Hi Jibzab,

welcome to Questions & Answers..

Could you give us some more info please..

My Sony DR-GA500 headphones work perfectly, but when I connect them to the Sony DP-GA500 processor it won't give a sound.

You state the headphones work perfectly but not when connected to the processor..

Are you connecting with the USB cable or Multi channel cable.?

Have you checked the input switch matches your set-up .?

Do any of these troubleshooting tips help -