Now you're talking, you're in second place. I got my Koss Pro 4's in the 1960's to use with my Heathkit shortwave radio. For all of you tubies it was all tubes. I can't believe that they still make a newer version of them, in the same horrid green. Mine had a clamping force that could crack open a coconut. The earpads were oil filled rubber, I can still remember when one of them leaked on me, . Back then nobody argued about cables and I would have given my left ear to have something like an HD600.
Below is a picture of the new version, it looks eerily the same.
I had that headphone when I was a young teen. The fluid filled cushions really kept out any other sounds. At the time, that feature was important to kid with 7 siblings and a father that did not appreciate my taste in music. Really put you in your own world. These days, open phones are my choice.