Much like a difficult opera singer, the 56 tube requires a perfect environment to perform. But when the bias is right and the shielding is perfect, the vocal reproduction is unparalleled. The Technical Specs
Always use a soft-start circuit to protect those precious 1930s filaments. Prima Donnas: 2x56
Use tube dampers or high-mass isolation platforms to combat microphonics. Much like a difficult opera singer, the 56
In audiophile circles, this specific 2x56 setup (meaning two Type 56 tubes acting as the heart of the preamp or driver stage) is called a Prima Donna for three reasons: Much like a difficult opera singer