Those headphones should not need an amp to drive them, is the cable inserted all the way on both sides? Did you make sure the volume is up in Windows and the program you are using to play the sound? Try them on other devices?
Those headphones should not need an amp to drive them, is the cable inserted all the way on both sides? Did you make sure the volume is up in Windows and the program you are using to play the sound? Try them on other devices?