I have tried a few well thought of vintage cans and they have been notably opaque and also usually rolled off at the top end (which is a mercy, as the top end is often quite grainy). A decent modern pair will be easily superior imo. Then again some people like ancient and outdated speaker designs like Tannoy.
I guess an appropriate vintage headphone could be good for some genres, like rock, where the solidity and power of a good vintage design can be impressive, and you're not too fussed about delicacy, openness and transparency. I'm thinking vintage Koss, for example, their 4AA fits that description like a glove imo.
Having said all that, if you can get your hands on a pair of Wharfedale Isodynamics grab 'em quick - fantastic things! Easily the equal of the lower end of modern planar magnetics although they do lose out in the bottom octave of bass. But they are very inefficient and need serious amounts of power and gain.
Thanks J - those look good but I'm sticking with closed back at the moment so I don't annoy others in the living room ...
BTW I'm going to try a different Topping solution from the one we discussed recently - a two box solution isn't ideal for me especially with the dual power supplies and lots of cables.
This is their NX4 DAC / headphone amp which although designed to be portable should make a very good desktop unit from what I have been reading - it's also extremely low impedance at just 0.9 ohms so will suit my cans very well indeed.