I have a Burson HA-160 headphone amplifier (in pics, on the bottom) and the Burson AB-160 Audio Buffer (in pics, on top) that I am selling. there is a very tiny scratch on the top of the HA-160 amp from a previous owner, but it is barely noticeable. The Burson amp has been written about a lot recently and it’s a really amazing amp that produces a nice wide soundstage, great details and a great sound of attack that, imo, pairs well with Grado’s aggressive sound signature. The audio buffer eliminates impedance mismatching and helps add that last 10% to the transparency and detail of the sound. It’s not a “night and day” difference without it there but it can provide a little improvement depending on the speakers or amp that you connect downstream and the source you plug into it. edit: SOLD!