Pricing for B&K AVR 305 w/ upgrades

I'm looking to switch to a headphones only setup (Stax) and I want to get rid of my B&K AVR 305 w/ upgraded software and DAC as well as the rack mount. The unit is in perfect condition with the except of a 1cm scuff on the control knob. eBay hasn't been a very reliable source for this model and I'd like to get ~400-500 for it. Anyone have any suggestions ?