Conclusions thus far: Measurement behavior hard to predict or extrapolate from one measurement to another - some odd behavior and interactions. However, steady state distortion measurements too low to make a difference or tell us anything that we can correlate to human subjective perception. Roll off on the high end starts gradually at 10kHz and is down -4db at 20kHz. Hard to say if people can hear this. I think I can. "Preamp" should still be treated as digital attenuation where we still want to keep the attenuation to a minimum. Subjective Impressions Here: https://www.superbestaudiofriends.o...gital-audios-morpheus.9093/page-2#post-298790 https://www.superbestaudiofriends.o...gital-audios-morpheus.9093/page-3#post-299204 I am having some issues with balanced output measurements at lower levels from combination of specific gear, verified with other measurement gear I have on hand, so just showing SE output measurements for now. AES input used below. (EDIT: I figured out it was a grounding issue - bad AES cable. BAL measurements here: https://www.superbestaudiofriends.o...heus-dac-measurements.9275/page-2#post-299929). 0dbFS - full scale 1001Hz SE out -30dbFS 1001Hz SE out -60dbFS 1001Hz SE out -90dbFS (toggle of smallest bit for CD quality content) 1001Hz SE out What's interesting is the behavior of the lower level test tones, much less distortion and AC noise. Also the excess grass (at 1001kHz) is discussed here: https://www.superbestaudiofriends.o...t-morpheus-dac-measurements.9275/#post-299776.