I use the 6AS7/6080 family of tubes as a cathode follower in a Wheatfield headphone amp (actually an upgraded version I modified myself with input from designer Pete Millett). Up until now my favorite tube in the cathode follower spot was either a 1960 RCA 6AS7 or a 1961 Tung-Sol 5998. The Mullard 6080 has a warmer midrange than either, and with my Sennheiser HD-800s it is my clear favorite among the dozen or so vintage tubes Iíve tried. The Mullard might sound too lush with other headphones like Audezes, but with the slightly clinical sound of the Sennhesier HD800, it provides what sounds to me like perfect midrange richness to along with the headphoneís amazing resolution.
Iím glad you found a source. I didnít even know Mullard made a 6080.....Anon