Thanks to all for the replies. I would seem a balanced isolation transformer, feeding all components, is a viable solution both with regard to size and noise level - disregarding cost, not that I believe it'll be an excessive figure. I'll have this in mind, and consider such a solution in the near future.
Yesterday, however, I made a (seemingly) minor correction with the ISO transformer over the DAC-9 that addresses my quibbles on the slight softness and rather center-focused presention; earlier when I started out with an ISO transformer over my HTPC, the initial setup led to an overall sonic character(i.e., pronounced softness and center-focus) quite simliar to that heard when the second ISO trsf entered before my DAC a little over a week ago. The friend of mine who'd been the "architect" of this initiative had in the meantime found out (first and foremost through hearing) that the wiring of the ISO trsf, and how they were hooked up with the lead- and return-wires to both DAC and outlet(secondary and primary side respectively), had significant impact on the sound. Being that our ISO trsf's were alike(same brand and wattage size), he relied on and found a way to (visually) localize the wires on the ISO trsf that were to be connected to lead and return(or 'hot and cold') on both sides, and once I had implemented this change over the HTPC, for a change it was, the sound fell into place: the soundstage opened up providing a more evenly distributed presentation, and a natural "edge" had found its way back into the sound as well. All was good.
Now, the ISO trsf I had used over my DAC to begin with, for I replaced it yesterday, was of the same brand and size, though the wiring(two yellows) on the secondary side was placed physically different and in such a way to make it hard(in effect, impossible) to differentiate them and determine which one needed to see the lead- or returnwire(also, the particular ISO trsf seemed to be of a different batch judged by the color of its label). I therefore wondered whether the wiring on the secondary side here had been swapped in regards to producing the desired sonic outcome, even though I had loosely assumed they were connected correctly. While it would have seemed most obvious to simply switch over the two yellow wires to see how that turned out, I instead opted for another similar ISO trsf I had been given(with the others), being that its wiring(i.e., their physical placement) equalled that of the one used over the HTPC exactly, indicating it might have been from the same batch as well(also judging by the label color). And sure enough, after replacing one ISO trsf with the other over the DAC-9 and getting the wiring right, the sonics fell into place as described above - and with everything sounding somewhat more full, clearly chiselled out, see-through, and organic/natural than before the ISO trsf entered the stage, so to speak.
06-02-12: Jea48
Phusis,
A test you may want to preform on your current ISO transformer is to check the AC phasing to see if it matches the AC wall outlet your other equipment is plugged into.
If the output of the ISO xfmr is in phase with the wall outlet there should be little or no difference of potential, voltage, between the hot contacts of the two receptacles.
If the two are out of phase the voltage will be 240V nominal.
Jim
Jim -
Perhaps you're addressing what I'm getting at above? But thanks, I'll try this out. I must stress that the ISO transformers I'm using only sports four wires (per trsf) in all, two on each side.