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110-481: Though monophonic , the Ondioline is capable of creating a wide variety of sounds. Its keyboard spans three octaves, but by adjusting a register knob a player can render up to eight octaves. The instrument's keyboard is suspended on custom-designed springs , which enables a natural vibrato if the player manipulates a key laterally (from side to side) as that key is depressed. The keyboard is pressure-sensitive, and volume

220-421: A 2018 interview with Australia's Broadsheet , Gotye said, “You can dial in an incredibly wide range of sounds on the ondioline, and the unique mechanics for playing it allows you to create sounds very sensitively and with a musical deftness I just feel isn't present on most other electronic instruments from the '40s – or decades since." In 2022, De Backer launched a comprehensive website, Ondioline.com, devoted to

330-494: A DC power supply , as a demodulator of amplitude modulated (AM) radio signals and for similar functions. Early tubes used the filament as the cathode; this is called a "directly heated" tube. Most modern tubes are "indirectly heated" by a "heater" element inside a metal tube that is the cathode. The heater is electrically isolated from the surrounding cathode and simply serves to heat the cathode sufficiently for thermionic emission of electrons. The electrical isolation allows all

440-637: A blue glow. Finnish inventor Eric Tigerstedt significantly improved on the original triode design in 1914, while working on his sound-on-film process in Berlin, Germany. Tigerstedt's innovation was to make the electrodes concentric cylinders with the cathode at the centre, thus greatly increasing the collection of emitted electrons at the anode. Irving Langmuir at the General Electric research laboratory ( Schenectady, New York ) had improved Wolfgang Gaede 's high-vacuum diffusion pump and used it to settle

550-498: A combination of a triode with a hexode and even an octode have been used for this purpose. The additional grids include control grids (at a low potential) and screen grids (at a high voltage). Many designs use such a screen grid as an additional anode to provide feedback for the oscillator function, whose current adds to that of the incoming radio frequency signal. The pentagrid converter thus became widely used in AM receivers, including

660-484: A commercial success, and Perrey accompanied Trenet at concerts. Composer Juan García Esquivel used an Ondioline in 1959 on the recording "Watchamacallit," from his album Exploring New Sounds in Hi-Fi (RCA). The first American hit record to feature the Ondioline was " More ", by Kai Winding , in 1963. This instrumental version of the theme from the 1962 film Mondo Cane was arranged and conducted by Claus Ogerman , with

770-442: A cost-saving measure — in order to reduce the instrument's retail price — Jenny often used low quality parts; as a result, the instruments required regular maintenance or they would become unplayable. For decades Jenny redesigned and manufactured new versions of the instrument at his Paris company, Les Ondes Sonores Jenny (later known as La Musique Electronique). Later models offered such options as automatic vibrato and tremolo. There

880-579: A far superior and versatile technology for use in radio transmitters and receivers. At the end of the 19th century, radio or wireless technology was in an early stage of development and the Marconi Company was engaged in development and construction of radio communication systems. Guglielmo Marconi appointed English physicist John Ambrose Fleming as scientific advisor in 1899. Fleming had been engaged as scientific advisor to Edison Telephone (1879), as scientific advisor at Edison Electric Light (1882), and

990-446: A final mono mix, not to provide a stereo recording, although because of demand this was done anyway, and the early material was available on vinyl in both mono and stereo formats. In the 1960s and 1970s, it was common in the pop world for stereophonic versions of mono tracks to be generated electronically using filtering techniques to attempt to pick out various instruments and vocals; but these were often considered unsatisfactory, owing to

1100-505: A gas, typically at low pressure, which exploit phenomena related to electric discharge in gases , usually without a heater. One classification of thermionic vacuum tubes is by the number of active electrodes . A device with two active elements is a diode , usually used for rectification . Devices with three elements are triodes used for amplification and switching . Additional electrodes create tetrodes , pentodes , and so forth, which have multiple additional functions made possible by

1210-431: A heated electron-emitting cathode and an anode. Electrons can flow in only one direction through the device – from the cathode to the anode. Adding one or more control grids within the tube allows the current between the cathode and anode to be controlled by the voltage on the grids. These devices became a key component of electronic circuits for the first half of the twentieth century. They were crucial to

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1320-400: A low potential space charge region between the anode and screen grid to return anode secondary emission electrons to the anode when the anode potential is less than that of the screen grid. Formation of beams also reduces screen grid current. In some cylindrically symmetrical beam power tubes, the cathode is formed of narrow strips of emitting material that are aligned with the apertures of

1430-407: A mono system with a headphone output compatible with stereo headphones . An example of an application where both merged stereo and mirror mono apply is when a compact audio cassette respectively plays back "summed" stereo channels on a mono reading head, and when a compact cassette recorded with mono sound is played back with a stereo tape head. Other instances of "mirrored mono" also include using

1540-897: A new record label, Forgotten Futures, whose first release, Jean-Jacques Perrey Et Son Ondioline , was an LP of previously unreleased recordings of Perrey playing Ondioline. De Backer had befriended Perrey during the artist's long terminal illness and acquired the recordings from Perrey's private collection. "We got to know each other over a number of visits," said De Backer, "and through the time I spent with him in his apartment in Lausanne in Switzerland, he and his daughter Patricia started to produce all sorts of ... interesting early recordings that hadn’t been released — test pressings, alternative arrangements of things that are better known in his work. As I started to listen to these things, over time I realized this whole collection of stuff that he never really put out

1650-414: A pair of beam deflection electrodes which deflected the current towards either of two anodes. They were sometimes known as the 'sheet beam' tubes and used in some color TV sets for color demodulation . The similar 7360 was popular as a balanced SSB (de)modulator . A beam tetrode (or "beam power tube") forms the electron stream from the cathode into multiple partially collimated beams to produce

1760-412: A printing instrument was needed. As a result of experiments conducted on Edison effect bulbs, Fleming developed a vacuum tube that he termed the oscillation valve because it passed current in only one direction. The cathode was a carbon lamp filament, heated by passing current through it, that produced thermionic emission of electrons. Electrons that had been emitted from the cathode were attracted to

1870-409: A proprietary multi-A/V plug on the other end, which prevents automatic stereo merging unless adapters are used. Disadvantages of merged stereo involve phase cancellations that may have the effect of muffling the final sound output. If channels are merged after being sent through a power amplifier but before being connected to a loudspeaker, it places more stress on the loudspeaker . It has usually been

1980-506: A relatively low-value resistor is connected between the cathode and ground. This makes the cathode positive with respect to the grid, which is at ground potential for DC. However C batteries continued to be included in some equipment even when the "A" and "B" batteries had been replaced by power from the AC mains. That was possible because there was essentially no current draw on these batteries; they could thus last for many years (often longer than all

2090-452: A right-channel RCA plug (red) even if it was just for "merging" stereo into mono for mono soundtracks to be recorded onto videotapes. This is odd since one would think that a "right channel" would be included for A/V in on a TV which had MTS stereo TV sound on its tuner. Some stereo receivers will also include mono microphone inputs. Vacuum tube A vacuum tube , electron tube , valve (British usage), or tube (North America)

2200-407: A simple oscillator only requiring connection of the plate to a resonant LC circuit to oscillate. The dynatron oscillator operated on the same principle of negative resistance as the tunnel diode oscillator many years later. The dynatron region of the screen grid tube was eliminated by adding a grid between the screen grid and the plate to create the pentode . The suppressor grid of the pentode

2310-672: A single unified signal at a single place in the soundstage. In some cases, multitrack sources are mixed to a one-track tape, thus becoming one signal. In the mastering stage, particularly in the days of mono records , the one- or two-track mono master tape was then transferred to a one-track lathe used to produce a master disc intended to be used in the pressing of a monophonic record. Today, however, monaural recordings are usually mastered to be played on stereo and multi-track formats, yet retain their center-panned mono soundstage characteristics. Monaural sound has largely been replaced by stereo sound in most entertainment applications, but remains

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2420-419: A small-signal vacuum tube are 1 to 10 millisiemens. It is one of the three 'constants' of a vacuum tube, the other two being its gain μ and plate resistance R p or R a . The Van der Bijl equation defines their relationship as follows: g m = μ R p {\displaystyle g_{m}={\mu \over R_{p}}} The non-linear operating characteristic of

2530-405: A vacuum phototube , however, achieve electron emission through the photoelectric effect , and are used for such purposes as the detection of light intensities. In both types, the electrons are accelerated from the cathode to the anode by the electric field in the tube. The simplest vacuum tube, the diode (i.e. Fleming valve ), was invented in 1904 by John Ambrose Fleming . It contains only

2640-456: A vacuum where electron emission from the cathode depends on energy from photons rather than thermionic emission ). A vacuum tube consists of two or more electrodes in a vacuum inside an airtight envelope. Most tubes have glass envelopes with a glass-to-metal seal based on kovar sealable borosilicate glasses , although ceramic and metal envelopes (atop insulating bases) have been used. The electrodes are attached to leads which pass through

2750-400: A very high plate voltage away from lower voltages, and accommodating one more electrode than allowed by the base. There was even an occasional design that had two top cap connections. The earliest vacuum tubes evolved from incandescent light bulbs , containing a filament sealed in an evacuated glass envelope. When hot, the filament in a vacuum tube (a cathode ) releases electrons into

2860-429: A wide range of frequencies. To combat the stability problems of the triode as a radio frequency amplifier due to grid-to-plate capacitance, the physicist Walter H. Schottky invented the tetrode or screen grid tube in 1919. He showed that the addition of an electrostatic shield between the control grid and the plate could solve the problem. This design was refined by Hull and Williams. The added grid became known as

2970-445: Is a current . Compare this to the behavior of the bipolar junction transistor , in which the controlling signal is a current and the output is also a current. For vacuum tubes, transconductance or mutual conductance ( g m ) is defined as the change in the plate(anode)/cathode current divided by the corresponding change in the grid to cathode voltage, with a constant plate(anode) to cathode voltage. Typical values of g m for

3080-406: Is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as a thermionic tube or thermionic valve utilizes thermionic emission of electrons from a hot cathode for fundamental electronic functions such as signal amplification and current rectification . Non-thermionic types such as

3190-522: Is amongst his best work." Among the tracks were collaborations with Dick Hyman and Angelo Badalamenti . De Backer began acquiring Ondiolines and having them restored to working condition. In 2016 he assembled a group called the Ondioline Orchestra, with whom he performed on the instrument. The first such concert was a posthumous tribute to Perrey, at National Sawdust in Brooklyn, New York . In

3300-412: Is available as an internal feature of a device that can toggle between STEREO and MONO, for instance many FM radios are capable of toggling between MONO and STEREO in a way where stereo can both MERGE into mono, and then MIRROR between both stereo speakers. This tactic can also be used on other devices, of which computer software and some video games will have a feature that will allow STEREO or MONO for

3410-510: Is controlled by a knee lever . The foremost exponent and popularizer of the instrument was Jean-Jacques Perrey , who performed and recorded with it, composed for it, and served as the instrument's first salesman on behalf of Jenny. Perrey even recorded under the pseudonym "Mr. Ondioline." It is estimated that around 1,200 Ondiolines were constructed between the mid-1940s and the late-1960s, most handmade by Jenny himself. According to Ondioline authority/historian Wally De Backer , "The instrument

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3520-705: Is featured prominently on dozens of early Motown recordings by acts such as the Supremes , the Miracles , the Temptations and the Marvelettes , notably the songs " After All ", " I Want a Guy ", and " (You're My) Dream Come True ", on which it was played by Raynoma Liles Gordy . The first use of the instrument in a film was in 1959, when Perrey played it in the soundtrack of the French film La Vache et le Prisonnier ( The Cow and

3630-550: Is modeled after another early electronic instrument from France, the Ondes Martenot , which was invented in 1928 by Maurice Martenot . Jenny conceived his instrument as a low-cost alternative to the Martenot, which was more sophisticated in construction and more expensive. The Martenot was used mostly in serious music , but Jenny devised the Ondioline for a broader consumer market, including pop music. Joseph A. Paradiso, writing in

3740-439: Is no single standard model of the instrument. Jenny declined to license the instrument for mass production. Perrey claimed that serious works for the Ondioline were composed by Arthur Honegger and Darius Milhaud . According to a 1957 promotional brochure published by Jenny, works had been composed for the instrument by Honneger, Milhaud, Georges Auric , Joseph Kosma , Wanda Landowska , and Marcel Delannoy . A 1958 LP from

3850-469: Is not heated and does not emit electrons. The filament has a dual function: it emits electrons when heated; and, together with the plate, it creates an electric field due to the potential difference between them. Such a tube with only two electrodes is termed a diode , and is used for rectification . Since current can only pass in one direction, such a diode (or rectifier ) will convert alternating current (AC) to pulsating DC. Diodes can therefore be used in

3960-410: Is not important since they are simply re-captured by the plate. But in a tetrode they can be captured by the screen grid since it is also at a positive voltage, robbing them from the plate current and reducing the amplification of the tube. Since secondary electrons can outnumber the primary electrons over a certain range of plate voltages, the plate current can decrease with increasing plate voltage. This

4070-551: Is the Loewe 3NF . This 1920s device has three triodes in a single glass envelope together with all the fixed capacitors and resistors required to make a complete radio receiver. As the Loewe set had only one tube socket, it was able to substantially undercut the competition, since, in Germany, state tax was levied by the number of sockets. However, reliability was compromised, and production costs for

4180-416: Is the dynatron region or tetrode kink and is an example of negative resistance which can itself cause instability. Another undesirable consequence of secondary emission is that screen current is increased, which may cause the screen to exceed its power rating. The otherwise undesirable negative resistance region of the plate characteristic was exploited with the dynatron oscillator circuit to produce

4290-556: The Edison effect , that became well known. Although Edison was aware of the unidirectional property of current flow between the filament and the anode, his interest (and patent ) concentrated on the sensitivity of the anode current to the current through the filament (and thus filament temperature). It was years later that John Ambrose Fleming applied the rectifying property of the Edison effect to detection of radio signals, as an improvement over

4400-661: The plate ( anode ) when the plate was at a positive voltage with respect to the cathode. Electrons could not pass in the reverse direction because the plate was not heated and not capable of thermionic emission of electrons. Fleming filed a patent for these tubes, assigned to the Marconi company, in the UK in November 1904 and this patent was issued in September 1905. Later known as the Fleming valve ,

4510-429: The screen grid or shield grid . The screen grid is operated at a positive voltage significantly less than the plate voltage and it is bypassed to ground with a capacitor of low impedance at the frequencies to be amplified. This arrangement substantially decouples the plate and the control grid , eliminating the need for neutralizing circuitry at medium wave broadcast frequencies. The screen grid also largely reduces

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4620-469: The 6GH8 /ECF82 triode-pentode, quite popular in television receivers. The desire to include even more functions in one envelope resulted in the General Electric Compactron which has 12 pins. A typical example, the 6AG11, contains two triodes and two diodes. Some otherwise conventional tubes do not fall into standard categories; the 6AR8, 6JH8 and 6ME8 have several common grids, followed by

4730-482: The 6SN7 , is a "dual triode" which performs the functions of two triode tubes while taking up half as much space and costing less. The 12AX7 is a dual "high mu" (high voltage gain ) triode in a miniature enclosure, and became widely used in audio signal amplifiers, instruments, and guitar amplifiers . The introduction of the miniature tube base (see below) which can have 9 pins, more than previously available, allowed other multi-section tubes to be introduced, such as

4840-482: The junction field-effect transistor (JFET), although vacuum tubes typically operate at over a hundred volts, unlike most semiconductors in most applications. The 19th century saw increasing research with evacuated tubes, such as the Geissler and Crookes tubes . The many scientists and inventors who experimented with such tubes include Thomas Edison , Eugen Goldstein , Nikola Tesla , and Johann Wilhelm Hittorf . With

4950-464: The magnetic detector . Amplification by vacuum tube became practical only with Lee de Forest 's 1907 invention of the three-terminal " audion " tube, a crude form of what was to become the triode . Being essentially the first electronic amplifier , such tubes were instrumental in long-distance telephony (such as the first coast-to-coast telephone line in the US) and public address systems , and introduced

5060-456: The 1960s it was common for albums to be released as both mono and stereo LPs, occasionally with slight differences between the two (again, detailed information of The Beatles' recordings provides a good example of the differences). This was because many people owned mono record players that were incapable of playing stereo records, as well as the prevalence of AM radio. Because of the limited quantities pressed and alternative mixes of several tracks,

5170-413: The 19th century, telegraph and telephone engineers had recognized the need to extend the distance that signals could be transmitted. In 1906, Robert von Lieben filed for a patent for a cathode-ray tube which used an external magnetic deflection coil and was intended for use as an amplifier in telephony equipment. This von Lieben magnetic deflection tube was not a successful amplifier, however, because of

5280-481: The Audion for demonstration to AT&T's engineering department. Dr. Harold D. Arnold of AT&T recognized that the blue glow was caused by ionized gas. Arnold recommended that AT&T purchase the patent, and AT&T followed his recommendation. Arnold developed high-vacuum tubes which were tested in the summer of 1913 on AT&T's long-distance network. The high-vacuum tubes could operate at high plate voltages without

5390-523: The Beatles , A Hard Day's Night , Beatles for Sale ) were re-released in the CD era as monophonic in recognition of the fact that the source tapes for the earliest recordings were two-track, with vocals on one track and instruments on the other (even though this was only true on the first two albums, while the latter two had been recorded on four-track). This was actually intended to provide flexibility in producing

5500-565: The French Broadcasting System featured six new works composed for the Ondioline: Maurice Bagot's Suite Op.59 (for 3 Ondiolines) ; Gustave Samazeuilh 's Musette (for Ondioline) ; Darius Cittanova's Chants Pour Les Eternites Differentes (for Ondioline) ; Jacques Chailley 's Angelique (for Ondioline) and Ballet Divertissement (for Ondioline) ; and Jacques Castérède 's Eolus (for Ondioline) . The Ondioline's keyboard

5610-404: The Martenot and the Ondioline use vacuum tube circuitry. However, unlike the Martenot, whose oscillator is based on theremin principles (two ultra-high frequencies beating against each other, to produce a third audible frequency), the Ondioline uses a multivibrator oscillator circuit to produce its tone. This gives the Ondioline a tone with richer harmonics than the Martenot. Perrey explained

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5720-534: The Ondes Martenot, which offers only four or five timbres. Because the Ondioline was smaller than a Martenot, it was designed to be portable. Its retail price at the time was US$ 500 (US$ 8,561.42 in 2017 dollars), far less than the cost of the Martenot. In 1951, French composer/singer Charles Trenet heard about Perrey and the Ondioline, and invited him to provide accompaniment on the recording of Trenet's song "L'ame des Poetes" ("The Soul of Poets"). The song became

5830-472: The Ondioline played by Perrey (who had by then moved to New York). The instrument is used in a percussive fashion on the 1964 Terry Stafford hit " Suspicion ." (The player was not identified.) In the late 1960s, rock musician/keyboardist Al Kooper featured the Ondioline on several tracks he recorded with his bands the Blues Project and Blood, Sweat & Tears ; he continued to perform and record with

5940-604: The Prisoner ). The Ondioline was also used in the soundtrack of the 1960 film Spartacus . Jean-Jacques Perrey continued to perform live shows with the Ondioline until his death in 2016; he featured the instrument on his collaborative albums with musician Dana Countryman , The Happy Electropop Music Machine (2006) and Destination Space (2008), both issued on the Oglio label. Shortly after Perrey's death in November 2016, Australian musician Wally De Backer, also known as Gotye , launched

6050-462: The additional controllable electrodes. Other classifications are: Vacuum tubes may have other components and functions than those described above, and are described elsewhere. These include as cathode-ray tubes , which create a beam of electrons for display purposes (such as the television picture tube, in electron microscopy , and in electron beam lithography ); X-ray tubes ; phototubes and photomultipliers (which rely on electron flow through

6160-513: The album The Live Adventures of Mike Bloomfield and Al Kooper (1968); and Kooper's first solo album, I Stand Alone (1969). Tommy James and the Shondells ' 1967 hits " I Think We're Alone Now " and " Mirage " featured Ondioline, played by session keyboardist Artie Butler . Motown Records used an Ondioline as part of their studio setup between 1959 and 1962, where it was mainly used in place of expensive string arrangements. The instrument

6270-400: The allied military by 1916. Historically, vacuum levels in production vacuum tubes typically ranged from 10 μPa down to 10 nPa (8 × 10   Torr down to 8 × 10  Torr). The triode and its derivatives (tetrodes and pentodes) are transconductance devices, in which the controlling signal applied to the grid is a voltage , and the resulting amplified signal appearing at the anode

6380-435: The anode, cathode, and one grid, and so on. The first grid, known as the control grid, (and sometimes other grids) transforms the diode into a voltage-controlled device : the voltage applied to the control grid affects the current between the cathode and the plate. When held negative with respect to the cathode, the control grid creates an electric field that repels electrons emitted by the cathode, thus reducing or even stopping

6490-537: The artifacts of the conversion process. Directors Stanley Kubrick and Woody Allen , among others, preferred to record their films' sound tracks in mono. Monaural LP records were eventually phased out and no longer manufactured after the early 1970s, with a few exceptions. For example, Decca UK had a few double issues until the end of 1970 – the last one being Tom Jones's "I Who Have Nothing"; in Brazil records were released in both mono and stereo as late as 1972. During

6600-479: The base terminals, some tubes had an electrode terminating at a top cap . The principal reason for doing this was to avoid leakage resistance through the tube base, particularly for the high impedance grid input. The bases were commonly made with phenolic insulation which performs poorly as an insulator in humid conditions. Other reasons for using a top cap include improving stability by reducing grid-to-anode capacitance, improved high-frequency performance, keeping

6710-404: The cathode slam into the anode (plate) and heat it; this can occur even in an idle amplifier due to the quiescent current necessary to ensure linearity and low distortion. In a power amplifier, this heating can be considerable and can destroy the tube if driven beyond its safe limits. Since the tube contains a vacuum, the anodes in most small and medium power tubes are cooled by radiation through

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6820-536: The cathode, no direct current could pass from the cathode to the grid. Thus a change of voltage applied to the grid, requiring very little power input to the grid, could make a change in the plate current and could lead to a much larger voltage change at the plate; the result was voltage and power amplification . In 1908, de Forest was granted a patent ( U.S. patent 879,532 ) for such a three-electrode version of his original Audion for use as an electronic amplifier in radio communications. This eventually became known as

6930-419: The cost of the hardware. Some consumer electronics with stereo RCA outputs have a microswitch in the red RCA output (i.e., the right stereo channel) that disables merging of stereo sound into the white (left stereo channel) RCA output. Common devices with this are VCRs , DVD / Blu-ray players , information appliances, set-top boxes , and the like. Video game consoles sometimes have male RCA ends of cables with

7040-400: The current between cathode and anode. As long as the control grid is negative relative to the cathode, essentially no current flows into it, yet a change of several volts on the control grid is sufficient to make a large difference in the plate current, possibly changing the output by hundreds of volts (depending on the circuit). The solid-state device which operates most like the pentode tube is

7150-428: The development of radio , television , radar , sound recording and reproduction , long-distance telephone networks, and analog and early digital computers . Although some applications had used earlier technologies such as the spark gap transmitter for radio or mechanical computers for computing, it was the invention of the thermionic vacuum tube that made these technologies widespread and practical, and created

7260-445: The discipline of electronics . In the 1940s, the invention of semiconductor devices made it possible to produce solid-state devices, which are smaller, safer, cooler, and more efficient, reliable, durable, and economical than thermionic tubes. Beginning in the mid-1960s, thermionic tubes were being replaced by the transistor . However, the cathode-ray tube (CRT) remained the basis for television monitors and oscilloscopes until

7370-546: The early 21st century. Thermionic tubes are still employed in some applications, such as the magnetron used in microwave ovens, certain high-frequency amplifiers , and high end audio amplifiers, which many audio enthusiasts prefer for their "warmer" tube sound , and amplifiers for electric musical instruments such as guitars (for desired effects, such as "overdriving" them to achieve a certain sound or tone). Not all electronic circuit valves or electron tubes are vacuum tubes. Gas-filled tubes are similar devices, but containing

7480-440: The electrical load for a single loudspeaker coil and allow the listener to perceive an "image" of sound in the free space between the speakers. Mirrored mono sound is the opposite of merged stereo, since it can be a case where media with mono sound that stereo playback devices automatically mirror it with are played on both channels of the receiver. It can also mean having a mono input mixed down to stereo amplification circuitry, or

7590-417: The envelope via an airtight seal. Most vacuum tubes have a limited lifetime, due to the filament or heater burning out or other failure modes, so they are made as replaceable units; the electrode leads connect to pins on the tube's base which plug into a tube socket . Tubes were a frequent cause of failure in electronic equipment, and consumers were expected to be able to replace tubes themselves. In addition to

7700-425: The exception of early light bulbs , such tubes were only used in scientific research or as novelties. The groundwork laid by these scientists and inventors, however, was critical to the development of subsequent vacuum tube technology. Although thermionic emission was originally reported in 1873 by Frederick Guthrie , it was Thomas Edison's apparently independent discovery of the phenomenon in 1883, referred to as

7810-419: The filament and cathode. Except for diodes, additional electrodes are positioned between the cathode and the plate (anode). These electrodes are referred to as grids as they are not solid electrodes but sparse elements through which electrons can pass on their way to the plate. The vacuum tube is then known as a triode , tetrode , pentode , etc., depending on the number of grids. A triode has three electrodes:

7920-444: The glass envelope. In some special high power applications, the anode forms part of the vacuum envelope to conduct heat to an external heat sink, usually cooled by a blower, or water-jacket. Klystrons and magnetrons often operate their anodes (called collectors in klystrons) at ground potential to facilitate cooling, particularly with water, without high-voltage insulation. These tubes instead operate with high negative voltages on

8030-411: The influence of the plate voltage on the space charge near the cathode, permitting the tetrode to produce greater voltage gain than the triode in amplifier circuits. While the amplification factors of typical triodes commonly range from below ten to around 100, tetrode amplification factors of 500 are common. Consequently, higher voltage gains from a single tube amplification stage became possible, reducing

8140-473: The instrument and its history. In October 2022, Spitfire Audio released a virtual recreation of the Ondioline, called Electronic Antique, as part of their free LABS plugin. Monaural Monaural sound or monophonic sound (often shortened to mono ) is sound intended to be heard as if it were emanating from one position. This contrasts with stereophonic sound or stereo , which uses two separate audio channels to reproduce sound from two microphones on

8250-547: The instrument in his early solo career. Notable examples are "I Can't Keep from Crying Sometimes" and "Steve's Song" from the 1966 Blues Project album Projections , and "No Time Like the Right Time" ( The Blues Project Live at Town Hall , 1967); "Meagan's Gypsy Eyes" from Blood Sweat & Tears' Child Is Father to the Man (1968); "His Holy Modal Majesty" with Mike Bloomfield on Super Session (1968); "Her Holy Modal Highness" from

8360-426: The instrument's technical advantages. The Ondioline is based on a multivibrator oscillator circuit, producing a pulse-like waveform that is fed through a series of discrete filters. These filters, the switching controls, and the continuous analog controllers are the key to the tremendous variety of timbres obtainable with the Ondioline. When I first saw the instrument, I knew immediately its potential in comparison with

8470-550: The miniature tube version of the " All American Five ". Octodes, such as the 7A8, were rarely used in the United States, but much more common in Europe, particularly in battery operated radios where the lower power consumption was an advantage. To further reduce the cost and complexity of radio equipment, two separate structures (triode and pentode for instance) can be combined in the bulb of a single multisection tube . An early example

8580-434: The model — 10 on earlier models, 17 on later ones) to modify the tones. Used in combination, these switches can create sounds ranging from near-accurate recreations of symphonic instruments (e.g., oboe, French horn) to unique sounds which do not mimic existing instruments. While the Martenot has a ring (or ribbon) controller to control pitch, the Ondioline has a wire strip that when pressed provides percussion effects. Both

8690-510: The monaural versions of these albums are often valued more highly than their stereo LP counterparts in record-collecting circles today. On 9 September 2009, The Beatles re-released a remastered box set of their mono output spanning the Please Please Me album to The Beatles (commonly called "The White Album"). The set, simply called The Beatles in Mono , also includes a two-disc summary of

8800-456: The mono singles, B-sides and EP tracks released throughout their career. Also included were five tracks originally mixed for an unissued mono Yellow Submarine EP . Bob Dylan followed suit on 19 October 2010 with The Original Mono Recordings , a box set featuring the mono releases from Bob Dylan (1962) to John Wesley Harding (1967). On 21 November 2011, The Kinks ' mono recordings were issued as The Kinks in Mono box set, featuring

8910-573: The mono-source material is presented as two identical channels, thus being technically stereo. At various times artists have preferred to work in mono, either in recognition of the technical limitations of the equipment of the era or because of simple preference (this can be seen as analogous to filmmakers working in black and white ). An example is John Mellencamp 's 2010 album No Better Than This , recorded in mono to emulate mid-20th century blues and folk records. Some early recordings such as The Beatles ' first four albums ( Please Please Me , With

9020-431: The number of external pins (leads) often forced the functions to share some of those external connections such as their cathode connections (in addition to the heater connection). The RCA Type 55 is a double diode triode used as a detector, automatic gain control rectifier and audio preamplifier in early AC powered radios. These sets often include the 53 Dual Triode Audio Output. Another early type of multi-section tube,

9130-435: The number of tubes required. Screen grid tubes were marketed by late 1927. However, the useful region of operation of the screen grid tube as an amplifier was limited to plate voltages greater than the screen grid voltage, due to secondary emission from the plate. In any tube, electrons strike the plate with sufficient energy to cause the emission of electrons from its surface. In a triode this secondary emission of electrons

9240-523: The oscillation valve was developed for the purpose of rectifying radio frequency current as the detector component of radio receiver circuits. While offering no advantage over the electrical sensitivity of crystal detectors , the Fleming valve offered advantage, particularly in shipboard use, over the difficulty of adjustment of the crystal detector and the susceptibility of the crystal detector to being dislodged from adjustment by vibration or bumping. In

9350-399: The power used by the deflection coil. Von Lieben would later make refinements to triode vacuum tubes. Lee de Forest is credited with inventing the triode tube in 1907 while experimenting to improve his original (diode) Audion . By placing an additional electrode between the filament ( cathode ) and plate (anode), he discovered the ability of the resulting device to amplify signals. As

9460-458: The practice in recording studios to make separate mixes for mono recordings (rather than folded-down stereo-to-mono), so that the final mono master will avoid the pitfalls of collapsed stereo. In video games, merging stereo to mono sound prevents player from discerning what direction distant SFX are coming from, and reverse stereo has a similar setback too. Having an array of loudspeakers connected to their own amplifier outputs can mitigate issues with

9570-448: The present-day C cell , for which the letter denotes its size and shape). The C battery's positive terminal was connected to the cathode of the tubes (or "ground" in most circuits) and whose negative terminal supplied this bias voltage to the grids of the tubes. Later circuits, after tubes were made with heaters isolated from their cathodes, used cathode biasing , avoiding the need for a separate negative power supply. For cathode biasing,

9680-451: The publication New Music Box , said that both the Martenot and the Ondioline "were truly dexterous performance instruments, as they sported several continuous and discrete controllers that could be articulated by the left hand and knee while the right hand played a melody." The Ondioline is more sonically versatile than the Martenot, which is stylistically limited. The Ondioline has a filter panel, offering from 10 to 17 sliders (depending on

9790-474: The question of thermionic emission and conduction in a vacuum. Consequently, General Electric started producing hard vacuum triodes (which were branded Pliotrons) in 1915. Langmuir patented the hard vacuum triode, but de Forest and AT&T successfully asserted priority and invalidated the patent. Pliotrons were closely followed by the French type ' TM ' and later the English type 'R' which were in widespread use by

9900-528: The releases of the band's albums from Kinks (1964) to Arthur (1969), with three additional CDs of non-album tracks that appeared as singles or EP tracks. When the initial run of the box set sold out, no more were pressed, unlike the Beatles and Dylan sets. Sometimes mono sound or monaural can simply refer to a merged pair of stereo channels - also known as "collapsed stereo" or "folded-down stereo". Over time some devices have used mono sound amplification circuitry with two or more speakers since it can cut

10010-401: The right and left side, which is reproduced with two separate loudspeakers to give a sense of the direction of sound sources. In mono, only one loudspeaker is necessary, but, when played through multiple loudspeakers or headphones, identical audio signals are fed to each speaker, resulting in the perception of one-channel sound "imaging" in one sonic space between the speakers (provided that

10120-416: The right stereo channel in lieu of a "left" one (or vice versa) where both channels are wired to mirror only one. Instances of both "merged stereo" and "mirrored mono" can occur when the stereo channels are merged to a mono system with stereo headphone compatibility or when a mono system has "twin speakers" (or "pseudo-stereo"). Other applications that involve mirrored mono with merged stereo occur when MONO

10230-557: The slight advantage in signal strength and bandwidth the standard affords over a stereophonic signal of the same power. While some experiments were made with stereophonic recording and reproduction from the early days of the phonograph in the late-19th century, monaural was the rule for almost all audio recording until the second half of the 20th century. Monaural sound is normal on: Incompatible standards exist for: Compatible monaural and stereophonic standards exist for: No native monaural standards exist for: In those formats,

10340-588: The soundtrack, in which sometimes this can facilitate MERGING stereo internally to spare one from using a Y adapter with LEFT and RIGHT RCA plugs when using mono equipment, such as guitar amplifiers . Some TV/VCR combo decks on the market had stereo TV functionality with "twin speakers", whereas the VCR feature was only mono, which is typical of "consumer-grade VCRs" from decades ago. Some of these devices even had front RCA inputs for composite video (yellow), and mono audio (white) in which many of these devices didn't even have

10450-437: The speakers are set up in a proper symmetrical critical-listening placement). Monaural recordings, like stereo ones, typically use multiple microphones fed into multiple channels on a recording console, but each channel is " panned " to the center. In the final stage, the various center-panned signal paths are usually mixed down to two identical tracks, which, because they are identical, are perceived upon playback as representing

10560-404: The standard for radiotelephone communications, telephone networks, and audio induction loops for use with hearing aids . FM radio stations broadcast in stereo, while most AM radio stations broadcast in mono. (Although an AM stereo broadcast standard exists, few AM stations are equipped to use it.) A few FM stations—notably talk-radio stations—choose to broadcast in monaural because of

10670-440: The suppressor grid wired internally to the cathode (e.g. EL84/6BQ5) and those with the suppressor grid wired to a separate pin for user access (e.g. 803, 837). An alternative solution for power applications is the beam tetrode or beam power tube , discussed below. Superheterodyne receivers require a local oscillator and mixer , combined in the function of a single pentagrid converter tube. Various alternatives such as using

10780-455: The triode caused early tube audio amplifiers to exhibit harmonic distortion at low volumes. Plotting plate current as a function of applied grid voltage, it was seen that there was a range of grid voltages for which the transfer characteristics were approximately linear. To use this range, a negative bias voltage had to be applied to the grid to position the DC operating point in the linear region. This

10890-407: The triode. De Forest's original device was made with conventional vacuum technology. The vacuum was not a "hard vacuum" but rather left a very small amount of residual gas. The physics behind the device's operation was also not settled. The residual gas would cause a blue glow (visible ionization) when the plate voltage was high (above about 60 volts). In 1912, de Forest and John Stone Stone brought

11000-638: The tube were much greater. In a sense, these were akin to integrated circuits. In the United States, Cleartron briefly produced the "Multivalve" triple triode for use in the Emerson Baby Grand receiver. This Emerson set also has a single tube socket, but because it uses a four-pin base, the additional element connections are made on a "mezzanine" platform at the top of the tube base. By 1940 multisection tubes had become commonplace. There were constraints, however, due to patents and other licensing considerations (see British Valve Association ). Constraints due to

11110-404: The tubes' heaters to be supplied from a common circuit (which can be AC without inducing hum) while allowing the cathodes in different tubes to operate at different voltages. H. J. Round invented the indirectly heated tube around 1913. The filaments require constant and often considerable power, even when amplifying signals at the microwatt level. Power is also dissipated when the electrons from

11220-478: The tubes) without requiring replacement. When triodes were first used in radio transmitters and receivers, it was found that tuned amplification stages had a tendency to oscillate unless their gain was very limited. This was due to the parasitic capacitance between the plate (the amplifier's output) and the control grid (the amplifier's input), known as the Miller capacitance . Eventually the technique of neutralization

11330-406: The vacuum, a process called thermionic emission . This can produce a controllable unidirectional current though the vacuum known as the Edison effect . A second electrode, the anode or plate , will attract those electrons if it is at a more positive voltage. The result is a net flow of electrons from the filament to plate. However, electrons cannot flow in the reverse direction because the plate

11440-421: The voltage applied to the control grid (or simply "grid") was lowered from the cathode's voltage to somewhat more negative voltages, the amount of current from the filament to the plate would be reduced. The negative electrostatic field created by the grid in the vicinity of the cathode would inhibit the passage of emitted electrons and reduce the current to the plate. With the voltage of the grid less than that of

11550-402: Was also offered in 'kit' form, where Jenny recommended purchasing the more complex assemblies – such as the keyboard – as complete units. The schematics were made available for amateur engineers to construct their own custom instruments, and they were encouraged to experiment with the amplifier, tone circuits and cabinetry." Jenny began constructing a first prototype around 1939 (the instrument

11660-449: Was also technical consultant to Edison-Swan . One of Marconi's needs was for improvement of the detector , a device that extracts information from a modulated radio frequency. Marconi had developed a magnetic detector , which was less responsive to natural sources of radio frequency interference than the coherer , but the magnetic detector only provided an audio frequency signal to a telephone receiver. A reliable detector that could drive

11770-469: Was as yet unnamed) while recovering from tuberculosis at a sanatorium in the south of France. The instrument functioned on a valve -based system and contained a built-in amplifier . In 1946, Jenny's working model took first prize in the inventions competition at the Foire de Paris (Paris Fair). By the time Jenny began to manufacture the device commercially in 1947 he had settled on the name "Ondioline." As

11880-405: Was called the idle condition, and the plate current at this point the "idle current". The controlling voltage was superimposed onto the bias voltage, resulting in a linear variation of plate current in response to positive and negative variation of the input voltage around that point. This concept is called grid bias . Many early radio sets had a third battery called the "C battery" (unrelated to

11990-604: Was developed whereby the RF transformer connected to the plate (anode) would include an additional winding in the opposite phase. This winding would be connected back to the grid through a small capacitor, and when properly adjusted would cancel the Miller capacitance. This technique was employed and led to the success of the Neutrodyne radio during the 1920s. However, neutralization required careful adjustment and proved unsatisfactory when used over

12100-401: Was usually connected to the cathode and its negative voltage relative to the anode repelled secondary electrons so that they would be collected by the anode instead of the screen grid. The term pentode means the tube has five electrodes. The pentode was invented in 1926 by Bernard D. H. Tellegen and became generally favored over the simple tetrode. Pentodes are made in two classes: those with

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