This may seem odd, but we're so pleased with the BerryDigi/Pi combo driving our main system that it makes economic, audiophile, and Alpha-Geek sense to consider a Pi/Berry-amp setup to for our headphone listening.
Assuming that the Berry-amp is supported in the current Raspbian Kernel, then it should be compatible with either PicoPlayer or Squeezelite - which are our preferred media players, yes?
We're comfortable building a resistive dividing network if we need to pad down the Berry-amp's output - but since we're using moderately inefficient headphones (Fostex T20 V1 - 50 Ohm, and Sennheiser HD580 - 300 Ohm) with good power-handling, and controlling volume in the digital domain, it doesn't look like an issue.
Yes, we could make up a Pi/BerryDAC setup and then feed a quality analog amp like an O2, or Bottlehead - but since our main pure-digital system (Pi/BerryDigi => MiniDSP NanoDigi => HiFimediy ddx320v2 amps => ML Sequel II's) has been a real eye-opening experience of rock-solid images emerging from an inky-black sonic field) we'd like to pursue this concept for headphones too.
Berry Amp for headphones?