Got the JB, tried it on my laptop, PC and smartphone and did not hear ANY difference in ANY configuration.
Hardware/configurations I used:
- Always with Dragonfly Black
- A pair of Grado SR60i's
- A pair of AKG K181DJ UE
- W10 Foobar 2K on laptop with relatively good sound hardware and a generic, old PC with crappy motherboard
- Android Foobar 2K
- A variety of music from all genres and lossy/lossless sources etc.
so: Device > JB > Dragonfly > Headphones
I did also try the JB in a separate USB port on my laptop/PC but this also did not affect the sound audibly. The difference between the standard analog outputs of my devices and the Dragonfly Black was always very clear in any configuration. So my ears have that going for them.
I'm happy most people here seem to be getting some benefit of the JB, but it smells so much like a scam to me. The digital noise they speak of at Audioquest, I can't think of a way for it to exist. If bits would be arriving in the wrong order or with the wrong timing over the USB, at frequencies that would cause any audible artifacts when converting to analog, you would have continuous errors when transferring files or when doing anything else via USB. I believe the sole reason USB can exist and be successful is because those kind of errors are extremely rare; they certainly don't happen at frequencies that would cause large portions of the spectrum to change characteristics. To cause audible artifacts in the range people are reporting most here (bass, mid..), say between 20-400 Hz or so, then there would need to be misplaced or misinterpreted bits reaching the Dragonfly at those frequencies at the bare minimum if we assume bitstream coded audio (I actually don't know if that's the case). That seems like a whole lot to me and not in line with the USB specifications at all. Also, single bit errors contain by definition a lot of high-frequency components since they are white noise (again assuming bitstream audio) but nobody is reporting on increased clarity at the highest treble range. If the audio is still somehow encoded before reaching the Dragonfly (not bitstream) then single bit errors should cause artifacts that are much larger than those of single bits in bitstream audio. Again, this isn't happening so if the Dragonfly does not receive audio as a bitstream but as packets that are still somehow compressed, the bull****-meter for the JB would truly go through the roof.
I really feel this is a similar case to those $10.000 HDMI cables that 'improve' the audio and visual quality of movies etc. There's people who swear by those as well and claim they can hear/see the difference..
I don't notice ANY difference and Audioquest's explanation for how the Jitterbug should work seems pretty nonsensical to me so unless any of you can come up with an ACTUAL explanation as to how it might work I think it's safe to say it's a scam or all my equipment is somehow the greatest.
