iqaudio dac plus on RCA ist to loud

Audio Gear DACs
1

Hi all,
and happy new year!
i have a IQaudiO Dac + on my RPi3 connet with the RCA to my Hifi amplifier.
But the sound is much to loud, just like for headphones.
any idea to get the normal volume for RCA output.
thx for help
r