OK, these may be dumb questions, but reading 50 pages of this thread hasn't answered it, and the landscape seems to be changing with the release of the V3...
1) Does the DI-V3 up/downsample? As it lacks a DSP, I don't think so, but want to confirm. As do most of us, I have a lot of music in 16/44.1 FLAC, plus a bit in 24/96 and very little in 24/192. I want to be able to output all those sample rates to my DAC. I think the V1 and maybe V2 would resample everything to 24/96, which I would prefer to avoid. Does the V3 offer bit perfect output?
Kingwa: The DI V3 have not hardware upsampling, if in PC, it can setting the output sampling while DS output model. Other output model it output is original sampling.
So my take is that the DI V3 does no upsampling/downsampling and passes through the native rate. Given that users of the Squeezebox Touch EDO mod have reported it works with 192 files, this makes sense. One of my big concerns about the Empirical Audio Synchro-Mesh (apart from the price) is that everything is resampled to 96, and even native 96 files are resampled, so there is no such thing as bit perfect output.
2) In terms of jitter reduction capabilities, do I need to connect my SB Touch (with EDO for 24/192 output) to the DI via USB to take advantage of asynch USB, or would using coax SPDIF offer the same quality? As I do not HAVE to use USB with the Touch, I'm wondering if it is worth the additional hassle vs. using just coax digital.
Kingwa: I ever got some users feedback the USB connect have better sound than the coaxial connect.
I'm not sure what to make of this, except that it might be worth trying both the USB and coax connections to see what sounds better to my ear.
3) Does the DI's external PSU need to be turned on and off for listening, or can it be left on all the time? My family needs the stereo to be as simple as possible, and having to manually turn on more devices is not going to work. Plus, having the DI powered on and off might cause problems with the Touch (I've read that users with DACs that power up and down have issues keeping a connection).
Kingwa: The DI alway select on DC input, the total power ON/OFF control from the DI-PSU. Because we have design the DI have not applied the +5V wires in the USB cable for the better sound, so we are advice users if keep it always power on, while restart the computer , restart the DI is better.
My understanding is that when the DC input is used (with the PSU) then the DI does not draw current via USB. Also, you should restart the DI when you reboot your computer. In my case, I plan to leave the Touch plugged in (it will sleep but that doesn't mean it is totally off), and will just leave the DI and PSU on 24/7 as well.