Help with Buttkicker Gamer 2 setup.

[Bocoloco]

Hi,

Coming from a ps4 and I want to use my buttkicker gamer 2 with PC.
I have my TV connected via HDMI to PC and the buttkicker amplifier via HDMI to RCA Converter. Is there a way to connect the buttkicker direkt to the PC I have no extra Soundcard only onboard sound. I don't use speackers only a stereo Headset connect via 3.5 plug to the TV.
Because wenn I connet the the headset to the pc there is nothing coming out of the buttkicker. If I connet the buttkicker amp to center or sub out to the pc an go to the sound manager an test it reacts but in game nothing. What do I have to change?
Thanks for Your help.

Claude