Audio setup gone wrong?

May 10, 2018
Please help me I will paypal some cash to the person who can! :)
Iv just purchased the SMSL sd-793ii (Amp/dac) http:// with the hopes i could connect to my pc and then connect my new beyer dynamic dt990 (250ohms)

Upon connecting it all and powering iv been unable to get anything working .
My sound is run via the motherboard i assume. (not installed a soundcard myself)
The past headsets iv used have been headset/mic combos like the corsair void wireless. I wanted to upgrade to headphones as I use a mic on a boom now rather than a headset mic.

I purchased a cable i believed to be correct - http://

But no joy, there are coaxial,r out and L out on the back of the AMP/DAC. I read on a post that this amp dac would be efficient to power my headset easily. Is there a cable i can buy that will connect my pc to this amp/dac via either the coaxial and a 3.5mm jack,optical and a 3.5mm jack or the red and white audio.

Please help me guys