Location: London/Durham
Posts: 6,878
I'm Lawrence.
I actually have two pairs of the Yamaha HP-1 Orthodynamic headphones in question and they do require a little more driving than moving coil types. Very good sound quality though, a little reminiscent of electrostatic phones. And no, I wasn't thinking of selling at the moment.
2 YHA Yamaha sets on t'bay currently.
Chris.