Group Test: USB gadgets (AQ Jitterbug, Uptone Regen, iFi iUSB3.0, iPurifier, iPurifier2, Intona, w4s Recovery any more …)
Disclaimer: For people who knew me, they all knew that I can be a bit critical, if you don’t like what you are reading, please simply ignore my reviews and enjoy the music.
The title may be a little misleading, a few years ago, these groups of USB gears are surely classified as gadgets, but nowadays, I would say they are indispensable in a computer audio system, mainly because:
1. USB audio device is one of the primary music sources now; and
2. USB connection is horrible for transmission audio,
so something has to be done.
A couple years ago, I did a small group test of the USB DACs, link here.
With those I started racking up different USB gadgets over time (man needs new toys). Again, I tested those with my Macbook, Shure 535 and Sennheiser HD 800, also with a pair of QMS active speakers. I also included some noise measurements result I took with a friend at his office lab (with a EMU0404).
1. Computer USB port
Lab (Power Noise Measurement)
This is a measurement taken on the computer USB port with loading. In an idea world, the noise line should be around -140dB (~a few uV, the green line), but in reality, the computer USB port is a lot worst. In fact, the computer USB port is ~1000 times (60dB) worse than the ideal.
When directly connected to the computer, all the DACs had the hallmark of the “digital sound”, dry, edgy, flat, boring and basically horrible.
2. Audioquest Jitterbug ($49) and iFi iPurifier ($99, discontinued)
The discontinued original iFi iPurifier probably was the first of its kind filtering both the USB Data and Power, later came the Jitterbug which did a Chinese copy (minus the Aluminum case) at half the price. As those two are so similar I lump those two reviews in one.
Lab (Power Noise Measurement)
Both of the iPurifier and Jitterbug’s graphs were so close, they basically overlap with each other, so I only posted one graph. they have almost no measurable effect on power supply noise in the range below 96kHz, above that they did reduce the noise spikes a little.
Put is simply, they work, but the overall effect is subtle (but any improvement on USB audio is nice). The sound is slightly more coherent and has a bit more depth, jazz vocal is reproduced with a bit more clarity. I found that the iFi iPurifier might have a slightly darker background than the Jitterbug, but it’s very close call.
Adding one more jitter bug into the system (one on the used port, one on the unused port), improve things a little but really not worth the extra effort.
Overall, I will rate the Audioquest Jitterbug a score of 49 and the iFi iPurifier 50 out of 100, so so for the money and don’t expect miracle, they both had their days but it’s time to move on. I would not recommend getting any of them nowadays.
50 iFi iPurifier (discontinued)
49 Audioquest Jitterbug
To Be Continued...