yeah, I'm also having all sorts of thoughts about what to improve and how...but if your primary use is speakers, you will gain far more by putting that money into DRC and foamy bass traps and so. It also boils down to what S/PDIF receiver your DAC uses?
I've also read raving feedback about that USB cable you just mentioned, but their sales pitch is the usual blabla WW has been using since forever, and my $4 Lacie Flatcable also has discrete power and data lines
Personally, I'm looking into feeding isolated I2S to the DP-1, but isolation adds distortion and jitter...whatever via coax, USB or I2S: http://hifiduino.wordpress.com/2011/11/24/which-digital-isolators-for-i2s-or-not/
I've read on the rock-grotto forum that isolated I2S sounded more laid back than non-isolated off the very same board, so I'm afraid that it could veil the trebles like ADuM4160 does. And strangely the Stello U2 had a I2S output, but not the U3...but I guess it wasn't isolated anyway.
I also read many ppl stating that pulse transformers over coax would add jitter and color the sound, which makes sense as nothing's free in this world.
The PSU input on your Olimex dongle goes through a switching-mode regulator, so there is little point in using anything advanced. Olimex told me that I should tap any serious PSU directly onto the USB output power pins.
To get back to this $350 USB cable supposedly sounding OHMAGAD-IT'S-LIKE-THEY'RE-SINGING-IN-MY-ROOM, it might very well be the case...but it's like those $50 gold plated fuses, even if they sound "better" someone is obviously getting ripped off badly. You can rest assured that they get those USB cables for less than $5 in Shenzhen and those fuses for 50 cents or so. I've spoken w/ cable believers who told me that the actual cost didn't matter and that they were paying for R&D, giving me the totally off-topic example that when you buy a piece of art you don't ask how much its actual cost was.
There are some hi-speed USB2 isolators, but they use optical isolation so it will be a jitter feast, haha.
Edited by leeperry - 12/11/11 at 3:24am