Completely agree.
Same here. I was impressed by the sound quality improvement over the GD m900 within the first minute, before playing around with the multitude of features.
Completely agree.
I heard the SE out should eb the same between DAC and Pro. Not sure if the balanced out in pro is an improvement over the DACNote that the 'DAC' has been a 'DAC FS' from the beginning, it was the Pro later being updated to FS. I doubt there is a sound difference. IMHO it's more about a different feature set.
The EQ's effects the line out and balanced output as well as built in headphone amps. So the effects are not lost. It has a range of +12 to -12 DB. I don't know what headphone amp you intend to hook it up to, but this Headphone amp would significantly outperform the Magni in your sig. Unless you have some much higher end gear your hiding, the ADI-2 would replace and make your entire stack rather redundant. Outperforming it in every regard, though it should at triple the cost.
Im not sure what your question is, but I own the PS Audio Duet, the ADI-2 DAC FS, and the Liquid Platinum. It's a good pairing. Im pleased with it, and the liquid platinum is a nice amp for a bit of tube flavor. The built in ADI amp is also quite good if your after flat solid state, clean sound. They compliment each other quite well, as the ADI-2's volume control is a nice/necessary feature for the Liquid Platinum, which lacks gain control. The LP's a bit more dynamic then the amp in the ADI, and of course tubes add flavor, as does the PEQ feature in the adi-2. Im not a huge believer in power products, but I do believe in buying a product that does two things.. A. protect's your gear, and B. does no harm, and I believe PS audio's power products do this.