Well, my supply is pretty similar to that one guy's, it running buck/boost converters... but I think I will be fine as far as ground loops are concerned... Here's why.
My setup is: hu -> toslink cable -> DCX -> amps
The thing is, the only place I'm going to get a ground loop is between my headunit and DCX as both amps are running from isolated secondaries.
I don't think I'm going to get a ground loop down a toslink cable really. In fact there is someone who is running a very similar setup with an inverter powering the DCX, without issue.
I don't really like mains voltages in my car, hence using my DC-DC PSU I have lying around (otherwise I'd be tempted to pick up a small 50W inverter). I also plan to keep the Behringer SMPS in there also, and have a series of relays in the unit so I can use the unit from both mains and 12v.
