Can the digital "signal" be over-laundered, unlike money?

I don't want to misinterpret you or misquote you, so could you please write this more clearly before i reply? For example, are you saying that timing/jitter does not matter on the USB interface? If so, you are confusing a purely data signal with the quasi-analog signal that is fed to a DAC.So, please clarify the whole thing. Thanks.

Timing/jitter on the USB interface does not matter. This does not have any impact on the DAC analog output which uses a completely separate clock. That does not need to be a very expensive clock for very good audio performance. Sure, lots of expensive equipment makers say it does, but they can't ever support that claim. Chip based DACs, new ones at least, not 30 year old ones, are more immune to clock jitter as well.

Saying "quasi-analog" is marketing speak. It has no meaning. Clock jitter has meaning, namely clock jitter at the input to the DAC.

Electrical noise on the USB I/F due to ground loops is an issue, hence why I addressed isolation.

Please don't come back with pseudo-technical marketing fluff. That is not going to cut it except with people who have also drunk the Koolaid.

Competently designed DACs with asynchronous USB will buffer the input and use their own clock so no matter how many of these devices precede the DAC they won't affect the analog out.

@djones51,

Clueless but convinced to be right! Your definition of competently designed unfortunately seems to exist nowhere in the real world.

Really? No company makes DACs that can properly deal with USB input?  I think the one clueless about digital is you 

Two problems with that argument.  bear in mind i design these things both in T&M and audio.  The first problems i "not all DACs do a perfect re-clocking, and many, so as not to over/under run buffers begin with the input timing and then reduce timing variations".  The second is, like many thigns in audio, listening tests tell me that some issues remain after competent isolation and re-clocking.

Now, i have posted several times that when i have built my own USB interface (isolation, power, FIFO, etc.) and applied them to legacy DACs, the dependence on a good input signal is far less.  But its not zero.  You can deduce what you wish - i don't have all the answers, but at least i listen, and then ask questions.

Do i think the Ethernet switches make a difference? No i don't. Its isolated anyway and are queued anyhow. (I supposed que handling might matter, i assume that is mapped by the router, maybe not).  but clearly adding a bridge between server and endpoint helps, and a great USB interface helps, and providing a good input signal helps.

I do agree that most of the benefit comes from competent design of the USB interface. I also know that most designs are "data sheet engineered" and not ideal.

But be careful of blanket statements.  Not only can they mislead given real world equipment, but they turn off people who have heard "its perfect" too many times before, only to find out otherwise (and have the industry fix issues, you know those silly guys at AD and Burr-Brown).

Thanks for clarifying. I assumed we were not 100% in agreement, though probably more yes than no.

G