Two fpgas are used on each of the da-7 dac boards. Compensation is done, that's been mentioned. I think 0.01% resistors are used. Good enough given compensation. Two fpgas are used on the digital board to handle the inputs and fifo reclocking. So the r2r 7 is a six-fpga dac, and the da-7 modules are even two-sided (there are approximately 800 precison resitors used counting both boards). So you are talking high-end implementation. You know your money is not going to marketing, distributor and resellers when popping up the hood. Check the nad m51 on the other end.