There are a few threads here you would do well to search for. A condensed version: Upgrade the power supply (the included wall wart is underpowered) remove the tube, terminate all the unused terminals on the back. There are others that are easy to do, there are some that aren't.
I've got a couple of DI/O's at various stages of modification. The modifications do make a difference that can be very pronounced, but the internal mods require some soldering and electrical skills and a lot of patience.
Terminating the unterminated plugs is completely useless, dont waste your time on it, there is no difference... nor is there a difference in grounding the ground pin... at least on my setup...
Upgrading the power supply does make a quite difference though, a significant difference.... I use the Stancord unit. Take the tube out because it is easy to do, but there were arcing issues due to this so make sure it does not arc to the chassis (put some insulation around the tube socket and above at the chassis).
Something thats not metal, heh... teflon is great, but overkill... just any piece of nonconducting pad or tape or something lying around will do... I think the newer units address this arcing issue but I am not sure.
Arcing occurs when there is an enough voltage differential on two opposing terminals (in this case the tube socket holes and the chassis) so that air will act as a conductor and electricity passes through it. Essentially it is lightning... And it is a bad thing in electronics... So if you insulate the chassis, it is a hell lot harder to make electricity pass through the air and no shorts will occur or any other bad things. I suppose in this case there is not enough voltage for this to occur but still should be precautioned since tubes are known to use high voltage.
Haven't been able to hook up my DI/O yet - expect my Cambridge DVD 300 to arrive tomorrow so I can. The User's Guide specifically says in bold letters: "Only use the adapter that came with the DI/O." Are we sure that no damage will be done using a substitute with higher output? Would just like to be sure it's okay.
what kind of cables are you guys using for the ART the bolder cables? does it make a difference? I'm getting mine tommorow.
What difference does the stancor pwer supply make to the sound over the stock power supply? Digital cables make any difference?