[Arran]

Using twin triodes as a mixer and oscillator seems to work quite well, though I don't have any sets that use the XXL tubes I do have two AC/DC sets that use an XXD/14AF7. What I can't understand is why they decided to use a triode as a mixer, maybe another patent royalty dodge? I also can't figure out why they used a silly designation for a tube like XXL or XXD, that must have been the marketing department's idea just to make them sound mysterious then just calling them 7A4s or 14AF7s.
Regards
Arran