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 .
My original post is on CA and Pez draw my attention to AC, so now I cross post it here. Background:
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, 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 portLab (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.Sound
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.Sound
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
.(Updated 09 Feb 2017)3. iFi iPurifier2 (USB2.0, US$109)
This is iFi second generation iPurifiers, which belongs to a group of USB gadgets that all regenerate the USB in one way or the other, basically they all are glorified USB hubs. The aluminum chassis of the iPurifier2 has a very solid feel, it is quite a statement to have this kind of build quality at this price, also quite amazing is how did they able to pack an USB regeneration device in such a small footprint. It doesn’t use any external power so it is the easiest to use, just plug and forget. Lab
As it does not use any external power, it instead uses what iFi calls Active Noise Cancellation (ANC) on the power lines. We can see the improvement of at least 20dB noise reduction from the computer port alone, so the ANC works as advertised. However, as the overall power supply quality is depends on what you feed it in, this ultimately will vary system from system, but what we can see here is it does reduce overall power noise.Sound
The overall sound improvement for most of the DACs I connected after gave improved bass and dynamic and had a more nondigital, transparent, 3D and musicians were both more precise and more expressive. It is definitely in a different league when compare to the first-generation gadgets (Jitterbug/original iPurifier). I think the main reason is the iPurifier2 (and all other glorified USB hubs) improves upon the 1st generation is twofold:
1. Better quality USB data
2. Better quality USB powerConclusion
Overall, I will rate the iPurifier2 with a score of 70. So for the price, I think the price is justified by the significant improvement it brings and the build quality it has. If one wants an inexpensive USB gadget that actually works quite well and easy to use, recommended. 4. Uptone Regen (USB2.0, US$175)
The Regen comes in a small nice metal case, a generic SMPS power supply. There are 2 things puzzling me a bit: (1) for this price, Uptone really can throw in a nice power supply and not a generic SMPS one, (2) for this price, can they not glorify a USB3.0 one rather than the ancient USB2.0 one. Having say that, let the performance doing the talking, shall we?Lab
A very nice noise graph, actually I think the graph is now limited by our test gear (EMU 0404), as you can see later also for both iFi iUSB3.0 (nano and micro), they achieved very similar graph. So I would say the Regen does measure very well and provides a clean power supply. Sound
Actually, the sound signature is very similar to the iFi iPurifier2, improved bass, dynamic, blacker background and improved space; guitar drums had more realistic impact and sax solos were cleaner.
The Regen does give a darker background and a tag smoother than the iPurifier2, the difference is not huge.Conclusion
For the nice improvements brought by the Regen, I would give it 75 out of 100. I would say if without the rest of the USB gadgets in this group test, Regen will surely rule the party performance wise. Whether it justified nearly doubling the price of the iPurifier2? may be ... but just I would say, cost/performance index here is not as high as other members of this group test.
75 Uptone regen
70 iFi iPurifier2
50 iFi iPurifier (discontinued)
49 Audioquest Jitterbug