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Happy 100th To The Vacuum Tube
williamw83 writes "Today, November 16, 2004 has been declared as the centennial of the birth of modern electronics by the American Vacuum Society. As the AIP Physics News Update reports, this marks 'British scientist John Ambrose Fleming's 1904 invention of the first practical electronic device. Known as the thermionic diode, this first simple vacuum tube, containing only two electrodes, could be used to convert an alternating current (AC) to a direct current (DC).' Today's celebration takes place as part of the AVS's 51st Annual Symposium & Exhibition in Anaheim, CA. Being a guitar player myself, I've come to truly appreciate the technology of the vacuum tube every time I crank up my amplifier. This 100-year-old grandfather of electronics, used by musicians and audiophiles across the world, has proven that profound advances in technology do not always render old technologies obsolete."
Lets not forget the single largest use of vacuum tubes today, the CRT (cathod ray tube). There in your old TVs and moniters.
Also every radio station and high power transmission you listen to is transmitted by large vacuum tubes. Silicon may never be able to replace these 10KW+ monsters.
Are you talking about sound PROduction, or sound REproduction?
If you are talking about production, what you say is true. Electric guitars sound "better" with tube amps, because thats how they sound. The player is not "distorting" the sound, the guitar+amp is the sound. A harmon mute "distorts" a trumpet sound, but when you are trying to make that sound, kick ass.
If you are talking about sound REproduction, bullshit. Discrete transistors distort the signal less, and you are trying to play back the recording AS CLOSE AS POSSIBLE TO HOW IT WAS RECORDED. Transistors will do that better then tubes, and have done so for decades. Tubes will fuck up the signal.
High power RF amplifiers. Tubes have several advantages here, better high frequency response, can run a LOT hotter and are typically more electrically rugged (i.e. a tube can recover from an arc).
A Shadeless room is a brighter room.
When high power semiconductors fail, you need to worry about shrapnel. When high power tubes fail, they look great on a shelf.
Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
Since relays are inherently switching elements as opposed to amplifier elements, they did not need resistors; the only necessary resistance is the one inherent in the relay coils themselves.
The Fleming diode might have been the first electron tube (valve) but it was Lee De Forest who put in a control grid between the filament cathode and the anode plate and created a device that could amplify voltage, which made the whole world of useful electronics circuitry all possible. The 100th anniversity of De Forest's "Audion" triode is not until 2007.
Telephone switches and relays were reliable and remanined in service for decades. Bell had a functional elecro-mechanical calculator using 450 relays with teletytpe output in 1939. Ballistic calculators built for WWII had 9000 relays, and there lies the problem. 9000 vacuum tube relays are power-hungry, hard to cool and need constant replacement.
Your statement about distortion spectra is a funhouse mirror of the facts. Harmonic distortion is harmonically related. Transistor amps, having much higher open loop gain and therefore much higher feedback (which is how they achieve those low distortion numbers, some of the most linear simple gain devices every made are low gain 1930's direct-heated tubes) will have a harmonic distortion content shifted much higher because of it than typical tubes but it's still based on the excitation signal. Bass signals don't magically generate distortion between 10 kHz and 20 kHz. And this is far from an advantage, the least audible distortion is second harmonic. Higher odd-ordered harmonics are audible at levels much, much lower than second.