Hi, A MSB Link Dac 3 sells used for some where in that range and is upgradable with an upsample option as well as an outboard power supply.They can be factory upgraded to full nelson verson.Modwright as well as others do upgrade mods.These units are good sounding rigs and can be upgraded as money allows.And as another post states: Musical Fidelity A3 24 for a few more Bens($100 bills)is a fine unit.I hope this helps. Gixerman