The only shortcoming of this design for some is it's single RCA input. No problem though if you are using a DAC directly connected or in my case , my preamp's TAPE OUT is feeding a fixed level input to the Quicksilver. I'm lucky I guess that my preamp Tape Out is wired directly to the input. My preamp does not have to be on to pass what ever is present at its input appears at Tape Out. This most likely would only be the case with an analog preamp, i would guess anything micro processor controlled does not pass a signal when its off.
If whatever you are feeding the Quicksilver with has a variable volume control in the digital domain, set it to either "fixed" or " 0dB" or a little below for best results. Keep AC cables away from its input cables and it should have a nice quiet background. I had noise when I first set mine up and it was just poorly shielded interconnects. Swapped them and nice and quiet. Remember, you are listening through headphones , so anything to lower the noise floor is worth the effort.
Enjoy, it is a great sounding amp. I bought mine sight unseen, but having Quicksilver amps , knew it would be awesome. Wait til you lift it out of the box, it is a monster. Once you pick it up, you will know your money was well spent before even plugging it in... one caveat, you will be upgrading headphones a few times over the next year.... actually, you will keep your existing phones along your upgrade path because they all sound better powered by this amp. Post feedback once you've spent some time with it