![807 807](/uploads/1/1/7/8/117836588/555419693.png)
VU2ATN - Linear Amplifier Using 807 Valves - QRO
When Dr. Ashutosh, VU21F suggested publication of information on my vintage valve type amplifier for NR60, I was hesitant. I guess lot many hams, now-a-days, are not at all aware ofsomething called vacuum tubes &hence there would be no takers for such a recipe. However my choice of such an amplifier aheadof NR60 was based on the following considerations:
Prospective constructors should refer to Radio Handbooks & other standard literature for more information & confidence. The circuit is straight forward &generated from available literature. Here is the circuit diagram with values marked: The transistorized linear driver is expected to swing up to 60 to 70 mA with signal (AF) input. The transistor has to be biased at 20 mA &must be heat-sinked properly. The 25V collector supply need not be switched while going to AM mode. However the 12 V supply must be switched. Similarly for the valve stage, only screen supply shall be disconnected during receive mode. It is needless to say that antenna must be switched between Tx & Rx as shown in the circuit diagram. While dealing with vacuum tubes, please remember all safety aspects &go through very carefully the standard literature. The Power Supply: The power supply for the PA stage is straight forward &as shown in the diagram. The power supply uses a single transformer for I supplying the filament supply, plate &screen voltages &also the I bias supply. The transformer shall not be available off the shelf and it has be to ordered with somebody. However, arrangements can be made for supplying the requisite voltages & current from an alternative source. My set-up is based on a circuit for such a
I hope there will be some takers, HI. Happy construction!. |
807 | |
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Three 807s and an early 6L6, Left, British Emitron brand 807 Right, U.S. Mullard-B.V.A branded 6L6GSecond Left, Canadian Westinghouse brand 807 Second Right, Dutch Philips brand military 807/ATS25 | |
Classification | Beam-power tetrode |
Service | Class-A amplifier, (single-ended) Class-AB amplifier, (push–pull) Class-C amplifier, (radio frequency) |
Cathode | |
Cathode type | Indirectly heated |
Heater voltage | 6.3 |
Heater current | 900 mA |
Anode | |
Max dissipation Watts | 25 W |
Max voltage | 600 V |
Socket connections | |
American 5 Pin, (UY) Pin 1, Heater Top cap, Anode/platePin 2, Screen grid, g2 Pin-3, Control grid, g1 Pin-4, Cathode-beam plates Pin-5, Heater | |
Typical class-A amplifier operation | |
Anode voltage | 300 V, (600 V) |
Anode current | 83 mA, (40-75 mA) |
Screen voltage | 250 V, (300 V) |
Bias voltage | -12.5 V, (-29.5 V) |
Anode resistance | 24 kΩ |
Typical class-C amplifier operation | |
Power output | 24 W, (plate dissipation = 16.5 W max) |
Anode voltage | 475 V |
Anode current | 83 mA |
Screen voltage | 300 V (screen dissipation = 2.5 W max) |
Bias voltage | -50 V |
Typical class-AB amplifier operation (Values are for two tubes) | |
Anode voltage | 400 V (AB1), 600 V (AB2) |
Anode current | 90-119 mA (AB1), 90-240 mA (AB2),(zero to max signal) |
Screen voltage | 300 V (AB1), 300 V (AB2) |
Bias voltage | -45 V (AB1), -25--30 V (AB2) |
References | |
Philips Valve Data Book, Philips Electrical Industries, 69-73 Clarence Street Sydney, Radio Valve Application Division, 1958 Radio Valve Data, Eighth Ed. Iliffe Books Ltd., London, 1966 |
Audio uses[edit]
RF uses[edit]
The class C operational values in the info box at the right are for anode modulated A.M. operation; for CW operation a maximum anode voltage of 600 is permissible, whereby the anode current increases to 100 mA and the anode/plate dissipation rises to 25 watts. The screen voltage is the same, at 300, but its dissipation rises to 3.5 watts.37 watts of R.F. power is produced from 220 mW of drive but only a 50% duty cycle is allowed. The maximum allowable negative control grid, g1 excursion allowable is -200 volts and average control grid current is 5mA in both A.M. and CW modes.[1]Later versions could be used on CW with a supply voltage up to 750 V and a current of 100 mA to produce 50-55 watts of output power.
Differences from 6L6[edit]
Derivatives[edit]
![Diy audio amplifier schematics Diy audio amplifier schematics](/uploads/1/1/7/8/117836588/636447991.gif)
Slang[edit]
See also[edit]
807 Tube Audio Amplifier Schematics
- 6CA7 / EL34
Amplifier Schematics For Free
References[edit]
- ^R.C.A. Air-Cooled Transmitting Tubes, Technical Manual TT3, R.C.A. Manufacturing Company Ltd. Harrison, New Jersey, 1938
- ^'Ham Speak – Know the Lingo'. QRZ.com. Retrieved 9 May 2012.
- ^Midwestern Journal of Language and Folklore. Department of English and Journalism, Indiana State University. 1978.
...amateur slang such as handle (the name of an operator), lid (a poor operator), rig (radio set, equipment), 807 (a can of beer – from resemblance to a now obsolete transmitting tube), and XYL (ex-young lady: wife).