There are threads about the noise floor (see below). Most people don’t have a problem. Most that did chose to address it with one or more of the recommendations. I’m sure some don’t wait until their unit is broken in before making up their minds. This is expected - but the DSs take longer than most pieces of kit to break in.
My most recent post on this topic:
https://forum.psaudio.com/t/fpga-improvements-in-redcloud/4482/56
In this thread:
https://forum.psaudio.com/t/dsd-dac-very-faint-high-frequency-noise/2476/8
An older DS Jr post - Since then Huron lowered ultrasonic noise:
https://forum.psaudio.com/t/from-junior-high-frequency-noise/3980/6