Would this happen to be a gray plate?

I have an RCA 6080 which smoother, but also veiled compared to my transparent sounding 6AS7. Some say that the Gray Plate is smoother. But I have been looking at the Mullard 6080 as a substitute. I find the GEC CV4079 to be interesting, and I read quite deeply into the tube rollers thread...

I am looking for the smoothest power tube for my custom made OTL tube headphone amp that still has good transparency (timber, harmonics, sounstage and imaging). I am currently using an RCA Black Plate 6AS7GA with the Mullard 6DJ8. Any suggestions?

Something that is rarely mentioned is that they employ plasma-evaporated ruby diaphragms!

1. JVC HA-D990 2. Grado SR125i 3. A cheap pair of Panasonics which work well with my portable bass amp.

I too have been using these headphones (since the early '90's), and need a source for new or compatible pads. They completely outperform my Grado SR125i's, being balanced, refined and transparent throughout its frequency range. The OP stated that they were rated Class-C, but I remember them...