@haonan
i have some interferences when using my iems on the panam, which can be solved by touching the metal chassis. ground loop static?
I won't suggest you to get the Hifimediy China one, maybe if you are really budget-scrapped you can buy one to try out first, see how it improves yr current situation bcos IIRC yr PanAm is also USB-powered atm? From my japanese mags and what I had came across last yr on certain Audioquest Dragonfly threads as well as Currawong's posts on HF, some of the guys in JP have been using some products like the Aurorasound's Busmaster Pro/Ratoc Labs RAL-EXTPW01, thats why I bought one to try with my A3 late last yr.
I won't say the addition of such USB-conditioners/isolators will provide a 180 degrees change/improvement to yr existing USB-powered DAC, as I feel that the quality of the DAC still matters the most and I have felt the most impt chain in yr own desktop rig is actually the DAC itself. But I can def say with honesty my RAL-EXTPW01 has managed to add on some extra micro-details, with a very noticeable change in terms of adding depth/width to the soundstage and imaging details.
Bass extension/quality wise I nv noticed much changes with or w/o the USB isolator, but usually when we are talking abt bass quality it can be easily solved instead with a change of USB cable so I wouldn't rly worry abt that, if want can just buy another boutique cable if u want something more bassy/impactful.
Same likewise for treble improvement, I bought a Continental 5S from Oyaide, and although its a pure silver cable it's not necessarily brighter by alot compared to my Fostex/Zonotone copper cables (which I personally find is usually a myth often discussed on Head-fi), I would say maybe just ard 5% brighter compared to my prev cables. But what's most obvious to my ears with the adding of silver USB cables to my HP-A8 rig, I find that you can hear more details in the midrange/highs regions, and the overall response also became much more smoother.
Vocals became slightly much sweeter in tonality, not sure if that's a coloured characteristic of the Oyaide, but I didn't noticed much sweetness when it comes down to vocals rendition wise with my prev Fostex/Zonotone copper cables. (they are just slightly more bassy than my Oyaide thats all) You can definitely feel the outline of the vocal edges when the vocalist is singing much clearer with more focus on the outline of each spoken word, but it is not an overly sharp or sibilant kind of outlining, you can just feel the edge of the vocalist's voice better. (with the prev Fostex Zonotone cables, the notes has a slightly more rounded feel to it, not as crisp/sharp)
Yes, your previous suggested connection setup for the HP-A4 to yr ALO The PanAm is correct. PC to USB input, then from HP-A4's RCA/Phono out to yr PanAm, thus using yr PanAm for amplification instead. HP-A4 does have optical toslink input, so if you happen to be an Apple user using Macbook Pro with built-in optical on its headphone jack, you can just use one of those converter cables to feed the signal digitally via Toslink.
I have no idea what's the purpose behind the microSD slot on HP-A4, because according to press coverages and previews leaked so far, it doesn't have a remote ctrl bundled with it. But on the HP-A8, there is a direct SDcard slot at the back, for you to playback 1-bit DSD/WAV files directly through an SD memory card, and that memory card can also be used for firmware updates.
I suppose the microSD slot on HP-A4 may be serving as ease of firmware updates, in case the owner has no access to a PC during that time, that or my guess is Fostex may be bundling a remote ctrl for this product afterall, which means u can playback high-res music via just a microSD slot while outside w/o an actual laptop, which is prolly useful when attending audio meets I guess?
Just some of my own thoughts.
