heres a test i did of mic/line input noise at various levels
level adjustments at (approximately, the one at 1:00 is a bit late...like 1:10)
0:00 = 0 input level
0:30 = 5
1:00 = 10
.
.
.
8:30 = 85
9:00 = 90
9:30 = 95
10:00 = 100
you can see the level adjustments by the ticks (remember- its a feature!) which are sometimes worse than others
as you can see the noise isnt too bad but gets pretty high above 80% input level as kind of expected by this cheap consumer pre-on-a-chip
looks pretty solid up to 50 input, would not run above 80 in any case
that was with an empty cable, ill try it with an actual load like a clean ADC being fed zeros
some statistics in soundforge
input level, RMS level (peak level)
0, >93dB
10, >93dB (peak 80 dB)
20, >93dB (peak 79 dB)
30, >92dB (peak 79 dB)
40, >90dB (peak 76 dB)
50, >87dB (peak 73 dB)
55, >84dB
60, >90dB (peak 75 dB)(is it switching circuits internally here?)
70, >87dB
80, >84dB (peak 65 dB)
85, >75dB
90, >68dB (peak 53 dB)
95, >68 dB
100, >65 dB (peak 47 dB)