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THX Onyx Review (headphone adapter)

amirm

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#1
This is a review and detailed measurements of the THX Onyx MQA DAC and Headphone Adapter. Company was kind enough to send me one prior to its announcement today. The Onyx costs US $200.

There are a lot of "dongles" out there but the Onyx is the first one to bring good bit of class to the category:

THX Onyx review headphone adapter dac amplifier portable.jpg


As you see, the device is a bit long but also sleek. An integrated USB-C cable has a large custom strain relief and is made of lovely silicon. Better yet, it has a magnet at the end which mates with the same on the device itself to give a mechanism to wrap your headphone cable around:

THX Onyx review headphone adapter dac amplifier portable USB-C.jpg


I didn't have a use for that but would play with it for hours, attaching and detaching the magnetic latch! :)

There are three LEDs that show the various status of the device. I didn't care to memorize what they do so I leave it up to you all to figure out.

The Onyx uses the THX amplification module which became famous in desktop configuration. At the time, it broke all records as far as low level of distortion and noise. Interestingly enough, the marketing material talked a lot about its low power requirements (due to lack of need to bias the output stage) but all the products based on it were desktop, powered units. Later, a headphone with the amplification was released but no stand-alone such as we see here. While I did not measure the power consumption, the Onyx ran cool to touch after some use.

THX Onyx Measurements
As usual, we start with our dashboard:
THX Onyx Measurements.png


Distortion is at the limit of audibility which is to say it is transparent. With a bit of noise, SINAD slides to 108 dB which while not class leading, is still excellent:

Best portable dongle headphone phone.png


Dynamic range follows suit:

THX Onyx Dynamic Range Measurements.png


Dongles tend to show a lot of spurious but usually inaudible tones in our jitter test. Onyx is the same although it is much better than many dongle including the free or $9 ones you get with your phones:

THX Onyx Jitter Measurements.png


At -130 dB, the spikes are 15 dB better than best case threshold of audibility so definite a problem for the eye but not the ear.

Multitone test shows the low distortion levels:

THX Onyx Multitone Measurements.png


The filter is a rather slow one:

THX Onyx DAC Filter Measurements.png


Most important measurement for a portable dongle is not the above but availability of power. So let's start with 300 ohm load:

THX Onyx Power into 300 ohm Measurements.png


Nice to see no clipping. Output power is limited by 2 volt output which is almost the best we get in this class product without resorting to differential ("balanced") output:

Best USB headphone adapater review 300.png


Switching to 32 ohm load though, allows the Onyx to shine more with its high current delivery:

THX Onyx Power into 32 ohm Measurements.png


Best USB headphone adapater review 33.png


Testing for load dependency we see an amplifier that simply doesn't care (in a good way):
THX Onyx Power into 12 to 600 ohm Measurements.png


It only goes into protection (tall lines going left) when impedance is at 12 and 16 ohms. Above that, there is no clipping at all.

THX Onyx Headphone Listening Tests
With my Sennheiser HD-650, the Onyx was capable of driving them to very nice loudness with superb fidelity. It is nice to be able to crank up the volume to max and not notice any distortion. For normal listening though, I had the volume down -6 dB (software DSP volume in my Roon player).

Switching to Drop Ether CX low impedance headphone resulted in similar experience. Again, there was no distortion and plenty of volume although maybe a hair less than I had with Sennheiser HD-650.

Conclusions
THX's take on portable headphone adapters is up the industrial and look and feel of the product. And bring it under a much more recognized brand name. Its subjective and objective performance are near or at the top of the class. The only two misses are rather high price of $200 and lack of balanced output for very inefficient headphones.

Overall, I really like the look and feel and execution of THX Onyx and such, I am going to put it on my recommended list.

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

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RickSanchez

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#2
There are three LEDs that show the various status of the device. I didn't care to memorize what they do so I leave it up to you all to figure out.

According to the Gizmodo article ...
The Onyx itself will actually let you know the quality of the track you’re listening to with its set of three color-changing LEDs. Blue is CD quality or slightly above, yellow is high resolution, red is Direct Stream Digital (what Sony and Philips used for Super Audio CDs), and magenta is for max quality MQA certified tracks.
 

respice finem

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#5
Nice... and still small, though it looks large until you look at the USB-C. Some features, as always, come at a price...

BTW I got an idea of a "luxury feature" for ASR: clickable comparison charts? (click on 2-3 items and compare the reviews).
No I'm too "lame" to code it, sorry ;)
 
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amirm

amirm

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Thread Starter #7
BTW I got an idea for a "luxury feature" for ASR: clickable comparison charts? (click on 2-3 items and compare the reviews).
No I'm too "lame" to code it, sorry ;)
You and me both! :) But we are getting to the point where we need custom comparison tool. I will create a new thread for it and see if we can get some volunteers to do the legwork.
 

3125b

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#12
Performance isn't too bad, however with 2Vrms output it seems kind of expensive.
But then again, there are worse choices for more money.
 
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#14
I just saw an article come out on this product and as I was wondering how this will do on ASR testing, come here and see it on the page. Good product launch on their side I guess. Did they have an embargo or release date for reviews?
 
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amirm

amirm

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Thread Starter #15
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amirm

amirm

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Thread Starter #16
I just saw an article come out on this product and as I was wondering how this will do on ASR testing, come here and see it on the page. Good product launch on their side I guess. Did they have an embargo or release date for reviews?
They did. I received the product about 3 weeks ago I think. Embargo was until 7:00am this morning. I believe I was the only technical reviewer to get a product to test this way.
 

TheTalbotHound

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#18
I quickly generated that chart last night and it is not an exhaustive list.
Would it be possible for you to make SINAD and power comparison charts like those you have made for dongle style devices but for battery powered (transportable) gear such as the iDSD micro black label or chord mojo. I think it is the only category missing direct comparisons on this site and such comparisons could be useful.
 

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