Interesting how amp designers make their tube choices…my Raven Blackhawk uses 2-12AT7 for the preamp stage, 2-12AT7 for the power amp first stage and 2-12AU7 for the phase inverter. When I rolled tubes in my preamp stage other favorite 12AT7’s behind the Brimar 6060 Yellow T’s were early 70’s Tungsram with an unusual rare square shiny metal getter support, ‘50’s Mullard with the square getter and ‘50’s RCA and Raytheon black plates. Amperex and Telefunken the highs were a bit edgy and thin for my liking. This is all based on my amp, my system and my preference for a smoother warmer sound with rich tone listening mainly to blues, jazz, soft rock, folk….
