QUOTE (Arnold B. Krueger @ Sep 29 2009, 13:13)

There is also an approximate 1.8 dB difference in average RMS level.
I noticed that the average RMS levels differed by amounts that were significantly different from the difference in peak values. This may indicate that one of the DACs had considerable nonlinear distorion and thus failed the criteria of being "a good DAC".
The supplied samples pretty much *have* to sound different because of the apparent RMS level mismatch.
Once I corrected for most of the level mismatch, the spectral responses were nearly identical over the range from 40 to 16 KHz, and varied only by a fraction of a dB outside that.
Would you please re-post them with your changes?