Six DAC Comparison

@fuzzbutt17

I do not think anyone claims I2S is the be all, above all interface for audio, in fact, USB wasn’t to be either. It just so happens that in some DACs they simply sounds better for whatever reasons.

Most off-the shelf DAC chips will have an I2S interface to talk to and hence some manufacturers thought it would be wise to make it available externally, even though I2S is only meant for short connection, typically few centimeters. Now we see more and more DACs coming up with this interface - maybe they just want to have it for convenience and be competitive or maybe the designer have really put some effort to do it correctly (and there are good examples of it).

Another thing that is a FACT is that I2S is not approved by the Audio Engineering Society (AES) as an external data transfer protocol.

That alone should make any rational person question what these companies are doing and why they are doing it. 

Have you considered that those companies who are promoting I2S are putting less $$$ into their other inputs so that their I2S input sounds relatively better?

I have not seen any manufacturer claim or promote their I2S input sounds better. All I can tell is I had two DACs with I2S input and in both DACs, there was no compromise on the USB implementation from the manufacturer side and I do not typically use AES/SPDIF as my DIY server doesn’t have it.

To have I2S or not is a choice for the designer/manufacturer and the market they want to serve. I still believe a well implemented USB both in the DAC and Transport (along with an optimized s/w) would be sufficient in most cases, however we cannot really generalize it and at the same time nobody is bashing Mojo DACs for not having I2S either :-)

@fuzzbutt17  Thanks again for all the good info, and it makes sense.  Could you clear up if using a DDC and SPDIF, AES, or i2S connection to a DAC if both the clocks in the DDC and DAC are in play?  The clock in my DDC is better than the one in my DAC, and my hope was the clock in the DDC by sending a better signal to the DAC it would have less “work” to do and help it sound better.  Am I off base in that reasoning and are both clocks in play?  The sound is notably better with the DDC BTW.  Thank you for any thoughts. 

Usb wasn't developed as an interface between streamers and dacs, this interface has no inherent advantage over I2S. I2S interface not universally used due to the fact I2S clock best placed closest to data lines. So, we can then all agree I2S clock in an external device not ideal. Now not being ideal doesn't necessarily mean it can't or won't be superior to usb or some other interface for any specific dac. My Musetec dac has a highly developed custom build usb board, far superior to what I see in vast majority of dacs, Laiv has far more pedestrian implementation, this approximates what I see in most. My specific streaming setup and implementation of both I2S AND USB interfaces provides me with superior results via I2S. I posit quality of any input interface INTO DDC is critical, output is only part of the equation. In direct comparisons of my optimized usb vs optimized I2S, I2S wins out. And I will continue to state YMMV, this just as others should admit.

@ Soix

Clocking is just one of the many factors.

Re-clocking doesn’t fix corrupted data. 

And as I stated, it is not the accuracy of the clock that matters, but rather how little clocking noise it produces that pollutes sensitive analog components in the audible spectrum. 

So you can have the ultimate low-noise clocking in any number of components in your digital signal chain and then have your digital data corrupted or your analog signal polluted because of the clocking inside of your DAC.

Every link in the chain matters.

Think of the analogy of taking a photocopy of a photocopy of a photocopy of a photocopy.

How much of a difference would it make if you used all high res scanners and printers in the chain but one was low res?

All you would end up with is a very accurate reproduction of the worst scanner and printer in the chain. 

Or what would happen if you had all high res scanners and printers in your chain but then your last scanner and printer was low res?

@ SNS

Your DAC can have a very advanced USB input.

But if the output from your digital source and your digital cables are not equal then you cannot make a fair comparison between USB and I2S. 

All the inputs and outputs on any component are not equal. 

Companies who are promoting I2S are making sure that their I2S inputs and outputs sound better than the other inputs or outputs.

USB may not have been created for music but it was created for component-to-component data transfer. 

I2S was not created for component-to-component data transfer.

Can anyone name a pro audio component that is used in professional recording studios that uses an I2S input?

On the other hand, USB is used in professional recording studios.

What does that tell you?