left image is IBVA direct ( mean use IBVA AD )

right image is Mac Sound Line input ( mean use Mac AD )

both same brain head amp that inside of IBVA, however to Mac sound line input is no high cut filter.

IBVA setup is 960 Hz sampling, 320 Hz -3dB high cut filter

direct out is 1000 Hz -3dB slow high cut filter.

Test with 200 Hz sin wave.

from IBVA direct output, connect to Mac line input use 3 K/200 ohm + 2.2 µF

from IBVA direct output, connect to iPhone mic input use 3.1 K/15 ohm + 22 µF