Pentode Tube

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Pentode Tube

Vintage ~PENTODE 257B ~  High Power Triode Vacuum Tube w/ Padded Cloth *NEW* Vintage ~PENTODE 257B ~ High Power Triode Vacuum Tube w/ Padded Cloth *NEW* Paypal 1 Bid US $5.50 13h 6m
2 Tested Philco Type 41 ST Vacuum Pentode Power/Output Tubes   2 Tested Philco Type 41 ST Vacuum Pentode Power/Output Tubes Paypal 0 Bid US $9.99 17h 1m
5 Type 47 Pentode Amplifier Output Tubes 4 ST 1 Globe Triplett 3444 Tested 5 Type 47 Pentode Amplifier Output Tubes 4 ST 1 Globe Triplett 3444 Tested Paypal 1 Bid US $4.99 17h 44m
5 x CV2105 / DL70 / 6373 MULLARD MILITARY SUB MINI. PENTODE TUBES ~ NOS NIB 5 x CV2105 / DL70 / 6373 MULLARD MILITARY SUB MINI. PENTODE TUBES ~ NOS NIB Paypal 0 Bid US $14.99 19h 27m
4 x 6DX8 / ECL84 AVW RADIOTRON TRIODE PENTODE TUBES * NOS NIB * 4 x 6DX8 / ECL84 AVW RADIOTRON TRIODE PENTODE TUBES * NOS NIB * Paypal 0 Bid US $14.99 19h 27m
5 x CV2299 / DL73  MULLARD MILITARY SUB MINI. PENTODE TUBES ~ NOS NIB 5 x CV2299 / DL73 MULLARD MILITARY SUB MINI. PENTODE TUBES ~ NOS NIB Paypal 0 Bid US $14.99 19h 27m
4 x 7591 JJ TESLA  BEAM PENTODE TUBES * NOS NIB * MATCHED QUAD * 4 x 7591 JJ TESLA BEAM PENTODE TUBES * NOS NIB * MATCHED QUAD * Paypal 1 Bid US $49.99 19h 27m
EF80=6BX6=Z719=Z152=8D6=64SPT WF PENTODE VACUUM TUBE NOS Old stock VINTAGE QTY=1 EF80=6BX6=Z719=Z152=8D6=64SPT WF PENTODE VACUUM TUBE NOS Old stock VINTAGE QTY=1 Paypal 0 Bid US $3.99 1d 3h 38m
EL81=6CJ6 TESLA OUTPUT PENTODE TUBE NOS OLD STOCK VINTAGE QTY=3 EL81=6CJ6 TESLA OUTPUT PENTODE TUBE NOS OLD STOCK VINTAGE QTY=3 Paypal 0 Bid US $4.99 1d 3h 39m
6AF9 = EFL200 = 6Y9 Double Pentode Tubes. Lot of 4 6AF9 = EFL200 = 6Y9 Double Pentode Tubes. Lot of 4 Paypal US $7.95 1d 5h 55m
^ NOS NIB Tung-Sol type 47 power pentode radio tube,original box,tested great! ^ NOS NIB Tung-Sol type 47 power pentode radio tube,original box,tested great! Paypal 1 Bid US $9.99 1d 9h 46m
337A tube Western Electric NOS original box audio pentode 337A tube Western Electric NOS original box audio pentode Paypal 0 Bid US $69.99 1d 10h 30m
 GU50  tube Audiophile Pentode Lot of 4 NOS GU50 tube Audiophile Pentode Lot of 4 NOS Paypal 0 Bid US $12.00 1d 11h 5m
5  RCA  6GH8A  Pentode / Triode Tubes ~ NOS  NIB 5 RCA 6GH8A Pentode / Triode Tubes ~ NOS NIB Paypal US $19.95 1d 15h 55m
1 Tungsram E83F / 6689 Pentode Tubes for Audio ~ NIB 1 Tungsram E83F / 6689 Pentode Tubes for Audio ~ NIB Paypal 0 Bid US $7.95 1d 15h 55m
1 Amperex / Mullard 7643 E80CF Triode Pentode Tube  NOS 1 Amperex / Mullard 7643 E80CF Triode Pentode Tube NOS Paypal US $79.95 1d 15h 55m
1 Westinghouse 7734 6GE8 Triode Pentode Tube ~ NOS  NIB 1 Westinghouse 7734 6GE8 Triode Pentode Tube ~ NOS NIB Paypal US $29.95 1d 15h 55m
Four Type 802 Transmitting Pentode Tubes / Class A amp  .. RCA, GE, RCA/DeForest Four Type 802 Transmitting Pentode Tubes / Class A amp .. RCA, GE, RCA/DeForest Paypal 0 Bid US $9.99 1d 18h 39m
USED GE 6K6GT Power Amplifier Pentode Electron/Vacuum Tube #3641110 USED GE 6K6GT Power Amplifier Pentode Electron/Vacuum Tube #3641110 Paypal US $5.50 2d 6h 46m
USED FMCo F.M.Co 6SK7GT Remote Cut-Off RF Pentode Rectifier Tube #3641112 USED FMCo F.M.Co 6SK7GT Remote Cut-Off RF Pentode Rectifier Tube #3641112 Paypal US $5.50 2d 6h 47m
USED (Looks NOS) RCA 6AC7/1852 Metal Sharp Cut-off Pentode Vacuum Tube #0571230 USED (Looks NOS) RCA 6AC7/1852 Metal Sharp Cut-off Pentode Vacuum Tube #0571230 Paypal US $5.50 2d 6h 49m
USED Sylvania 6AU6 Sharp Cutoff RF Pentode Electron/Vacuum Tube #0571235 USED Sylvania 6AU6 Sharp Cutoff RF Pentode Electron/Vacuum Tube #0571235 Paypal US $5.50 2d 6h 49m
USED Sylvania 6BA6 Remote Cutoff RF Pentode Electron/Vacuum Tube #0571226 USED Sylvania 6BA6 Remote Cutoff RF Pentode Electron/Vacuum Tube #0571226 Paypal US $5.50 2d 6h 50m
USED GE General Electric 6AU6 Sharp-Cutoff RF Pentode Tube #0571221 USED GE General Electric 6AU6 Sharp-Cutoff RF Pentode Tube #0571221 Paypal US $5.50 2d 6h 51m
TWO USED 1950s MULLARD EL37 PENTODE AMPLIFIER Vacuum Tubes. TWO USED 1950s MULLARD EL37 PENTODE AMPLIFIER Vacuum Tubes. Paypal 5 Bids US $51.00 2d 8h 44m
3AU6 , GE PENTODE TESTED TUBE, sweep electron tubes 3AU6 , GE PENTODE TESTED TUBE, sweep electron tubes Paypal US $1.09 2d 8h 50m
FOUR (4) 1N5GT vacuum tubes, battery, RF, pentode, ham, radio, valves FOUR (4) 1N5GT vacuum tubes, battery, RF, pentode, ham, radio, valves Paypal 0 Bid US $10.00 2d 9h 55m
BULK  50x  2K2M Soviet HF Pentode TUBE NIB 50's   BULK BULK 50x 2K2M Soviet HF Pentode TUBE NIB 50's BULK Paypal 0 Bid US $74.99 2d 12h 45m
Raytheon JAN 6088 Submini Pentode tube - NIB - SET OF FOUR!!!!! Raytheon JAN 6088 Submini Pentode tube - NIB - SET OF FOUR!!!!! Paypal 0 Bid US $15.95 2d 13h 47m
2 NOS 1960's RCA 1U5 Vacuum Tubes Pentode/Diodes for Zenith TransOceanic Radios 2 NOS 1960's RCA 1U5 Vacuum Tubes Pentode/Diodes for Zenith TransOceanic Radios Paypal 0 Bid US $9.99 2d 19h 41m
GU 50 -  LS50 - GU-50  Pentode Lot of 50 tubes USSR GU 50 - LS50 - GU-50 Pentode Lot of 50 tubes USSR Paypal US $199.99 9d 23h 17m
6J1P-EV / EF95 / 6F32  Pentode Tubes Lot  10 NEW BOXED 6J1P-EV / EF95 / 6F32 Pentode Tubes Lot 10 NEW BOXED Paypal US $9.90 23d 13h 37m
x100   1J24B / 1Zh24B Russian miniature pentode Tubes x100 1J24B / 1Zh24B Russian miniature pentode Tubes Paypal US $79.95 28d 1h 12m
1J37B Russian miniature pentode Tubes NOS  Lot of 100 1J37B Russian miniature pentode Tubes NOS Lot of 100 Paypal US $112.00 17d 18h 16m
CRC-803 /VT106 Power Pentode tube CRC-803 /VT106 Power Pentode tube Paypal 0 Bid US $5.00 3d 12h 49m
EX Sylvania 6F6 6F6G Power Pentode Audio Amplifier Hifi Stereo Vacuum tube EX Sylvania 6F6 6F6G Power Pentode Audio Amplifier Hifi Stereo Vacuum tube Paypal US $14.99 3d 14h 9m
Two 6D6  Sylvania Receiving Pentode Amplifier Vacuum Tubes Two 6D6 Sylvania Receiving Pentode Amplifier Vacuum Tubes Paypal 0 Bid US $3.00 3d 15h 48m
6P15P-EV  EL83  SV83  Pentode TUBES LOT OF 50  NEW!!! 6P15P-EV EL83 SV83 Pentode TUBES LOT OF 50 NEW!!! Paypal US $129.00 14d 6h 53m
1J37B Vintage Soviet miniature pentode NOS TUBE QTY=15 1J37B Vintage Soviet miniature pentode NOS TUBE QTY=15 Paypal 0 Bid US $8.88 3d 17h 13m
2x MATCHED EL861 RFT Amplifier Pentode Tubes  E81L Gold 2x MATCHED EL861 RFT Amplifier Pentode Tubes E81L Gold Paypal 0 Bid US $9.99 3d 17h 13m
10x  6P18P Soviet 70's CCCP Audiophile Audio Pentode Output TUBE / EL82 10x 6P18P Soviet 70's CCCP Audiophile Audio Pentode Output TUBE / EL82 Paypal 0 Bid US $9.99 3d 17h 22m
5 NEW IN BOX 6AG5 / EF96 RF PENTODE VALVES / TUBES 5 NEW IN BOX 6AG5 / EF96 RF PENTODE VALVES / TUBES Paypal US $9.95 3d 17h 23m
4 NOS/NIB DUMONT 6HB6 Audio Amplifer HiFi Stereo Power Pentode Vacuum tubes 4 NOS/NIB DUMONT 6HB6 Audio Amplifer HiFi Stereo Power Pentode Vacuum tubes Paypal US $14.99 3d 17h 48m
1P24B-V Russian miniature pentode Tubes New Lot 100 1P24B-V Russian miniature pentode Tubes New Lot 100 Paypal US $120.00 4d 9h 10m
EL12n RFT NOS Vacuum Pentode Power Output TUBE / EL12 EL12n RFT NOS Vacuum Pentode Power Output TUBE / EL12 Paypal US $24.99 25d 1h 11m
6J8 = 6SJ7 HF Pentode Tube, METAL ENVELOPE, Novosibirsk, NOS, OTK, 1973, 16pc 6J8 = 6SJ7 HF Pentode Tube, METAL ENVELOPE, Novosibirsk, NOS, OTK, 1973, 16pc Paypal US $55.99 27d 1h 41m
NOS Military GK-71 250W directly heated Power Pentode for tube amplifier NOS Military GK-71 250W directly heated Power Pentode for tube amplifier Paypal US $19.50 21d 21h 2m
x8  6P30B Soviet miniature Output Pentode Tubes NOS x8 6P30B Soviet miniature Output Pentode Tubes NOS Paypal US $12.95 23d 12h 29m
GU-50 / GU50 / LS50 Russian Pentode Tubes Lot of 16 NEW GU-50 / GU50 / LS50 Russian Pentode Tubes Lot of 16 NEW Paypal US $56.00 20d 7h 48m
AUDIO PENTODE TUBE EF86 6267 AUDIO PENTODE TUBE EF86 6267 Paypal US $10.00 28d 33m
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Hammond 1640SEA Single Ended Hammond 1640SEA Single Ended "Classic", Ultra Linear Class-A Tube Output Transformer
Sale Price: $160.00

The Hammond 1640SEA is designed for single-ended tube output circuits. Includes a 40% screen grid tap for Ultra-Linear operation. Black matte finish. Audio watts: 30; Primary impedance: 1,250.

Hammond 1627SEA Output Transformer Hammond 1627SEA Output Transformer
Sale Price: $167.95

The SE series is designed for single-ended tube output circuits. Each unit includes a 40% screen grid tap for Ultra-Linear operation. Black matte finish. Audio Watts: 25, Primary Impedance: 2,500. Suggested tube type: Triodes - 2A3, 6A3, 6B4G, 300B. Pentodes - 6CA7, 6L6, 807, 5881, 6550, parallel 6AQ5, 6V6, EL84.

Power Vacuum Tubes Handbook, Third Edition (Electronics Handbook Series) Power Vacuum Tubes Handbook, Third Edition (Electronics Handbook Series)
List Price: $149.95
Sale Price: $128.67

Providing examples of applications, Power Vacuum Tubes Handbook, Third Edition examines the underlying technology of each type of power vacuum tube device in common use today. The author presents basic principles, reports on new development efforts, and discusses implementation and maintenance considerations. Supporting mathematical equations and extensive technical illustrations and schematic diagrams help readers understand the material.Translate Principles into Specific Applications This one-stop reference is a hands-on guide for engineering personnel involved in the design, specification, installation, and maintenance of high-power equipment utilizing vacuum tubes. It offers a comprehensive look at the important area of high-frequency/high-power applications of microwave power devices, making it possible for general principles to be translated into specific applications. Coverage includes power grid tubes—triodes, tetrodes, and pentodes—as well as microwave power tubes such as klystrons, traveling wave tubes, gyrotrons, and other high-frequency devices. These vacuum tubes are used in applications from radio broadcasting to television, radar, satellite communications, and more. Explore a Wide Variety of Methods in Power Vacuum Tube Design This third edition includes updates on vacuum tube technology, devices, applications, design methods, and modulation methods. It also expands its scope to cover properties of materials and RF system maintenance and troubleshooting. Explaining difficult concepts and processes clearly, this handbook guides readers in the design and selection of a power vacuum tube-based system. What’s New in This Edition Includes two new chapters on properties of materials and RF system maintenance and troubleshooting Contains updates and additions in most chapters Identifies key applications for commercial and scientific research Examines the frontiers of materials science directly impacting construction, reliability, and performance Reviews methods of power tube design for more efficient, longer-lasting tubes Features updated illustrations throughout to clarify and explain fundamental principles and implementation considerations

Circuit Analysis of a Legendary Tube Amplifier: The Fender Bassman 5F6-A, Second Edition Circuit Analysis of a Legendary Tube Amplifier: The Fender Bassman 5F6-A, Second Edition

This book moves beyond general principles of tube amplifier design to carry out an intense examination of one of the most famous circuits of the rock era. The book begins with the 5F6A's relatively simple triode preamps (bypassed cathode resistor, unbypassed cathode resistor, and cathode follower) and then progresses through the mathematically challenging tone stack, long-tailed-pair phase splitter, and push-pull power amp. Every formula for every tube is derived in all its gory detail. The author's methods include the classic load lines and composite characteristic curves of Frederick Terman and the Radiotron Designer's Handbook as well as more modern techniques like linear regression and the Discrete Fourier Transform. Special attention is paid to quantifying the push-pull amplifier's nonlinear response and to analyzing power supply voltage sag as it reacts over time. This expanded, second edition includes an enlarged, fold-out schematic of the Bassman and a new chapter on the Marshall JTM45, which is almost a direct copy of the 5F6-A. The Bassman 5F6A circuit has inspired guitar amplifier designs for over four decades, so sharpen your pencil, fire up your calculator, and find out what makes this amp rock!

Vacuum Tube Circuit Design: Guitar Amplifier Preamps Vacuum Tube Circuit Design: Guitar Amplifier Preamps

An in-depth understanding of preamp circuits is essential to creating a guitar amplifier design that stands out from the crowd. It is here that the designer gets a first crack at setting the amp's gain, frequency response, and distortion limits. Written for electronic engineers and professional amp builders, Guitar Amplifier Preamps moves beyond simplistic advice and cookbook solutions to present a complete guide to the theory and operation of triode and pentode voltage amplification. From the guitar pickup to the second stage grid, every aspect of circuit design is rigorously explained and thoroughly explored using real-world examples from Ampeg, Fender, Gibson, Laney, Marshall, Matchless, Orange, and Vox. The frequency shaping and distortion created in the first amplification stage affect the entire signal chain. Guitar Amplifier Preamps helps you get the most out of it.

AYON AUDIO ORION I TUBE AMPLIFIER AYON AUDIO ORION I TUBE AMPLIFIER
List Price: $3,199.00
Sale Price: $3,200.00

USA Tube Audio - Since 1976 Please call 1-800-676-1085 Sales Ext 2 - USA + Canada 1-323-657-5993 International 52-55-8525-6102 Mexico www.usatubeaudio.com Ayon Audio - Orion Integrated Amplifier 3 year warranty! HOOK UP ANY USB DEVICE TO THE NEW ORION VIA USB INPUT ! THE NEW - NEW ORION COMES STOCK WITH THE GOLD LION GENALEX KT-88 TUBES - THE BEST KT-88'S ON THE PLANET! SIGNAL TUBES ARE NOS TUBES - RCA - GE - RAYTHEON AYON AUDIO - ORION I INTEGRATED AMPLIFIER "SILKY SMOOTH" THREE DIMENSIONAL, TRANSPARENT, TIGHT BASS, WARM FLUID MIDS, SUPER SMOOTH HIGHS BEST OF SHOW! AYON AUDIO "BEST OF SHOW" WINNER AT RMAF HIGH PERFORMANCE AUDIO SHOW IN DENVER COLORADO CES 2010 "BEST OF SHOW" AWARD! SALON SON IMAGE SHOW MONTREAL CANADA "BEST SOUND OF SHOW" AWARD! THE NEW AYON AUDIO ORION I INTEGRATED AMPLIFIER IS REMARKABLE REVIEW WINNER !!! See the Excellent Review on the Ayon Audio Spirit at Positive FeedBack ..... New Issue!! http://www.positive-feedback.com/Issue37/ayon_spirit.htm "The Ayon Audio Spirit integrated thrilled me" "It is beautifully built and beautifully engineered" "The Spirit conveyed the ambience of each CD or LP with impressive versatility and range" "It sounded superb, but in triode it was uncanny: the reach-out-and-touch-it quality" "Percussion was incredible-the most strikingly real reproduction I've heard in my home" "The finest amplifier I've heard in my system !" Tom Campbell - POSTIVE FEEDBACK ======================= Granting Audiophiles around the globe, balance, clarity, perspective, dynamics, bloom, decay...The entire musical message for over 20 years. Ayon Audio engineers are established leaders in their respective fields of high-end audio expertise. Our range of activities covers the development of high performance vacuum triode tubes, the design of sonically superior tube preamps, tube power amplifiers, tube CD Players, state of the art cables and advanced technology speaker systems.

Blue Microphones Bottle Tube Microphone System with B6 Blue Microphones Bottle Tube Microphone System with B6
List Price: $5,999.00
Sale Price: $5,999.00

Tube mic with custom transformer and interchangeable capsule system includes B6 capsule, shockmount, power supply, multi-pin cable and flight case


Pentode Tube

Heat generation and transfer of Vacuum tube

A considerable amount of heat is produced when tubes operate, both from the filament (heater) but also from the stream of electrons bombarding the plate. The requirements for heat removal can significantly change the appearance of high-power vacuum tubes. Although the miniature tube style became predominant in consumer equipment, high power audio amplifiers and rectifiers would still require the larger "octal" style of enclosure. Transmitting tubes could be much larger still. where to buy cheap LED Strip? Lightereryday is a good choice.

Most tubes produce heat from two sources during operation. The first source is the filament or heater. Some tubes contain a directly heated cathode. This is a filament similar to an incandescent electric lamp; some types glow brightly like a lamp, but most glow a dim orange-red. The "bright emitter" types possess a tungsten filament alloyed with 1–3 % thorium which reduces the work function of the metal, giving it the ability to emit sufficient electrons at about 2000 degrees Celsius. The "dull emitter" types also possess a tungsten filament but it is coated in a mixture of calcium, strontium and barium oxides, which emit electrons easily at much lower temperatures due to a monolayer of mixed alkali earth metals coating the tungsten; these only reach 800–1000 degrees Celsius.

The second form of cathode is the indirectly heated form which usually consists of a nickel cylinder, coated on the outside with the same strontium, calcium, barium oxide mix used in the "dull emitter" directly heated types. Inside the cylinder is a tungsten filament to heat it. This filament is usually uncoiled and coated in a layer of alumina (aluminium oxide) in order to insulate it electrically from the actual cathode. This form of construction allows for a much greater electron emitting area and allows the cathode to be held at a potential difference, typically 150 volts more positive than the heater or 50 volts more negative than the heater. For small-signal tubes such as used in radio receivers, heaters consume between 50 mW and 5 watts, (directly heated), or between 500 mW and 8 watts for indirectly heated types. Thus even a small signal amplifier might consume a watt of power just to warm its heater, compared to the milliwatts (or less) that a modern semiconductor amplifier would require for the same function. Even in power amplifiers the filament power may be responsible for an appreciable reduction in efficiency.

The second source of heat is generated at the plate (anode), as electrons accelerated by its high voltage strike it, depositing their kinetic energy there and raising its temperature. In tubes used in power amplifiers or transmitter output stages, this source of heat will far exceed the power due to the cathode heater. The plates of improperly operated or overloaded beam power tubes can sometimes become visibly red hot; this should never occur under normal operation of consumer electronics and is a precursor to tube failure.

Heat escapes the device by black body radiation from the anode (plate) as infrared radiation. Convection is not possible in most tubes since the anode is surrounded by vacuum. Considerations of heat removal can affect the overall appearance of some tubes. The anode is often treated to make its surface less shiny and darker in the infrared (see black body radiator). The screen grid may also generate considerable heat, which is radiated toward the plate which must reradiate that additional heat along with the heat it generates itself. Limits to screen grid dissipation, in addition to plate dissipation, are listed for power devices. If these are exceeded then tube failure is likely. recommend directory:Waterproof IP68 Aluminum Shell SMD 5050 LED Light Bar.

Tubes used as power amplifier stages for radio transmitters may have additional heat exchangers, cooling fans, radiator fins, or other measures to improve heat transfer at the anode (plate). High power transmitting tubes may have the surface of their anodes external to the tube, allowing for water cooling or evaporative cooling. Such a water cooling system must be electrically isolated to withstand the high voltage present on the anode.

Tubes which generate rather little heat, such as the 1.4 volt filament directly heated tubes designed for use in battery powered equipment, often have shiny metal anodes. 1T4, 1R5 and 1A7 are examples. Gas filled tubes such as thyratrons may also use a shiny metal anode since the gas present inside the tube allows for convection of heat from the anode to the glass enclosure.

The outer electrode in most tubes is the anode (plate). Some small signal types, such as sharp and remote cut-off R.F. and A.F. pentodes and some pentagrid converters have a shield fitted around all the electrodes enclosing the anode. This shield is sometimes a solid metal sheet, treated to make it dull and gray so that it can itself reradiate heat generated from within. Sometimes it is fabricated from expanded metal mesh, acting as a Faraday cage but allowing sufficient infrared radiation from the anode to escape. Types 6BX6/EF80 and 6BK8/EF86 are typical examples of this shielded type using expanded mesh. Types 6AU6/EF94 and 6BE6/EK90 are examples which use a gray sheet metal cylindrical shield.

Vacuum tubes, which could be used for switching, made electronic computing possible for the first time, but the cost and relatively short mean time between failure of tubes were limiting factors. "The common wisdom was that valves—which, like light bulbs, contained a hot glowing filament—could never be used satisfactorily in large numbers, for they were unreliable, and in a large installation too many would fail in too short a time". Tommy Flowers, who later designed Colossus, "discovered that, so long as valves were switched on and left on, they could operate reliably for very long periods, especially if their ‘heaters' were run on a reduced current". In 1934 Flowers built a successful experimental installation using over 3,000 tubes in small independent modules; it was accepted by the Post Office (who operated telephone exchanges). Flowers was also a pioneer of using tubes as very fast (compared to electromechanical devices) electronic switches. Later work confirmed that tube unreliability was not as serious an issue as generally believed; the 1946 ENIAC, with over 17,000 tubes, had a tube failure (which took 15 minutes to locate) on average every two days. During the second world war Colossus was instrumental in breaking German codes. After the war development continued, with tube-based computers including military computers ENIAC and Whirlwind, the Ferranti Mark 1 (the first commercially available electronic computer), and UNIVAC I, also available commercially.

There is a group of people rebuilding old computers, many solid-state, but some with tubes. Their website includes discussion of circuits, various tubes built specifically for computer use (ECC91 for general logic use, E90CC and E92CC for computer use), and other information. A Colossus has been rebuilt; the only tube computer being restored as of 2011 was the very reliable but very slow Harwell WITCH.

Flowers's Colossus and its successor Colossus Mk2 were built by the British during World War II to substantially speed up the task of breaking the German high level Lorenz encryption. Using about 1,500 vacuum tubes (2,400 for Mk2), Colossus replaced an earlier machine based on relay and switch logic (the Heath Robinson). Colossus was able to break in a matter of hours messages that had previously taken several weeks; it was also much more reliable. Colossus was the first use of vacuum tubes working in concert on such a large scale for a single machine (the 1934 installation used many small modules).

Once Colossus was built and installed, it ran continuously, powered by dual redundant diesel generators, the wartime mains supply being considered too unreliable. The only time it was switched off was for conversion to Mk2, with the addition of more tubes. Another nine Colossus Mk2s were built, and all ten machines were surprisingly reliable. The ten machines drew 15 kilowatts of power each continuously, largely for the tube heaters.

A working Colossus has been rebuilt, and was switched on in 1996, followed by a Mk2 in 2004; a German code was (belatedly) deciphered in 2007. recommend directory: 3528 SMD Flexible Strip with waterproof 5 Meter 300 LEDS.

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Valve (tube) radio question .....?

Suppose you have a standard four-plus-rectifier superhet, and the capacitor decoupling the supply to the frequency changer has gone very low-value. Now, as the resistance of the output pentode is varying in sympathy with the audio signal, this ought to superimpose an inverted copy of the audio on the supply to the local oscillator and so modulate the L.O. output. So would the set effectively be retransmitting on its own L.O. frequency? If the set had a P/U input and you fed an audio signal into here, would you get a (short range) TX?

Came by your question by chance, the short answer is no...
I can see your line of reasoning, but from what you've written I can tell that you don't know enough yet to understand an explanation of why not.

Thanks for visiting!

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