Have been running it w my PC, a Cambridge DAC Magic and AKG 701's

Any experience with recappping and power supply upgrades? I'm tempted to see where a few mods and some tube rolling will take me.

I bought it w the AKG 701's for $450 so I feel I can afford to tweak it. Is there an out of the box tube headphone amp or better amp/dac out there for under $1000 used to consider?

Ideas appreciated.