I own a pair of [original] Koss ESP 9 electrostatic headphones. They originally came with “liquid filled” ear pads. The pad are long gone. I think their sound is very good. Their energizer unit is connected to my Anthem 1120 receiver. I am unable to wear them for any longer than 45 minutes to an hour. They’re very uncomfortable. I was wondering if anyone owns a pair and your thoughts about them?