here's the difference between DAC1 and DAC1 Deluxe:
The chassis is copper plated steel. Separate digital and analog boards - each with its own transformer - are used, along with five voltage regulators. A Crystal Semiconductor CS8412 "E" Version receiver and CS4328 DAC are used in the DAC-1. The CS4328 is an 18 bit system, which includes 8X oversampling digital interpolation followed by 64X oversampling, one-bit, delta-sigma modulation - a lot of technobabble that translates to killer sound. For $250, the standard DAC-1 can be sent back to McCormack Audio and upgraded to the Deluxe Edition which has Cardas Jacks, Caddock and Vishay resistors, some high speed, soft recovery diodes, different op-amps, and some FET current sources to push then further into Class-A operation. Our unit had these upgrades (installed before the unit was initially shipped to us), and we feel it was worth the expense.