For the electronics enthusiast a tube audio amplifier makes for an interesting ... It follows a so-called ultra-linear circuit, with a tap on the output transformer feeding one of the pentode ...

After a brief review of the history of the K2-W vacuum-tube op amp, an LTspice model is used to create its schematic in ...

With the wealth of cheap and highly integrated audio amplifier modules on the market ... Especially when those parts include vacuum tubes, and doubly so when you make the vacuum tubes from scratch ...

Recognizing the nonlinear behavior of the 12AX7 vacuum tube, used in audio and old op-amp applications, Dr. Dyer compares various models for fit to real-world device data.