In the audio world, of course, we only delight in its awesome applications for amplifiers, preamps, dynamics processors and microphones, completely ignoring the fact that from the beginning of the 20th century for nearly 70 years, throughout the industrial age, vacuum tubes were at the heart of computers, industrial control systems, televisions, telephony, and virtually all data transmission from land, sea, space and air. Even the Apollo rocket program by NASA, while using early silica-based transistors in their computers and all other mission-critical electronics from 1960 onwards, used vacuum tubes in the radar and communications devices that tracked and communicated with America’s star-sailors. 

The first practical-use vacuum tube was invented by electrical engineer and physicist John Ambrose Fleming. Fleming made his breakthrough while working as an advisor for the Marconi Wireless Telegraph Company, who, until 1919 (when it became US-owned RCA), controlled nearly all radio transmissions in the United States. The idea was to create a component to rectify radio signals that would be more robust and reliable than crystal-based rectifiers in use at the time, especially on board seafaring vessels. 

Fleming applied for a patent for his “oscillation valve” diode vacuum tube on November 16, 1904, which was subsequently issued in September 1905. This Saturday, November 16, 2024, we celebrate the 120th anniversary of Fleming's remarkable achievement and the birth of tube electronics.

In 1907, standing on the shoulders of Fleming's patent, Lee DeForest developed a triode version of the diode design creating the first amplifier. DeForest’s design added a third element to Fleming’s diode by way of a helix of wire around the cathode, called the “grid”, which allowed variable control of the current between the cathode and the anode. By applying more voltage to the grid, more output voltage than input voltage was achieved, and the amplifier was born!

As more applications for tube electronics presented themselves, greater understanding of the technology brought ever more sophisticated and complex tube designs. Tetrodes and pentodes were developed with additional variable-voltage electrodes allowing the control of multiple functions. These developments led to the cathode tubes used in televisions, computers and x-ray machines.

The invention of Fleming’s thermionic vacuum tube heralded the beginning of the most significant period of technological advancement in the history of the world. Without the discovery and exploitation of tubes in ever more complex electronic applications, we would not have radio and television, global cellular phone communications, global internet, or computers at all. In fact, any device on the planet that utilizes electronic components and circuitry to perform its task owes its existence to the development of the vacuum tube. In the late 1960’s tube circuits were rapidly replaced with more efficient and less power hungry silica-based transistors and a technology that took decades to bring into prominence went obsolete within a year. 

The electronic age, and the modern world, owes its bones to the vacuum tube.

If you’re reading this, you really only care about how the sound of tube electronics enhances the experience of playing, producing and listening to MUSIC. Fender Bassmans cranked beyond the edge of harmonic distortion, smooth Fairchild limiters imparting their sweet, crystal clear sonic signature, a vintage McIntosh power amplifier’s super linear response through a pair of Tannoy Super Reds cranking A Love Supreme; the unique experience, today, of hearing the sweetness of tubes is something that just can’t be replicated by solid-state electronics.

Let’s celebrate the vacuum tube. Happy Anniversary!