I've used winetricks with the following command:

WINEPREFIX=~/.steam/steam/steamapps/compatdata/205190/pfx winetricks sound=alsa

then connected the real tone cable and deactivated it in pulse audio:

pavucontrol

and in "Configuration" turn the "Rocksmith Guitar Adapter" off. Finally I had these values changed as suggested to run Rocksmith 2014:

sudo nano /etc/pulse/daemon.conf

and edit the two values:

; default-fragments = 5
; default-fragment-size-msec = 2