AudioBahn Amplifiers Using Transistors and Vacuum Tubes

AudioBahn Amplifiers can be implemented using transistors of various types, or vacuum tubes (valves).

Transistor

A transistor is a semiconductor device that uses a small amount of voltage or electrical current to control a larger change in voltage or current. The transistor is the fundamental building block of the circuitry that governs the operation of computers, cellular phones, and all other modern electronics.

Because of its fast response and accuracy, the transistor may be used in a wide variety of digital and analog functions, including amplification, switching, voltage regulation, signal modulation, and oscillators. Transistors may be packaged individually or as part of an integrated circuit chip, which may hold thousands of transistors in a very small area.


Vacuum Tubes

In electronics, a vacuum tube or (outside North America) thermionic valve or just valve, is a device generally used to amplify, switch or otherwise modify, a signal by controlling the movement of electrons in an evacuated space. For most purposes, the vacuum tube has been replaced by the much smaller and less expensive transistor, either as a discrete device or in an integrated circuit. However, tubes are still used in several applications such as in audio systems and high power RF transmitters. Cathode ray tubes are used as the display device in television sets and computer monitors, and magnetrons are the source of microwaves in microwave ovens.

The vacuum tube is a voltage-controlled device, which means that the relationship between the input and output circuits is determined by a transconductance function. The solid-state device most closely analogous to the vacuum tube is the JFET, although the vacuum tube typically operates at far higher voltage (and power) levels than the JFET.