duff138,
The Panny is a very good sounding receiver for stereo or HT use. I would not use it just for headphones, The best thing about the Panny is keeping things all digital. When you use the A/D or D/A convertors in it, it loses some of the magic.
For a headphone based system, I would suggest a good D/A convertor into a very good dedicated headphone amp.
I use a modded ART DI/O into mine. I have recently worked on a M-Audio SuperDac 24/96. This is twice as expensive as the ART in stock form but there is a lot more room inside for mods. It uses the same D/A chipset but the analog section uses 8 pin DIPs. There are a lot of choices for opamps for mods.
There is a used modded Mensa Level DI/O for sale here at AC for a very good price. A lot of folks also like the Scott Nixon or ACK DAC NOS designs.
I use a modded Radii HAP-05 tubed headphone amp. If you are not in too much of a hurry, I could get one for you. It sells for $500.00. Tyson has one as well. He seems to like it
