Further listening: After some time of listening to more songs, I noticed that there are more pluses to minuses effects. For one, the highs are definitely cleaner. Secondly, the mid-bass where the bass notes are also received a good improvement - they are more clear and don't get disrupted by the other sounds. Also, the sound is more natural on the whole despite being more noisy, plus the fact that lossless files did not exhibit the extra noise can only mean one thing,
Time to leave MP3 and migrate to loseless. If I can find them, that is.
EDIT: While trying to strip the rubber coating and getting past the aluminium shield, I realised that I could achieve the same effect by taping the power pins on the USB connector so as to insulate them. Did that in a minute and saved a cable (although the rubber was cut open and the aluminium slightly damaged).
It sounds differently now, and not all positively, might be placebo I hope. It sounds "less powerful", and more garbled, but that might be because of the song (and the SRS WOW effect). Despite this I seem to be able to hear more instruments, there is definitely less noise, and the highs response improved tremendously. Now all the cymbals/high-hats/ting-dlings are very clear and sustained.
Last week, our hero and friends couldn't wait any longer and just bought a USB hub with a power adaptor for $29 instead of the $24 it would've cost in a bid to solve the hissing problem that he has with his USB DAC. And instead of some cheaper, half-the-price USB hub he decided to go for one with 2A. (Pity the D-Link wasn't easily available; it is price similarly and has 2.5A)
Ok, there wasn't any hero, nor does he have any friends. They are all imaginary if any except for his soul mate/mistress - the computer. And it wasn't last week, but about a month ago.
And yes the hissing was solved for now, it only came back once or twice so far, instead of more than that every day. However, occasionally, I can hear the sound quality degrade, so I still need to plug out and replug the USB cable. But this is less annoying than the hiss and can be left unnoticed.
Thinking about this while replugging the USB cable, I decided to see what would happen if I offed the power adaptor (Sadly, this hub has no control circuitary whatsoever between the two power sources, meaning the light of the adaptor will light up even when the adaptor is not plugged in to the mains but as long as it is connected to the hub which is in turn connected to the computer. This means any noise generated from the computer still gets past, but at least the power strain is lesser. At least I already saw the improvement. But this is still irritating. And what happens if the power backflows to the com? My previous (badly regulated) adaptor already took out a USB port and hung the com/corrupted the HDD/forced 3 days of reformat and troubleshoot/and caused me to lose my just completed music composition. Big impact here, ouch). And so I did, and immediately I could hear a difference. There was a smaller soundstage and the treble was weaker and muffled and bass got a little muddy and weaker. This is on a 128kbps MP3. So I decided to do a side-by-side test with a FLAC. The (above mentioned) difference is audible, not obvious, but audible. And significant, for you may need a DAC one level higher to hear even such a difference.
So power quality (and amount available) really does make a lot of difference in audio.
And hence, my next project - a USB cable with the power wires cut off. I already threw the (failed-?) powered USB cable away unfortunately. This is to completely isolate the USB DAC's power supply from that of the computer. I hope to completely eliminate the noise and get better SQ.
BTW unrelated to this post but still related to audio, last Saturday I decided to connect my father's com to my subwoofer since he was reconnecting it (it is beside my desk and shares the same monitor/keyboard/mouse through KVM), and with My Music folder shared I decided to do an ABX test. The contender's VT1616, which is supposedly a relatively good chip (compared to Realtek, yup. Hey, VIA do make good DSPs, just that their own DACs are a little bit f-ed-up). It practically got owned by the NeoMini. Same things as always: wider soundstage, better instument seperation, tighter bass, cleaner sound. My dad agrees completely. And as expected, the NeoMini has less bass volume (despite being way less boomy) and less warm trebles (although it is less muffled too), because of the lack of a preamp. With a preamp the NeoMini's sound signature will definitely change, although I can't say if it'd be for the better, especially since I'm definitely not encouraging running an op-amp off a computer power supply, and the USB +5V at that.
And with my Belden 16 AWG speaker cables being burnt-in and giving a huge bass-boost, I'm loving my NeoMini USB DAC more and more, and thinking that $55 is definitely worth it. You should hear it practically pwn the on-boards and even SB Audigy; a new Sound Blaster Audigy Value already cost that much, and mine was the almost-full ES version which just didn't have the firewire port.