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What is Asynchronous USB? | Do You NEED It?

by Stuart Charles Black

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What the heck is “Asynchronous USB?”

Is this yet another audio scam designed to trick people into buying sh** they don’t need?

All of these answers and more, comin’ up!!

Greetings bass head, Stuart Charles here, HomeStudioBasics.com helping YOU make sound decisions leading to a beautiful audio experience that will make you fall in love with music, all over again, so…

Asynchronous USB is found in DACS that utilize their own internal master clock to pull data from your PC (in accordance with the DAC’S own timing) in the digital form of 1s and 0s.

That data is then converted to analog and sent to your ears distortion-free, theoretically.

This clock drives the converter directly, and does not rely on, nor is it synchronized with any of the PC’s internal clocks.

Further to this, are the benefits of using asynchronous USB audio. A computer and a USB DAC both have their own internal clock which dictates the timing for both devices. One of the problems with USB audio transfer is that these clocks are not running at the same time. Digital music is sent as USB packets from the computer down the USB cable to the DAC. These are sent in periodic time frames according to the computer’s clock.Cambridge Audio

The timing errors essentially cause what’s known as Jitter, leading to distortion of the audio.

Synchronous vs. Asynchronous vs. Adaptive

In synchronous USB mode, the USB host (typically your computer) provides the clock signal that controls the data transfer.

The device (e.g., audio interface or DAC) must synchronize its clock to match the host’s clock signal.

This can introduce jitter, which is the variation in timing of the data packets, potentially degrading audio quality.

Not ideal.

In an Adaptive USB DAC, the internal clock of the DAC is adjusted every millisecond to match the flow of data.

Not exactly ideal either, and can also result in Jitter even though it’s technically better than a Synchronous transfer.

In asynchronous USB mode, the device controls the timing and clocking of data transfer independently of the host.

The device generates its own clock signal, ensuring precise synchronization and minimal jitter.

Put another way, the data is requested by the DAC in harmony with its own internal clock, thus reducing Jitter as much as possible and providing you the listener with the best experience, distortion-free.

This results in potentially higher audio quality, especially for applications like high-resolution audio playback.

Do I personally believe Asynchronous is better?

I can’t really say one way or the other, but I’m leaning toward yes.


Yeah, that’s right you heard me correctly!

Most of my regular readers and followers by now know my zero-tolerance policy for snake oil in this hobby.

Asynchronous USB is something I’m still not quite sold on one way or another, but my brain may perceive a slight difference.

When I demoed the CEntrance DACport HD back in February of 2020, it did stand out a tad more in terms of the “clean sound” or whatever, but I really can’t be sure if it being Asynchronous was the kicker because I don’t know exactly which DACS utilize Synchronously and which don’t.

That’s a whole separate can of demo worms for another day.

I will say that the DragonFly Red is one such Asynchronous DAC, and I do tend to recommend it a lot more often than some of the others I’ve had experience with.

CEntrance DACport HD Review

What’s for breakfast? “Yeah, I need my knife if we’re going to eat. Thanks. Yeah, it’s right over there. If you could just hand it to me that would be great. Yeah, I mean I could use my hand too. No big deal.”

The DACport is also an Asynchronous USB DAC, and it did seem smoother and more fluid sounding as well.

But that could have completely been my imagination.

There are dozens of DACs I’ve demoed that all sound fantastic, fluid, etc.

The real question is this:

Will you actually be able to discern Jitter going on in real time?

I have never once complained about the way a DAC delivers music to my ears.

As it stands now, I honestly don’t think most people would even be able to tell.

I’ve demoed the DragonFly Red against countless DACS. It does tend to sound more open, crisp, and grand.

The portrayal of Soundstage with it is definitely better than many of the others.

The Chord Mojo is another example and still is the best DAC I’ve personally heard, right alongside the Bryston BHA-1 (Not Asynchronous AFAIK, but I can’t find a definitive answer).

I’ve talked about these 2 countless times in articles and videos.

In this case of the DragonFlies, DACport, and Mojo

Can we boil down their superior performance to a lack of jitter?

I don’t know the answer to that question definitively. I’m just giving you some food for thought.

It may very well be the determining factor, and why I’m always recommending both the Mojo and DF Red to people from a purely sound standpoint.

They both perform really, really well.

The NAIM DAC-V1 is another example of a product that stands out to me.

It’s incredibly neutral and crisp sounding if a bit too sterile at times.

Still, it’s one of the best performers that I’ve personally tried, and it’s also an Asynchronous DAC.

Perhaps there’s something to it.

In any event,

I think the way a DAC sounds mostly comes down to its DAC chip, but more importantly the output impedance.

People will argue with you all day on this sort of stuff, but I’m a firm believer that the way the track itself sounds has way more to do with how it was recorded, mixed, and mastered rather than all the other extra fluff that ends up causing audiophiles to go into a rage.

These are basic principles of sound engineering and will never change, no matter what some Reddit snob with too much time on his hands says.

Three Asynchronous USB DACS.

Video Discussion

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Final Word

Asynchronous may very well be the way to go when shopping for DACS, but it’s hard to say one way or another.

I will update this article as new information comes to light.

I have demoed over 60+ Amps & DACS at the time of this post, and it will be interesting to find out which of those (outside of the ones mentioned above), utilize Asynchronously and which do not.

For now, check out the Cobalt shootout:


Well, that’s about it for today my friend! What is Asynchronous USB? I hope I’ve answered your question!

If you love what I do here and want to support the blog and channel in a more personal way, check me out on Patreon and discover all the value I have to offer you.

Questions? Comments? Requests? Did I miss the mark on something? Please let me know down below or Contact me!!

Is it worth it to pursue a DAC that utilizes Asynchronous transfer of data? I would love to hear YOUR thoughts. Until next time…

All the best and God bless,





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Amir February 16, 2024 - 9:58 am

Heya, Mr. Stuart!!! Although I agree that basically async DACs and sync DACs (which the K5 Pro you love so much which also I do, thanks to your review) perform similarly, there is a reason why the Dragonfly Red markets itself to improve any system’s audio capabilities: it’s inherently independent and does not rely on the operating system’s own internal clock!

That means, should you run an old Windows 10 PC like mine with many work applications, the timing (or we can say something like a system interrupt) will sometimes go so high that dropouts, pops and cracks can be heard. By incorporating its own clock and timing circuitry, the DragonFly Red can bypass the timing inconsistencies of the host device. This feature allows it to deliver more consistent and high-quality audio performance across different operating systems and hardware configurations.

Kudos on an another great article!! Carry on and you rock!

Stuart Charles Black February 17, 2024 - 11:47 am


Thanks man!! It’s much appreciated. Reach out anytime 🙂



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