• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

Review and measurements of Oppo HA-1 DAC & Amp

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
20,600
Likes
25,403
Location
Seattle Area
#1
This is a review and detailed measurements of the Oppo HA-1 DAC and headphone amplifier. It is on kind loan from a local member who literally flew to our nearby airport to deliver it to me! The HA-1 is discontinued but it cost USD $1,199 when it was being sold by Oppo. I just searched on ebay and was surprised that it goes for $1,200 to $1,700!!! Will this be a top find as the Oppo UDP-205 UHD player was? We will find out.

The HA-1 is a hefty unit with a beautiful, high resolution graphical display:
Oppo HA-1 DAC Headphone Amplifier Audio Review.jpg

I wish all DACs/headphone amps above $1,000 came with such a display.

In some respect though, beauty is skin deep as the display is very sluggish to keep up with volume control changes. Worst yet, even though the volume control appears to be digital, it is not. My son has had an HP-1 for a few years and on his, the fancy ALPS motorized control has gone partially bad. One channel is weak until the unit fully warms up. There are a lot of people complaining about this. I found the part online and it costs about $35 which is not bad. What is bad is the thousand screws and subsystems you have to take apart to get to it! Even for someone as skilled as me, it was a nightmare. So be careful in buying a used one if it has this issue. The loaned unit fortunately was free of this problem.

The back panel shows how full featured the HA-1 is:
Oppo HA-1 DAC Headphone Amplifier Back Panel Audio Review.jpg

Everything you would want is there from XLR DAC output and analog inputs to bluetooth. Even today such functionality would be impressed let alone back in 2014 when the HA-1 came out.

All is for not if the performance is not there so let's find out how well it ticks inside.

DAC Measurements
The HA-1 has both fixed and variable output levels from rear "pre-out" jacks. Let's look at the fixed output first:

Oppo HA-1 DAC Headphone Amplifier Audio Measurements.png


This is respectable performance. With SINAD (signal over distortion and noise), the HA-1 barely squeezes into top tier of all DACs tested:

Oppo HA-1 DAC Headphone Amplifier SINAD Audio Measurements.png


The output is above 4 volts so we (my son was assisting me) put the unit in variable mode to dial it down to 4 volts (for XLR output). I was quite surprised at the sudden drop in performance:
Oppo HA-1 DAC Headphone Amplifier Variable Output Audio Measurements.png


We have lost as much as 20 dB in noise and distortion. And this happened while keeping the output voltage the same! Channel balance became much worse too. I am assuming this is due to the output of the DAC now going through the headphone amplifier. Very unfortunate as this makes the HA-1 a lousy DAC with volume control.

For the rest of the DAC measurements, we put the unit back in fixed volume mode. Here is the dynamic range with balanced and unbalanced outputs:
Oppo HA-1 DAC Headphone Amplifier Dynamic Range Audio Measurements.png


This is very good and nicely beats the specifications.

Frequency response is boring in a good way (dead flat):
Oppo HA-1 DAC Headphone Amplifier Frequency Response Audio Measurements.png


Linearity was likewise exceptional:
Oppo HA-1 DAC Headphone Amplifier Linearity Audio Measurements.png


Jitter performance showed issues however:
Oppo HA-1 DAC Headphone Amplifier Jitter Audio Measurements.png


We have two distinct spikes with symmetrical distance to our 12 kHz tone indicating it is jitter at frequency of 6.5 kHz. Some internal timer is ticking at this rate causing these spikes. Turning off the LCD display did not make a difference, nor did making it dance around with spectrum analyzer.

The broadening of the "skirt" around the 12 kHz tone indicates random jitter (with low spectrum) which shouldn't be there either.

Intermodulation distortion showed the classic ESS IMD Hump:

Oppo HA-1 DAC Headphone Amplifier IMD Audio Measurements.png


This is the most extreme version I have seen though. The HA-1 uses ESS 9018 DAC by the way.

Multitone was pretty clean though:

Oppo HA-1 DAC Headphone Amplifier Multitone Audio Measurements.png


Headphone Amplifier Tests
Let's dig right in with power output at 300 ohm at three settings: "Normal" (low gain), "High" and + 6 dB on the volume control (it doesn't stop at 0 dB):
Oppo HA-1 DAC Headphone Amplifier Headphone Out 300 Ohm Audio Measurements.png


The low gain has very little output. Surprisingly, my son has to use an IEMatch even in that mode to get good channel balance with his LCD-X headphones!

Going to +6 dB though produces fair bit of power at the expense of elevated noise and distortion. More on why the curve is jagged later.

33 Ohm load changes the equation thusly:
Oppo HA-1 DAC Headphone Amplifier Headphone Out 33 Ohm Audio Measurements.png


While there is no clipping, distortion rises above just 10 milliwatts or so.

Testing balanced XLR output using all three modes gives us this:

Oppo HA-1 DAC Headphone Amplifier Headphone Out 50 Ohm Audio Measurements.png

I had to expand the graph to the right to encapsulate the whopping 7 watts of output!

The jagged and unusual curve bothered me so I tested the HA-1 with analog XLR input instead of USB:

Oppo HA-1 DAC Headphone Amplifier Headphone Out XLR Input 50 Ohm Audio Measurements.png


As we see, the output is much more sane and conventional. We must be seeing that ESS IMD Hump in there with USB input.

As much improved as this is, the HA-1 is no match for the Massdrop THX AAA 789 when it comes to distortion and clean power.

Output impedance was comfortably low at 1.4 ohm:
Oppo HA-1 DAC Headphone Amplifier Headphone Output Impedance Audio Measurements.png


Channel matching bore witness to my son's experience that the HA-1 is not usable with very efficient headphones:
Oppo HA-1 DAC Headphone Amplifier Headphone Out Channel Imbalance Audio Measurements.png


Listening Tests
I tested the HA-1 with Sennheiser HD-650 first (1/4 inch jack). There was good bit of power but I could get the amp to distort before the drivers got there. Sensation of strong bass was not quite there until the rest of the spectrum was somewhat distorted.

The experience with Hifiman HE-400i was much better. Here, the HA-1 could drive the headphones to the limit with powerful bass response.

Conclusions
The HA-1 must have been a major effort by Oppo. It is a complex beast internally with relays clicking, large LCD, many features, remote control, etc. There are however good number of rough edges both in the DAC and headphone amplifier. If it were being sold for half or a third of when it was new, it may have been a good buy on its looks and functionality alone. But not when it is being sold well above list price with potential for volume control failing.

Given all of this, I can't recommend the Oppo HA-1.

------------
As always, questions, comments, recommendations, etc. are welcome.

As I am typing this, my wife is finishing cooking Lasagna. The smell is amazing and I am hungry so can't think of any reason for you to donate money other than you should!
Patreon: https://www.patreon.com/audiosciencereview), or
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).
 
Last edited:
Joined
Mar 31, 2019
Messages
1
Likes
0
#4
If you still have it could you test the balanced headphone out? I felt like the balanced end got more love from the engineering team, but have no way to test that.
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
20,600
Likes
25,403
Location
Seattle Area
#5
If you still have it could you test the balanced headphone out? I felt like the balanced end got more love from the engineering team, but have no way to test that.
My 50 ohm tests are always in balanced output mode. See the review.
 

D700

Active Member
Patreon Donor
Joined
Dec 21, 2018
Messages
126
Likes
86
#6
...but, but it’s so pretty. That’s state of he art exterior front and back.
 

Music1969

Addicted to Fun and Learning
Joined
Feb 19, 2018
Messages
567
Likes
153
#7
Great review @amirm and happy to read your objective findings matched my own subjective thoughts when I had this years ago.

I didn't enjoy using it's USB input (and therefore DAC). But I thought it was fantastic as standalone headphone amp, using analogue XLR inputs with a good separate DAC.

I obviously agree that today the THX 789 is a much better buy (if you can get one) for much lower RRP but we didn't have that option 3 years ago of course! :)

From memory it's a digitally controlled analogue volume control.
 

trl

Addicted to Fun and Learning
King of Mods
Joined
Feb 28, 2018
Messages
671
Likes
433
Location
Iasi, RO
#8
The low gain has very little output. Surprisingly, my son has to use an IEMatch even in that mode to get good channel balance with his LCD-X headphones!
Hi, I can't understand that, sorry. :( AFAIK IEMatch has a resistive divider inside to lower the output voltage, to better match with sensitive cans; it will also lower background noise.

How can a LCD-X (https://www.audeze.com/products/lcd-collection/lcd-x#aud_gallery_tab_li) to be overpowered by 0.5 miliWatts output power @ 300 Ohms (in low-gain)? That means 0.4 V RMS, right? So in 20 Ohms that would make it 8 miliWatts, correct? Still...way underpowered, even for a sensitive planar like LCD-X:

Maximum power handling: 5W RMS
Maximum SPL: >130dB
Impedance: 20 ohms
Sensitivity: 103dB/1mW (at Drum Reference Point)
Minimum power requirement: >100mW
Recommended power level: >250mW

However, I'll re-read your review later...I'm sure I misunderstand something here. :)
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
20,600
Likes
25,403
Location
Seattle Area
#9
How can a LCD-X (https://www.audeze.com/products/lcd-collection/lcd-x#aud_gallery_tab_li) to be overpowered by 0.5 miliWatts output power @ 300 Ohms (in low-gain)? That means 0.4 V RMS, right? So in 20 Ohms that would make it 8 miliWatts, correct? Still...way underpowered, even for a sensitive planar like LCD-X:
Power is not the problem. Channel mismatch is. Without it he has to have the volume control very low where it has most imbalance. With IEMatch the operating point of the volume control goes up, solving the problem.
 

Willem

Addicted to Fun and Learning
Joined
Jan 8, 2019
Messages
502
Likes
520
#10
What a bummer. Also, I want to repeat a complaint I made before about many of these DACs, and that is that they do not have enough digital inputs. These days, I use the digital outputs of a Chomecast Audio, a Bluray player and a television. If my son had not moved out, I would also have had to accommodate a game console. I don't think this is an unusual array of sources.
For me this was the decisive argument to opt for the Pioneer U-05. I cannot send in mine for a test because I am at the other side of the world, but I am curious how it would test on Amir's bench. There was a French test some time ago with reassuring numbers, but not nearly as comprehensive as Amir's tests.
 
Joined
Feb 17, 2019
Messages
45
Likes
38
Location
Sestri Levante
#13
that LCD... That damn LCD is so sexy, EVERY dac/amp at this price should have one like that.
Hope Oppo will make an "HA-1 mark II" using the 9038 pros.
 

D700

Active Member
Patreon Donor
Joined
Dec 21, 2018
Messages
126
Likes
86
#14
that LCD... That damn LCD is so sexy, EVERY dac/amp at this price should have one like that.
Hope Oppo will make an "HA-1 mark II" using the 9038 pros.
Oppo closed up shop as I recall. I had one of their BluRay players till it’s drive gave up the ghost.
 

anmpr1

Senior Member
Patreon Donor
Joined
Oct 11, 2018
Messages
437
Likes
614
#16
Maybe it was a good purchase in 2014, not today.
Unless one is in the market for something 'collectable', like an old McIntosh or Marantz tube unit, or possibly something unusual from Mark Levinson, like his LNP preamp (that has major wow factor), there's not much sense in paying list, much less a premium, for any used component. Especially digital. Why anyone would do that is something I'll never hope to understand.
 

MRC01

Senior Member
Joined
Feb 5, 2019
Messages
463
Likes
340
#17
Thanks for another great review. It looks the HA-1 line stage, which uses opamps, is cleaner than its headphone output, which is discrete. And it looks like the HA-1 would benefit from a stepped attenuator instead of a pot for volume control. Interesting to see the ESS hump here too.
 

MRC01

Senior Member
Joined
Feb 5, 2019
Messages
463
Likes
340
#19
The HA-1's volume knob is a conventional analog pot and its fixed output setting bypasses the volume control. Do I understand how Amir tested -- both of the first 2 measurements were done using the line stage XLR outputs (not the headphone output)? If so, it suggests that simply putting the volume knob into the circuit reduced performance significantly. I understand how that can increase noise -- but distortion went up too which seems strange. Can running the audio signal through a pot increase distortion as well as noise?
 

JohnYang1997

Major Contributor
Joined
Dec 28, 2018
Messages
1,351
Likes
634
#20
The HA-1's volume knob is a conventional analog pot and its fixed output setting bypasses the volume control. Do I understand how Amir tested -- both of the first 2 measurements were done using the line stage XLR outputs (not the headphone output)? If so, it suggests that simply putting the volume knob into the circuit reduced performance significantly. I understand how that can increase noise -- but distortion went up too which seems strange. Can running the audio signal through a pot increase distortion as well as noise?
Noise may highly possible to come from the pot itself, resistance = noise. Especially if it's high value ones. Even 10kohm pot has 2kohm maximum resistance at 50% which is not low. 50k and 100k pots will be disaster in high performance equipments.
As far as the distortion, it's likely that in order for you to control the volume it has to breakout the optimal routing on pcb. Non ideal routing can cause a lot of problems.
 
Top Bottom