Is usb reclocking necessary?

@mijostyn says:

No. Only unclocked USB signals need to be clocked. With modern clocks reclocking is unnecessary.

Well, that appears true on the surface. And most people don't specify enough configuration data to rally know. But let me be very clear: with systems running with the source as slave and the DAC as master (clocking), and with stuff that was considered well-clocked when it was new, adding a USB interface with isolation and re clocking has made a huge difference several times.

Note that my data point is NOT a box in the middle, which brings its own can of worms, but a replacement of the coaxial SPDIF provided originally with a custom PCB with independently powered (line powered) USB; full ground, signal and power isolation; clean power to the processing stage, and tight clocking beginning with a read buffer --> then spit out to the DAC.  Yes I'm being a little vague.

So while your point is well taken it comes down to "how well is the internal clocking/timing implemented?", "how dependent is it on source timing?" and "how good is the magic box being added".

I tend to agree that i would NOT just add a magic box.

@yage Thanks.  In that case I cannot see any reason even for filtering.  

Hi guys, old thread but hoping I could revive it to get some help. Is a USB re-clocker going into a DAC with a asynchronous USB redundant? From what I've read in an asynchronous setup, the DAC will re-clock when it pulls the info from the server/streamer. So it would be re-clocking out of the streamer/usb re-clocker right into another re-clocker? Looking at getting a DAC that has an asynchronous USB and  and Innuos streamer. Would I really need the Innuos with a re-clocker if my DAC has asynchronous USB or could I potentially save some money and just get an Innuos mini streamer?

@bg3584

While you are correct that the streamer is slaved to the Dac under asynchronous USB, the actual connection needs reclocking since USB as a two way port has a separate algorithm rather than embedding the clock signal in the data stream. Hence the utility of the reclocker.

I used a pretty good one (Mutec MC-3+USB) into a $6k DAC-Preamp on the Stereophile "A" list. There was a positive difference. Then, I got a newer DAC-preamp ($4k), and I found that the reclocker added harshness to the sound.

My conclusion: this is just as system-specific as power conditioners and maybe even cables. Try to be objective when you evaluate a reclocker in your own system, and don’t buy anything that can’t be returned for full credit. And finally, don’t listen to technical arguments for and against, as many of them are just BS. Listen to the sound with your own ears, in your own system, and if at all possible, make blind comparisons.