Oppo’s recent achievement in the audio universe has not gone unnoticed. I am almost certain they’ve made most other audio brands duck and run for cover, give up their lunch money and require a hall monitor to escort them safely to and from the restroom. These guys don’t mess around.

The HA-1: In “A Class” of its own

Never before have I come across a DAC and amplifier combination that has as much to offer as this HA-1 from Oppo. Balanced output USB DACs in the $1000-1500 price tier are not at all common, even more rare to find one that doubles as a moderately powerful Class A amplifier with DSD capabilities for only $1199. I can dedicate a full report just to the objective, factual information regarding what the HA-1 is capable of, but I won’t and will draw clear lines between what I feel to be important objective information, as well as my subjective opinions:

The build quality on this machine is nothing short of stellar. At a hefty 13lbs, the unit feels incredibly heavy and solid. One thing that I noted immediately was that mesh heat-vent window on the top of the unit. I am not so sure this was a good idea, as it will allow dust to settle into the innards of the product and make it near impossible for me to clean if need be. I recommend you find some type of dust-proof material to set on top of it. As it turns out, this amp can run fairly hot after being active for a while. In the image below, you can see dust particles annoyingly attached to the inner surface of the perforations on the grill vent. These are so hard to clean properly and near unavoidable.

Fully Balanced XLR 4pin outputs along with a purified and true balanced signal from the Saber 9018 allow for raw, unbridled bass weight that is almost perfectly suited for usage with the PM-1 (Oppo’s recent Planar Magnetic headphone release). The use of balanced components allows for a slight noise reduction and in my experience tends to add a bit of bass weight. The interesting fact here is that Oppo did not go the lazy route. They made a complete balanced signal from start to finish; even the non-balanced output is derived from the balanced components inside. What does that mean? It means the HA-1 is one of very few fully balanced DAC/Amp combos available. Oppo claims the balanced output pushes 4 times the power (double the voltage) of the single ended output.

The 9018 DAC chip

The Saber 9018 DAC is a raw and pure chip most of the time, usually offering a more clinical and reference flavored candy bar for your ears to enjoy. Musicality and warmth are generally not terms that go along with the 9018. In the case of the Burson Conductor SL, which uses the exact same 9018 chip, the sound is indeed raw and pure, yet through the Oppo HA-1 the sound is a bit colored and less sterile. Burson has implemented the 9018 better than Oppo, as switching up between the two instantly show cases more depth and clarity on the Burson Conductor SL while retaining that pristine, uncolored clarity The HA-1 lags behind a bit and it is very clear that the core tonality of the HA-1 is not based off of the 9018 DAC, it is more of a collection and sum of all the rest of its parts with the 9018 being the minority. How do I know this? Well, pretty much every other DAC that uses the 9018 is sterile and clinical, yet the 9018 is noticeably more colored through the HA-1.

The 1793 DAC in the Burson side by side with the HA-1 using the 9018 sound near indistinguishable. The only real difference is that the Burson Conductor SL has the edge in stage depth; also that it has less width presence than the HA-1. The 1973 chip is not as clear or dynamic as the 9018 with the Burson Conductor SL, so I found it very cool that headphones with smaller soundstages really made the HA-1 and the 1793- Burson sound identical. I failed blind a/b testing a few times, attempting to differentiate which amp was the Burson and which was the HA-1.

Using Foobar2000, a freeware music program that caters to audiophiles, the user can set single keystroke hot-keys to swap between outputs. While using a typical stereo splitter interconnect that lets me plug one ¼ headphone adapter into two sources, I was able to swap between the track playing through the Burson and the Oppo with a single press of any key I desire on my keyboard. It became wildly obvious that the HA-1 suffered a bit from a lack of spaciousness in the depth of field of the stereo imaging, which is plentiful in the Burson. Sound stage width is a serious issue with the Burson and more than abundant in the HA-1, which has a much more well formed presentation with better separation qualities from left to right. While using the 1793 inside the Burson, the HA-1 sounded identical in almost every way. So much so I couldn’t tell which source I was listening to with blind testing. However, when the 9018 was inside the Burson, I could easily tell which was superior and which wasn’t. The HA-1 falls short compared to the Burson using the same 9018, but the HA-1 still retained better stage width and separation qualities.

I spoke to Oppo on the DAC implmentation and this is what they had to say regarding the implementation:

HA-1 is our fourth generation of the ESS Sabre DAC implementation (First: BDP-83SE, Second: BPD-95; Third: BDP-105). The implementation of the ES9108 Sabre Reference DAC chip in the HA-1 reflects the experience and skill of the OPPO designer in mastering this excellent component. The original Sabre DAC reference design board provided by ESS is very “pure” and measures well. We successfully carried out the reference implementation in the BDP-83SE and BDP-95 Blu-ray player design. Some audiophile users and reviewers comment on early Sabre DAC implementations as although very detailed, however “too analytical”. We have developed special ways to address this concern and the innovative use of the ES9018 DAC chip is among the techniques we apply to the HA-1 design. We also developed our custom-made capacitors to improve the sound of the Sabre DAC. Although we cannot disclose and explain all our design secrets, but please be assured that each design consideration in the HA-1 has very valid reason behind it. We went beyond the reference design in order to balance the raw benchmark performance and actual listening results. We believe we achieved this design goal quite well with the HA-1

Recommendations: If you own a Sennheiser HD800 or similar spacious headphone, you might want to opt for the HA-1, as the larger width and good separation qualities will accentuate the natural presentation the headphones offer. However, if you have a more intimate headphone, perhaps something more like the Beyerdynamic T1, Audeze XC or the Hifiman HE500/HE560, you will probably enjoy the Burson more.

Sub-Frequencies

Clearly, this amp is set up to be as well rounded as possible. Articulation tends to lead to a refined sound, which this amp is only just capable of touching on. That is a good thing, so don’t take that as something to avoid. This is a “can do it all” amplifier without much to complain about. With regard to bass in general, the experience is still top tier for the price range in terms of clarity, however the texture seems to stay the same; a bit soft around the edges but still solid for the most part. On a flat neutral EQ setting, the HA-1 offers entry level moderate quantity on the low end and I find myself always wanting my software bass booster active at +5dB. Anymore than that and it seems to lose a bit of focus and control. Pushing it to +10dB probably isn’t the best idea but surprisingly the HA-1 handled it well without over emphasizing and chaos ensuing. It handles Foobar2000s ‘RealBassExciter’ better than any other DAC I have ever used in any price tier. Typically, beyond the +5dB frontier, every other DAC I’ve ever experienced loses that control factor and the bass becomes watery and flabby, almost puttering like a car running out of gas. The only other DAC that comes close would be the Apex Glacier. Despite that DAC having a lot less clarity than the HA-1, it was still able to remain solid up to certain points of bass boosting, all be it still beyond what most other DACs were capable of.

Summed up, this amp is not for bass purists, but will be able to handle the likes of the Sennheiser HD800 low end nicely while adding a bit of coloration. If you want reference and purity in the bare sense of the word, the 9018 in the Burson is what you should be after. If you want a more musical approach that is more rounded, the HA-1 is for you. Bass heads will enjoy the Oppo much more, as it is capable of more quantity without feeling overly thin, warped or stretched beyond that +5dB mine field horizon.

Recommendations: The Audeze XC, LCD3, Oppo PM1 and Stax 007 ( when using the HA-1 as a pure DAC out to my Woo Audio GES ) the Bass is exceptionally well tailored for fun and musicality, but retains very good ( not excellent ) bass quality. Headphones with a less reference and clinical sound will pair very well with the HA-1 . However, sets like the HD-800, AKG K812, Beyerdynamic T1 and MrSpeakers Alpha Dog will benefit more on the low end from more bass purity than what the HA-1 can offer.

The Oppo PM-1 Headphone is by far the best meshing of any headphones I currently have or have yet heard with the HA-1. No doubt, Oppo has purposely tailored the HA-1 to combo with the PM-1 to the best of it’s abilities…and it certainly does just that. The experience is simply fantastic in every way. As any audio junkie is aware of, it is immensely difficult to find that perfect combination of components that click together perfectly. Once achieved, the experience is nothing short of sublime, everything accentuates everything else. This is what Hifi is all about, what a fantastic combination of headphone and amplifier in this PM-1+HA-1 pairing. The Lawton Denon D7000 also paired incredibly well with the HA-1, these are two headphones never to skip over if you own the HA-1.

Click on next page for vocal and mid range impressions…