I wonder if Telefunken actually manufactured a 6AS7? Many tubes, even top quality ones were sold as re-branded.
Example? The best 12AX7 tubes from Radio Shack were Telefunken (yes, a long time ago). Many EL34 marked as Dynaco, RCA, GE, Amperex or other names were manufactured by Mullard.
If it turns out the rave over Telefunken 6AS7 turns out to be (another brand here) chances are they can be bought for a fraction the cost.
Maybe Ralph at Atma-Sphere will see this and respond, 6AS7 is a tube he knows a lot about.
Example? The best 12AX7 tubes from Radio Shack were Telefunken (yes, a long time ago). Many EL34 marked as Dynaco, RCA, GE, Amperex or other names were manufactured by Mullard.
If it turns out the rave over Telefunken 6AS7 turns out to be (another brand here) chances are they can be bought for a fraction the cost.
Maybe Ralph at Atma-Sphere will see this and respond, 6AS7 is a tube he knows a lot about.