well I gotta say I have a old model Beresford thing that sounds very good to my ears, and could I suggest a set of sony v6 headphones , I got a set recently, they are good, no not the best or easiest to listen to , but still rather good at most things, but best of all £60 deliverd.
I also put a nice sony 780 mini disk to use at times for headphone duties, seems good to me ,
I used to use a Tascam dat machine for a headphone amp it was great , sadly I sold it , but I needed the space and the money.
lowendall