Do you know why no.390s output DAC for 24bit/192kz data have some harmonics? see stereophile review : The top pair of traces in fig.2 shows a spectral analysis of the No.390S's left and right outputs while it decoded CD data representing a dithered 1kHz tone at -90dBFS. The spectrum peaks at exactly -90dB, implying excellent linearity, while the noise floorâ€â€almost entirely due to the recorded ditherâ€â€is free from power-supply- or distortion-related spuriae. However, I also drove the No.390S's data input with 24-bit data representing the same signal; the result is shown in the lower pair of traces in fig.2. Usually, the increase in bit depth drops the noise floor, revealing the component's true resolution. This is true for the part of the spectrum below the signal frequency, where the noise floor drops by 9dB or so, implying DAC performance close to 18 bits. But above the 1kHz signal frequency, peaks appear at 3kHz, 5kHz, 9kHz, 15kHz, and 18kHz. The only possible interpretation of these odd-order distortion components is that the No.390S truncates external data to 16 bits. [IMG]http://www.stereophile.com/images/archivesart/390FIG2.jpg[/IMG] Fig.2 Mark Levinson No.390S, 1/3-octave spectrum of dithered 1kHz tone at -90dBFS, with noise and spuriae, 16-bit CD data (top) and external 24-bit data (bottom). (Right channel dashed.)