USB noise filter, jitterbug or ifi

Thanks for the interesting/varied responses.

Phil,
Can you describe the improvement you experienced. Simply lower noise floor, maybe emi/rfi related or maybe some sort improvement with clocking related jitter from packet delivered data .... idk.
Maybe a new thread, but has anyone noticed a difference in native dac memory versus the use of a memory stick as source of music files?

Erik, if you opened one of these little things up what do you think we would see?

Recluse,
Probably a variety of things.

Again, look at the Audio Science Reviews for these things. They have the best measurements on what is actually working and not.
Also, I used the Wyred4Sound Remedy and found it quite effective with older DACs, but it wasn’t USB. New DACs didn’t care.

Regardless, none of the anti-jitter products I am aware of are intended for use between a memory stick and a streamer. There's a lot more that the streamer has to do than read audio data. You want to have the jitter taken out afterwards.

In the old days, USB ground loop isolation was not common, and made a difference especially with laptop power supplies. Now I rather expect all decent DACs to have this.

And as ASR and the recent Stereophile review shows, those devices are nearly worthless with top tier modern DACs.

Thanks. I should have known. ASR covers it ;-)

recluse, jitter can be introduced with USB interface two ways - direct or indirect.  Direct happens when DAC uses average computer data rate as a source for D/A conversion rate (synchronous USB).  With asynchronous interface D/A clock and incoming data rate are independent and the problem of getting right amount of data is solved by signaling back to send more or less samples, but jitter can still be induced indirectly by injecting computer's electrical noise, that can affect D/A converter clock.  In either case computer initiates transfers and injects the noise.  Without computer DAC has to initiate transfers and there is no electrical noise to be injected.  I agree with Erik that such jitter reducing device should not make any difference with USB flash drive.

I'm using Wyred4Sound Recovery USB and find it highly effective. 

PS. The iFi noise filtering dongle has been proven to work as advertised by ASR, athough they were not able to measure effects at the DAC out.