Note: Oppo has since stopped making products, although they still support existing ones and will occasionally provide firmware updates. This is sad news as I considered some of their products (the ones I tried) to be among the best. These include their fantastic Oppo PM3 headphone, and this HA2 Amp that we’re about to review. You can still get your hands on one for a decent price, but please be careful who you buy from. You can also check eBay as well for some good deals!
Included Accessories: Power Supply Unit (Rapid Charging Charger)
USB A – USB micro-B data and rapid charging cable
USB A – Lightning data cable (for Apple devices)
USB micro-B to micro-B data cable (for Android and other smartphones)
3.5 mm – 3.5 mm stereo audio cable
Silicone rubber band (2 pieces)
User guide and warranty documents
Built-in Battery type: 3000 mAh lithium polymer rechargeable battery.
Battery Operation Time: Approx. 13 hours for analog source via Audio-in; approx. 7 hours for digital soruces via USB
Charging Time: Approx. 1 hour 30 minutes.
To put it bluntly: The HA-2 is the real deal. As you may know from my other articles, I frequent my local Audio Advice weekly, and sometimes up to multiple times per week. I’m always in there demoing headphones, A/B testing, and taking notes.
Being there so often has allowed me to interact with the guys at the front desk, and more specifically a guy named Chip. Chip is one of their Home Theater specialists, and he really knows his stuff. On top of that, he’s one of the most genuine, personable, and helpful people I’ve ever come across. He’s always down to discuss audio, and it really makes me feel special when he asks ME about my opinions on stuff that has to do with the Home Studio, Headphones, Amps, etc.
We got to talking about the HA-2, and he offered to loan it to me for about a week a long with the Audioquest Dragonfly Red.
Both are absolutely exemplary. The HA-2 is a bit more expensive but it’s worth every penny.
Because I said so. Just kidding. There are a couple of reasons, my friend.
First off, the HA-2 will work with the majority of headphones, and generally it ranges from 16 Ohm – 300 Ohm impedance cans. So yeah, pretty much everything. 😀 What is Headphone Impedance?
The second reason is because it’s output impedance is so low (less than 0.5). This also essentially means that the HA-2 will work with nearly everything you throw at it.
To give you a quick example: My Sennheiser HD600 has an impedance of 300 Ohms and a Sensitivity of 97 dB. In short, because of it’s low(ish) Sensitivity it will require more power from an Amp to reach peak loudness. Related:What is Sensitivity in Headphones?
How much power does the HD600 need from an amp? 20mW to be exact. The HA-2 provides 30mW into 300 Ohm, so it just makes the cut here. Learn more:Sennheiser HD 600 Review.
You can see that 300 Ohms is just about the ceiling for this amp. Being that I wasn’t familiar with the specs, I honestly did not think that the 600’s would sound their best out of the HA-2. I was proven wrong overwhelmingly.
Let’s get into what’s included! We’ll get into functionality in a bit.
What’s in the Box?
The Oppo HA2 comes with:
A Wall Wart and heavy duty premium cable. This is the white cable.
Short 3.5mm to 3.5mm interconnect cable.
Micro USB to Micro USB (For Android)
USB to Lightning (For iPhone/iPad)
2 Bands for your phone, etc.
Let’s move onto features and how this all comes together.
Features & Connections
If there were ever a jack of all trades Amp/DAC, the HA2 would be it. There’s a lot to this thing and it can be overwhelming at first. Thankfully it’s fairly straightforward when you delve deeper. Let’s take a gander.
It’s got a line out jack and a 3.5mm audio in. The line out is labeled AB, and the audio in is labeled C. So basically, use that 3.5mm to 3.5mm interconnect from above. Plug one end into the line out and the other into another source like your phone or laptop. If you’re using it with your phone, switch it to A. If you’re using your laptop, switch it to B. C is just a straight analog in. I don’t use 3.5mm interconnects often, but when I do… Lol. I got nothing. If you have an Android, these are much easier to find than a Micro USB to Micro USB cable. You can also use the line out to a separate Amp if you so desire. Just grab an RCA to mini and you’re golden!
Full Size USB port labeled “A” (for Apple) for use with that USB to Lightning cable that we discussed earlier. Just plug the small end into your iPhone/iPad and the big end into the HA2.
Micro USB port labeled “B” (for Android) for use with the Micro USB to Micro USB OTG cable. As mentioned before, these are a bit harder to find. If for whatever reason you can’t find one and you have an Android phone, a 3.5mm interconnect will always work.
Connection to PC/MAC for use as a USB DAC. This is what I primarily use it for. I just plug the white cable from my laptop into the port labeled B and I’m good to go. You will likely have to download a driver if you’re on PC, so keep that in mind.
Volume Potentiometer. This may seem trivial, but in reality it’s not. This knob feels great, and upon turning it on, it makes a satisfying click with an LED also lighting up green. Satisfying all around!
Gain Switch. This gain switch basically enables the HA2 to become very versatile with a wide variety of headphones. Not only that, but it’s got a really cool mute/fade in function. This means that you won’t blow your ears out if you forgot to turn the volume down before switching it on. After flicking the switch, it starts off low and then gradually reaches peak loudness. A great feature!
Bass Boost. I find that because the bass boost is performed by analog audio circuits, it avoids re-digitization of the signal. This results in a much cleaner and more tastefully done bass that you will immediately notice. Some bass boosts are rather harsh and kind of sloppily implemented. The HA2’s feels natural and adds just the right amount of sub-bass as well as mid-bass impact to the track.
Power Check/Charge Button. On the side, you’ll see 4 tiny green LED lights that show the status of the charge in 25% increments. That’s all well and good but what’s even cooler is that you can charge your phone with the HA2! Just use the white cable supplied. Plug one end into the large USB port at the bottom, and plug the micro end into your phone. Then, hold down the button on the HA2 until the 5th LED lights up Blue. You should notice your phone’s charge meter switch over to a lightning bolt and begin charging. Another nifty feature!
Charge Time. The HA2 gets 12 hours of play time as an analog amp and 7 hours as a digital DAC/Amp. Related:What is a USB DAC?
Portability. Take it on the go or use it at your desktop!
This switch is located at the bottom left of the unit, and is important. If you’re not hearing any sound, the switch may be set to the wrong letter. All you have to do is make sure that it corresponds to what you’re using it for.
A = Apple. For use with the USB to Lightning Cable, Line Out from phone.
B = Android. For use with the Micro USB to USB Cable, Line Out from computer, and to charge the unit.
C =Audio In. For use with Analog Audio Sources such as a portable music player.
With that, let’s get into the build of this thing!
This baby is about as sleek as it gets. It’s extremely attractive and elegant looking, with a rock solid build. When I got my hands on it I didn’t want to ever let it go. It’s that sexy, and just feels really good in your hands. It’s also got one of the most perfect volume knobs that I’ve ever had the pleasure of turning. It makes a satisfying click when turning on and off, and is tight enough to stay in place; i.e. if you accidentally graze it, it won’t move.
If the HA-2 were a female, it would be a mature, intelligent, sexy, and ambitious woman like Keri Russell. For sure.
All of the other ports feel very solid as well. I don’t see this unit breaking down. Ever. There’s not much more to say. You really know where your money went when you hold it. I even dropped it today on accident and it said “That’s all you got?” Lol.
I’ve had it since December of 2017 and I don’t plan on parting with it any time soon. For reference, I just sold a Magni/Modi stack because I rarely use it. I found that the bulk of my listening is done with the HA2, on the road or at home!
Ergonomics & Sound
The best part about this thing is the way it makes your headphones sound. I was floored with the amount of extra detail that I had been missing, and it never comes across in a way that seems forced, harsh, or bloated. It’s one of the smoothest, crispest, most enjoyable experiences I have ever had with an Amp.
There’s really nothing else to say. It’s perfect. The gain switch as mentioned earlier enables this thing to be versatile and flexible enough for just about any headphone. It’s got just enough power to drive an HD600, providing 30mW into 300 Ohm. The 600’s require 20mW from the amp to reach peak loudness as discussed at the start.
I’ve used this thing with plenty of headphones by now and there’s never been an instance of it not providing enough juice. The only issue I had was with the Focal Utopia’s gigantic 1/4″ jack. Using a 3.5mm adapter proved to cumbersome for the HA2 to handle. Not sure what happened, but the sound was missing layers and ended up being a disaster. Learn more:Focal Utopia Review!
Fortunately, with the HD650 and a different adapter it sounded great so I’m not sure what went wrong with the Utopia. Related:Sennheiser HD650 Review!
All in all, the HA2 is extremely efficient and proves to be very versatile with it’s ability to recruit more juice for tougher to drive headphones, as well as that very tastefully done bass boost. What I love most is that it provides plenty of volume with zero distortion to boot. It reaches ear piercing levels and still sounds clean as a whistle. I don’t ever keep it that high, but I have tested it out for a max of a couple seconds just to see how it handled. A NUMBAH ONE! YOU LIKE!
Not only that, but it improves on Soundstage and especially the Imaging of your headphones. You’ll start to notice sounds are spaced out better, to the point of you being able to hear stuff going on you and in back of you. The clarity is almost unreal at times.
It did drop out on me a few times, meaning it just randomly disconnected via USB.I just unplugged and plugged back in and it was fine. Something to keep in mind. As of this 12/13/2018 update, I no longer am having issues with this.
My Video Review
Click to see the HA2!
With all that said, what’s my final grade for this little buddy?
There’s not much that the HA2 can’t or won’t do. It even brewed me a cup of coffee this morning! If you’re looking for an amp that sounds smooth as a baby bottom, comes power packed with plenty of features and connections, is portable and versatile, and has a fantastic build, look no further. The HA2 is the amp for you.
Even though it’s now discontinued, I still think it’s worth at least a look on amazon or eBay. In fact, I think it’s worth more than a look. I think it’s still extremely relevant for an audiophile or casual consumer as well.
Stu is determined to provide the truth about all things audio, and strives to deliver excellent content to you the reader! In his spare time, he likes to fish, paint, play guitar, attend church, take photos, record videos, graphic design, and more. His attention to detail and perfectionist attitude are what allow him to excel, but it can be both a blessing and a hindrance at times.