Disclaimer: I am out of my league when talking headphones. I’m just throwing this out there.
From what I understand, you’re currently connecting your Benchmark DAC 3 HGC to your preamp using the RCA connections. That leaves the balanced outputs on your Benchmark DAC 3 HGC unused. So, here’s my thought.
Why not set your equipment up in the optimum location using shorter RCA connectors and then buy a headphone amp for your couch area, which would be hooked up via the balanced outputs between your DAC and the headphone amp?
I found a headphone amp on Amazon for $289. Just search under:
S.M.S.L SH-9 Headphone Amplifier THX AAA Technology RCA/XLR Input 6.35MM Balanced Headphone Amplifier
I also found a headphone amp (not on Amazon) for $7,000. So, you have choices.
Try posing this question under the headphone section of the forum. You might get some good suggestions there.
Toolbox