Digital Audio Output Differences? Is USB Audio Really The Top-notch?

"Legacy" outputs on a server / player are common. For example, Grimm Audio's MU1 is optimized around AES/EBU (and Coax). The Antipodes K50 is around it's AES/EBU as well (including others). 

The receiving component's "optimized" input is critical as well. In other words, you'll get the best results if both components are optimized around the same I/O.

I use ethernet & optical links when I can, not USB. And yes, my superior ears (or is it my sheer gullibility?) tell me I indeed get better fidelity.

Not sure what streamers you're looking at but there are plenty with AES3 out. 

As @david_ten  mentioned, having multiple port output options gives you versatility in choosing a DAC.

USB is used in some better DAC designs that run in asynchronous mode.  Among other advantages, these DACs apply their own internal clock, thus eliminating jitter. 

However, other port types besides USB  have more recently been configured to run in asynchronous mode, including S/PDIF and AES/EBU.

  Also other excellent DACs exist that use completely different approaches and are not reliant upon USB ports. PS Audio, for example, with I2S, etc.

Do you have a DAC?

Since most dacs optimized for usb these days, likely best output for streamer. However, one could have that rare dac in which usb not optimized in which case I2S could be preferred. The problem with I2S is no pin and/or connector standardization.

+1 to @sandstone 's post:

USB is used in some better DAC designs that run in asynchronous mode.  Among other advantages, these DACs apply their own internal clock, thus eliminating jitter. 

However, other port types besides USB  have more recently been configured to run in asynchronous mode, including S/PDIF and AES/EBU.

  Also other excellent DACs exist that use completely different approaches and are not reliant upon USB ports. PS Audio, for example, with I2S, etc.

What is your DAC? First things first, you can only use the outputs in your streamer that your DAC supports as inputs.

And as you already have bought the streamer, you can easily try all the outputs for yourself, with your DAC, in your home. Yes, you will have to spend some of your time with experimenting, and buy some cables, but it's part of the fun. There is really nothing to prevent you from trying for yourself.

As @sns points out, generally speaking "most dacs optimized for usb these days" is true. I would dig deeper into your Silent Angel "streamer" to see if there is a clear preference in output by the manufacturer / owners / reviewers.

Personally, I would prefer to see a singular approach to maximize BOM for a dedicated / optimized output...however, this is very limiting for the manufacturer as it ’niches’ their product.

Grimm Audio, is an excellent example of this. They have done a fantastic job with AES out, but had to add Coax to suit more users.

I’ve spent the last few weeks considering mid to upper tier servers/players and eventually narrowed my options to those that are singularly focused on USB out since my DAC is, per the manufacturer, optimized for USB.

And if the USB Audio can provide the " best " digital sound quality, then why added other ports? Ain’t that just costing more on the manufacturing end?

BTW, I was careful in my use of "the receiving component" in my initial post, so as not to exclude DDC components (vs. simply stating >>> to the DAC).

If, for some reason your DAC and streamer are not optimized around the same Input/Output then a DDC is a solution should you want to maximize performance.

Other companies do this, but since I am familiar with Denafrips, I’ll use them as an example. Their DACs, per owner feedback, etc. perform very well using the I2S input...which makes a strong point for using Denafrips’ DDCs so that one can use the DDC’s I2S output to max effect and benefit.

Finally, there are advantages to using the same manufacturer's server/player/streamer, (DDC if available), and DAC as they are already optimized to work together.

FYI, the Pro focused manufacturers tend to optimize around AES.

You are asking a seemingly simple question in a complex field.

yes, USB >> SPDIF (or its kissin' cousin, AES) - but only if its is implemented correctly.  Or if the SPDIF is crummy (usually true) or....

So while i would begin with USB, you now need to make sure you have clean power, clean (isolated) ground and a DAC with a good clock since it is not the only thing with a meaningful impact on jitter.  Most modern high end DAC do pay attention to both.  How good they are of course varies.

If cables sounds different, there are serious problems.  Some really are that bad, but its usually something else.  Note that almost every "coax" SPDIF cable on the planet has an improper termination - RCA plug are almost never 75 ohm characteristic impedance.....and it just gets better :-)

I have a RME adi2 DAC , it’s a great sounding DAC to be sure....   I use all three inputs and honestly I can’t tell the difference between my coax and the USB.  It sounds so good from all three , it’s like splitting hairs.   

I2s is the best connection in my limited digital experience but finding equipment from different manufacturers that will have the same I2s configuration is a challenge. I don't stream but tried connecting the ps audio pwt to a gustard x26 pro to play my CDs with zero success. Now I switched to the Jay's cdt2 mk3 and the I2s connection to the gustard is fully operational. The sound is frankly so close to my analog rig now, it's hard to tell the difference. And I have twice the dollar amount invested in my analog rig vs. the digital one. I am completely sold on I2s when feasible. And I also want to take this opportunity to thank the digital audiogon community who steered me in the path of my digital journey. Without it I would still be mainly analog. And CDs are so much less expensive. Today I ordered $120 of CDs on discogs including shipping and I am getting over 10 CDs for it, about a third of what vinyl would have cost me and some titles don't even come on vinyl. This is a huge step forward for me. Sorry for getting off track here but just got through an unreal quality CD listening session tonight and felt like sharing.

USB is the worst connection you can use, even if you buy into all the gimmicks/tweaks you can buy to try to make it better.

Ethernet and i2s are much better, but only your better dacs include them and they are usually more expensive 

It really does depend on the implementation, but I have never had good results with USB. I have tried USB directly from my PC, from an audiophile server (an Antipodes), and from a number of streamers - Lumin U1 mini, SOTM, Ultrarendu and OpticalRendu, and currently my Bricasti M5. I have used good USB cables - Furutech and Shunyata. I have also tried a number of very good dacs - Chord DAVE/M Scaler, Mytek Manhattan II and currently my Nagra HD Dac, all of which have very good USB implementation.

I always find USB sounds hard, "digital" and unsatisfying. To my ears, SPDIF and AES sound more natural and tonally more complex. I currently use AES from my Bricasti M5 to the Nagra dac. However, a well-implemented ethernet input can also sound extremely good, and was the best input on the Mytyek Manhattan II.

The only way you will know is by listening to them all. But despite its theoretical advantages, USB always seems like a poor choice for audio in practice.

I have a PS Audio Direct Stream DAC.  I've used USB, Ethernet, and i2s with it.  i2s is by far the better option.

If you want to use USB get a DAC or DDC with an Amenero board. This will bring the SQ equal or better to AES/EBU.

It is such a close call using my Musetec 005 DAC with my Aurender N20 I cannot say which one is best only that they are different. Should get my new USB cable today so I guess USB will be better, I'll report back.

Before I got the Musetec DAC, USB was in no way comparable to AES/EBU.

I use digital coax from my Node2 streamer and Toslink from my Audiolab cd transport to my MHDT Orchid DAC. I did a lot of research and asked a lot of questions to both my MHDT dealer and Silnote Audio (interconnnects) and came to the conclusion that as long as the DAC supports the same bit rate quality on each of the port types it should only come down to the quality of your cable. I made sure to get Wire World’s highest grade Supernova 7 Toslink cable (Silnote chose not to produce a Toslink line) since Toslink made me the most nervous for various reasons (neither the streamer or the cd transport support USB), including the bending of the fiber optic cable (I prefer the shortest cable length they offer in this application) with the highest quality glass (not plastic), etc. Toslink will pop out of the port much easier than the other connectors, but one just has to be extra careful not to bump it and make sure it is seated properly each time I’m moving components around a bit. Done right, I think I would be happy with any of the connection options.

One feature that distinguishes the better USB implementations in a DAC is that the 5V power is supplied internally by the DAC and not by the power line in the USB cable. Among other things it makes the selection of a USB cable easier, and allows it to perform better, since there can be no 5V interference with the digital lines.

I have never liked the usb connection, nor coax. I prefer aes and have gravitated to dual aes - yet a further improvement. And different cables provide different quality of course.

My first few DACs clearly had a worse implementation of USB than the other inputs.  It wasn’t until my current DAC, which I’ve had for about 4 years now, that I felt all inputs, including usb, were equivalent.

   The OP seems to assume that usb is universally regarded as the best sounding input.  Besides my personal experience, simply being a member here and reading the comments through the years has led me to believe otherwise.

  Usb is the most ubiquitous output.  Every computer has one as do multiple consumer electronics that one may wish to plug into a DAC.  Therefore DAC manufacturers have to add the add the input.  The need for reclocking makes it more difficult to work with, but they have been at it for a few decades now.  Some manufacturers may actually prefer to work with usb.  More power to them

USB is a new comer… when PCs joined in the audio arena. Typically DACs had no USB input. At first DACs did not support them… it is packeted info… not just a digital bit stream.

So, audio equipment popped up that only supported USB, then the USB input was added to higher quality equipment. Which is better is completely dependent on your DAC / source combination. Sometimes it seems that which ever is the higher quality DAC or source), but that doesn’t always work. I have a top quality streamer and DAC and it is really hard to tell the difference. I give the nod to AES.

Trying to understand why I hear a difference between USB vs  spdif and AES inputs.   I compared a vintage tube dac with a current solid state dac.   I have a Levinson 31.5 reference transport.   I connect it to a Sonic Frontiers MkII DAC via optical SPDIF or a Schitt Modius dac via AES.... I can't say there is much of a difference between the two dacs and the differences are subtle.   Relevant to this thread...   I never developed a preference between comparing the optical and coax connections on the SF and had no preference comparing the Coax and AES inputs on the Schitt Dac.   

What surprised me was the difference between streaming a flac file of a cd to the USB input of the Schitt versus the cd played on the transport via AES to the DAC.  I can't say one is better then the other... they are just different.      The transport to the Schitt (or SFdac)  is a bit more velvety sound quality while the USB is a bit more crystalline.   Why such a difference?....

I can imagine a parade of reasons...and none make a lot of sense to me since I can't say the USB sound is good or bad....   just different...and I have no basis to understand the differences.     So.... explanations  like  Jitter from the transport to Dac.   Noise from the PC polluting the USB DAC or jitter in the USB interface etc etc  are all theoretical to me and make no sense.   Thoughts would be appreciated!

.

USB is fundamentally a different communication method from SP/DIF and AES. USB needs packet conversion, retiming to a bit stream… so that is a function that now falls on the DAC. SP/DIF are the same through different connection types. Optical is usually not as good as it has to go through a electrical to optical conversion, and then back.

...mmm....What always and still pesters me is the apparent disinterest in optical ICs'...

It would seem anything that can carry a SOTA video stream would be SOP for audio....

....or did that ship 'sail', left in reverse, and take out the dock? ;)

Curious, if anyone feels like comment....

All eyes (ears occupied), J

@asvjerry Hi, as Mr. Prentice mentioned above, conversion must take place with Toslink and it's bandwidth is limited to 24/96 Khz. Wadia tried to introduce I believe AT&T Glassfiber, which apparently was good, back in the day..

Weiss have a very sophisticated glassfiber long distance cable but it's quite expensive.

AES/EBU and COAX generally have to use DOP for DSD but USB goes through no conversion for DSD, nether does I2s.

Toslink has taken out the dock and I'd hazard a guess that it's slot will be replaced by I2s.

@lordmelton , thanks for that 'illumination' on fiber.  It seemed a 'natural' for audio, but it's limitations were unclear to me.

I've got a couple of 1 meter cables in place, but rarely called upon for the 'day to day' listening....

Appreciably yours, J 

AES sounds more real and incisive than USB to me; and I’m using high end USB cables and Innuos Phoenix re-clocker between a Bryston BDP 3 player and Holo Audio KTE May DAC.

I had a Music Server with I2S and USB out,  the USB was better.

USB has gremlins and is hard ($$$) to get right.  My current Innuos Music server has  renowned USB re-clocking but I use a DDC to convert to I2S as it is the preferred input on my Terminator DAC.

It can be hard to compare as the USB cable and I2S cables are different and have a profound influence on what you hear.

There is no one-size-fits all. It depends on the DAC, the streamer, and most importantly, your sound preferences.

From my personal experience of ownership, at least two examples when the USB input of a DAC sound better to my ears than built in Ethernet bridge: 1) Ayre QX-5 Twenty, and 2) MSB Discrete ProISL USB module