Group Test: USB gadgets (AQ Jitterbug, Uptone Regen, iFi iUSB3.0, iPurifier, iPurifier2, UPDATE on p.15…)

[Liam]

Thanks indeed for your interesting tests.

 

I use iFi Gemini USB cables (twin legs) with the iPurifier 2's in my two systems. The DC power legs of the cables are not connected at all to the computers (Mac Mini and iPad), and are separately fed with DC from small 5v DC linear PSU's (Aqvox), which I happened to have. The DC from the Aqvox's is in turn fed through iFi DC iPurifiers to power the iPurifier 2's. A belt and braces approach in an effort to supply clean power to the iPurifiers and avoiding the normal USB power. In the case of the iPad it has the additional benefit of conserving it's battery.

[Liam]

@robocop

"New Dac's should cater for the USB input discrepancies and engineer to over come them onboard, not another box with more connections/cables!!!!"

AMR and iFi do pay particular attention to those matters in dac design, and deal with the shortcomings of spdif as well. The AMR DP-777 and the iFi Retro for example, and likely other dacs in the iFi range. Between those and the various gadgets/cables they pretty well have everybody's back covered.

[Liam]

Not sure how you come to this conclusion: on the one hand "the DACs design already deal with these" and on the other hand, there are additional accessories to clean up the USB. This is contradictory.

 

In my iFi iDSD Nano, there is a definite improvement in SQ when I cut off the computer power and have only Data coming from the Computer. I get further SQ enhancements with a filter at the computer-side as well as injecting clean power DAC-side, with either a Linear Power Supply or a battery charger/pack giving better results than an SMPS IMO and even further SQ with additional modifications on the connection and PSU.

 

I agree with @robocop that ideally, these technologies should either be included in the DAC, but of course, at a certain price point, which is to be expected, or else what I believe is that the whole of the USB connection as well as how the DAC allwos power in should be revised.

 

In mentioning AMR I was obviously meaning the DP-777 dac and I meant to mention by name the iFi Retro 50, which has trickle down technology from the DP-777. The only accessories I have added to these are iPurifier2's and (my choice...I feed these with LPS, which are filtered with DC iPurifiers via iFi Gemini cables as mentioned earlier.

 

I have not kept close watch on the other iFi dacs, but as iFi go along they tend to upgrade the newer gear. As you say price has a bearing of course, but at least the options are there to upgrade performance with add on's as desired and budget allows.

 

For those desiring spdif connection both of the above dacs include optimising tech on board as well.