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Generic Budget USB to AES Converter Review

Rate this USB to AES Converter

  • 1. Poor (headless panther)

    Votes: 98 83.8%
  • 1. Waste of money (piggy bank panther)

    Votes: 16 13.7%
  • 3. Fine (happy panther)

    Votes: 3 2.6%
  • 4. Great (golfing panther)

    Votes: 0 0.0%

  • Total voters
    117

amirm

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This is a review and detailed measurements of a generic USB to balanced AES digital converter sold on Aliexpress. It was kindly drop shipped by a member and costs US $17.02.
Aliexpress USB Digital Interface To AES Converter Adapter Cheap Review.jpg

The converter is everything you want it to be: simple with a robust aluminum case and even included USB cables! Member interest is in using such converters with professional studio monitors that only have AES input. Let's see if it can transfer digital bits from USB to AES including timing without spoilage.

Aliexpress USB to AES Converter Measurements
Let's start with purely digital test case. USB signal from Windows computer to digital AES input of the Audio Precision analyzer, and examining the jitter spectrum:
Aliexpress USB Digital Interface To AES Jitter J-Test Measurement.png

The lines in green (barely visible) are the spectrum of jitter when I am using Audio Precision's own AES output, going to its input using a 6 foot XLR cable. Red replaces the source with the USB to AES converter. As you see, we take a massive hit to the tune of 50 dB. Clearly there is some kind of clocking issue here.

Serial interface on DACs has some amount of filtering (of high frequency) jitter. Let's see if they can handle this amount of degradation. I powered on my D70s which is on my desk, first using Audio Precision as the AES input:

Topping D70s AES Input Audio Measurement.png


We see the squeaky clean response of the DAC as we expect. Now let's feed its AES input through the generic USB to AES converter:
Aliexpress USB Digital Interface To AES driving Topping D70s DAC balanced Measurement.png


Wow, that is some serious damage! FYI I switched to 48 kHz and problem remained.

Conclusions
It is clear that these converters have a serious design problem when it comes to conveying the digital signal and its timing. They may be using simple USB adaptive interface and with it, carry all the computer USB jitter. Or some other problem. It is a serious shame as the cost is more than reasonable. Seeing how the analog output of the DAC is disturbed by large factor, it is hard to justify using it. Note that some AES receivers may even fail to lock into a signal this bad.

So yeah, "bits are not always bits." See my video on this (around 9 minute mark):
I can't recommend the Aliexpress generic USB to AES Converter. Hopefully we can find a bargain one that works well in the future.

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

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 
Even if we found such a converter at a small price which did measure well, the state of the market is such that we wouldn't necessarily know if we were actually being provided with the good one when we order. AliExpress and Amazon have so many identical-appearing products under different, obscure (and often silly) brand names that I simply don't trust any of them. So the value of this review, it seems to me, is more about not ordering generic, cheap stuff under any circumstance unless and until there's more transparency about the actual manufacturer and its track record.
 
Maybe these measure better?

xingcore af200
quloos qu02 (has some on their site)
matrix-x spdif 3

 

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matrix-x spdif 3
Matrix is a proper engineering company so if I were to guess, I would say yes. I don't know about the other two.
 
It looks it transfers 16 bits only. From both J-test and THD plots it is evident.
Driverless on Windows it can only do 16 bit according to the description, or at least there seems to be one driverless mode that does this…@amirm, did you install the driver?
 
Driverless on Windows it can only do 16 bit according to the description, or at least there seems to be one driverless mode that does this…@amirm, did you install the driver?
This is the spec:

"2: 16-24bit/44.1K-96KHz (no drive)"

Which is what I tested (24 bits at 44.1 and 48 KHz).

The driver it claims is needed for 192 kHz (or 32 bit) which I suspect is wrong. USB class driver was updated years ago and no driver is needed anymore.

That said, it could be truncating in addition to other things it is doing wrong.
 
Thanks for the review. This is exactly the reason I cant buy a cheap USB-> optical converter without it being measured first. We spend all that money on our gear and then cheap out on one part of the chain.
 
I've got a similar looking AliExpress device that does SPDIF to AES (active, not passive, required due to long cable runs). I'm hoping it's not this bad, due to the much simpler conversion involved !
 
So, all the noise resulting from inserting this gizmo into the digital audio chain is below -120 dB according to your plot.

Amir, are you claiming that this will be audible through speakers?
 
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