What about the amplifiers that modulated the carrier of a 50kW AM transmitter ? 25 kW at less than 3% distortion. Exception to the RCA Ampliphase that didn't have transformers. Flat to
20kH at less than 1% distortion. Like an FM transmitter.Wow, this is a REAL AMPLIFIER !!!!
Oct 14, 2011
36 Replies
Good grief there hasn't been a plate modulated AM transmitter in many decades. That Ampliphase design is from 1935. Think PWM
G=B2
813's are wimpy and ugly. Why not use some real tubes?
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John
Look for the schematics of WLW's 500 KW AM transmitter.
You can't have a sense of humor, if you have no sense.
EL500, EL504 and EL509. They put plenty of oomph with 600 V on anodes, and many could be run as zero-bias triodes by paralleling grid and screen. The grids needed some resistors to ptotect them from excessive dissipation from the drive.
I have also built one audio amplifier with a pair of 813's, but it was for modulating two other 813's.
Tauno Voipio
You'd need a bank of 10 each side to get a kilowatt.
813 is an order of magnitude sturdier than 807. If you do not need the WW2 look of the tubes, 6146 would be a better substitute to 807.
Tauno Voipio
Don't use 813's, if you want some REAL POWER!
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Cheers! Rich
Glass envelope, air cooled, tungsten anode... Amateur.
Try this
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400 watts plate dissipation? What a toy!
John
There are larger bottles in the same line: 4-1000A, or triodes: 3-500Z, 3-1000Z.
Tauno Voipio, OH2UG
Neat. 10 kilowatts for the filament alone.
But audiophools would prefer glass, so they can see the stuff glowing inside.
John
4-400As are especially kewl when the plate glows cherry-red. :-)
Cheers! Rich
For ham radio we've used PL509 because the TV-version was much cheaper and they had that coveted formal 30W plate dissipation rating. It also allowed us to feed five filaments in series. Since that was 40V each we could connect one PL500 (used to regulate the grid 2) in series as well and got an almost perfect match to 230V.
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Regards, Joerg
http://www.analogconsultants.com/
If you can get over 100 A anode current through a vacuum tube, this is quite extraordinary. For a mercury filled tube that is not too spectacular.
Given the rated plate voltage, I think it would be wise to have as much metal as I could fit between the possible X-ray source and my head.
My first novice transmitter used a Horizontal Output tube. (ca. 11960's)
Cheers! Rich
Yeah, and the s/n ratio will be about 2 db. Ever heard of mercury hash?
They do make good ignitrons, however. :-)
Cheers! Rich
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