Irrelevant

Hello everyone, First off - so glad this forum exists. I've been reading for days and there is some truly great info around here. I'm building a setup to listen my turntable with headphones that I also want to be usable for digital files from my laptop. I currently have Senn HD800s and the Senn HDVD800 DAC+amp. Question #1 (the dumb one): If I get a USB cord to connect my laptop to the amp, and buy a balanced after-market headphone cable such as this,is that all I need to get high quality "balanced" sound? Question #2: This one is on getting balanced audio from the turntable. If I get the cable mentioned above, I understand I'll have a balanced connection from amp to headphones. I also understand that the sound created from the turntable is "balanced". Therefore the only thing in the middle is the pre-amp. I currently only own the basic Pro-ject pre-amp, which only has RCA inputs. My questions therefore are these: Is it even possible to get "balanced" sound from the turntable through pre-amp through amp through headphones? If so, does this mean I need to get a "balanced" pre-amp and any recommendations? I have the Pro-ject Debut Carbon - does anyone know if this thing can output "balanced" audio? Thank you!