This can’t be… I always (really always) set “Residual level” to zero, so the wet one should be the only output. But, if I also set the wet level to zero, the output should be nothing. But the output was hard clipping. If I set the wet level to the highmost value, nothing was been changed. Any values between made a softer clipping.
I lived with that magic and I never questioned it. It worked for years
Now, I search for the old hard limiter and found this:
Look here: http://ttmanual.audacityteam.org/man/Hard_Limiter
So it was NOT a wet/dry mixer . (but now I know, what the third slider did
)