download from the OPPO Digital website of the appropriate drivers and a new icon appeared in the tool bar indicating that the HA-1 was connected as an output device.

The Optical, Co-axial and AES/EBU XLR inputs all work as expected. One nice feature would be the ability to connect the audio via HDMI Audio channel, allowing for direct connection to the BDP-105D's SACD digital connection.

Listening Tests - The Music

Listening Sources (in no particular order):

Listening Tests - The Sound - HA-1

Initially, I felt the PM-1 headphones were a little brittle and harsh to the ear, and bass response was a bit shy with noticeable lack of output below 100Hz. Over the first several hours however I noticed the overall sound was improving, as would be expected as the diaphragms break-in. I decided to leave them playing for a couple of days – as it was obvious they would improve with a few more hours under the belt.

Using my familiar Ultrasone HFI-580 headphones, I began by trying out all the functions and modes of the HA-1, to get a base reference for the sound of the headphone amplifier itself. I must say I am very impressed with this unit. It has no sonic flaws that I could discern at all. Switching between different inputs and modes causes a small flurry of relay clicking, and only the slightest audible click in the headphones themselves.

I streamed music over the USB as well as playing discs directly from the BDP-105D. There was only a slight difference I observed in that streaming digital seemed to have slightly cleaner sound than playing a disc through the analogue or digital of the Blu-ray player. This says more about the BDP-105D than it does about the HA-1.

Other than the lack of being able to play directly from a USB flash or hard drive, the HA-1 is a flawless piece of gear, and at the price point, very hard to equal, let alone exceed in performance and features.

Listening Tests - The Sound - PM-1

By now, not surprisingly, the PM-1 headphones had benefitted from the extra hours of talking to themselves on the test bench. Overall they have a very clean sound, with smooth mid-range response and crystal clear highs. After about 80 - 100 hours, the bass was as it should be - full and detailed, but not overbearing or prominent. This extended run-in time also brought more life to midrange and high frequencies, exhibiting a nice airy sound with great micro dynamic detail, as well as very good resolution of low level sounds.

Even at higher levels listening, the PM-1 headphones do not lose their composure. At similar output levels the Ultrasone HFI-580 headphones simply cannot match the PM-1.

ALBENIZ's ‘Castilla’, and the following track ‘Austurias’ on the XRCD24 is audibly compressed compared to the Decca Vinyl pressing of ca.1969. This is not unexpected. It’s a great reference track however and the strings being plucked or hit, and people moving around in the orchestra are clearly heard among the instruments. Little bumps and plucks out of time are clearly audible. There is a hint of brightness in the upper mid range on this track, which can be typical of orchestral recordings, but might indicate some phase anomalies somewhere in the system.

FIONA APPLE’s album ‘Tidal’ I was introduced to through an article entitled “Ultimate Midrange Shootout”, and over the past few years I have listed to this album on many systems. The PM-1 / HA-1 combination was a real revelation with this album. Very clean and clear, the chosen tracks took on a whole new life for me. Vital and detailed; so many nuances which had been hidden previously. I think I'll be exploring this album even more closely in the future.

DEEPER BLUES’ ‘Dig the Hole’ album, I had actually not heard before Ed loaned me a copy. This album has full bass, clean highs and is fun to listen to, showcasing the brilliant bass playing of Lane Baldwin. This is a dynamic recording that enjoys being played loud, not an issue for the PM-1 headphones.

“Listening” to a movie sounds weird, but it does give a good spread across sound effects, music and plain dialogue. Once again, I thought the bass was a bit shy at first, but realised that it was just in the correct phase / timing rather than being too late or early if you have a separate LFE channel or associated pseudo-surround processing that I’m probably more used to.


Great sound in context, seems to carry more weight in the mind, and I found myself actually listening to whole albums rather than only selected tracks. The sound was not fatiguing at all, even after three or more hours sitting, wandering around the office and doing the normal day-to-day things.

Overall, the HA-1 and PM-1 Headphone and Amplifier combination far exceeded my expectations in sound quality and features for headphones, and anyone who invests in this headphone set should not be disappointed.

For more information visit OPPO Australia.

    Posted in:Headphones Headphones Headphone Amps Over / On Ear
    Tags: oppo  ha-1  pm-1  interdyn 

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