It's amazing that this old headphone still can compete. With a few mods it gets even better. Just listened to some acoustic guitar that sounded very present with resonating strings and an expansive sound stage.
I've repaired my favourite pair (broken parts, bad driver conncetions) that once was owned by a not very careful person.
This is what happens when you try to open the side cap without loosening the screw under the number plate:
I fixed it...