Others have posted that the DA 100 runs hot also, but mine runs barely warm (8-10hrs at a time)unless the ambient temp goes over 80F, at which time all my equipment heats up... I do not upsample and have both optical and USB connected.
Are you using the 192 feature? How old is your unit? How quickly does it reach what you would call very warm/hot? How do you have it connected when it runs hot... opt, USB, coax or as you posted above? Is it well ventilated or surrounded by other equipment?
I'm just curious about this... I have it on a perforated stand next to a Woo3 with a GS-1 under it... Don't know why some of them run hot....
Regarding the volume level, I find both my GS-1 and Woo3 are comfortable at 9:00 too.
Regarding the cables, although I have great respect for his input, I have to disagree with Andrew, placebo effect, unsupported by any measurements.... just get good short cables. I use Dayton 1.5ft.
On the other hand, if you believe in "cables" by all means get some, I'm sure you will hear a difference.
After all, it's only a hobby...
I think the ventilation around my DA100 pretty good. The Gilmore Lite is 3 inches to the left of it, and nothing to right or top of it. I have a Pioneer A35R integrated amp below the DA100 but it only gets slightly warm. Having the integrated amp on or off does not affect the heat of the DA100.
I do use the 192Khz upsample. I have coaxial and two optical connected to it. Only one of them are active at any time.
I don't really believe in expensive cables. I think cables that are above the ones that come free with equipments are fine. Having said that, I still want to try it for myself. I'm just too curious. So when I get some more extra money at the end of this year I will try the Signal Cable Silver Resolution and Audioquest King Cobra.
EDIT: Today's a bit cooler at my house. With ambient room temperature at about 68F, the DA100 is just warm, not hot. Seems like everything is fine.