Making certain assumptions about the regulation and line input rating of the transformer, this puts you at nearly 1200V peak at nominal line with no load. The fact that the original circuit used 'very heavy' filter chokes means the transmitter required low ripple, maybe 0.1%. Is this power supply keyed on through the mic? The HV capacitors are going to be a headache, minimizing capacitance means you have to pay attention to regulator bandwidth. A straightforward series regulator using stacked transistors, with the transistor stack shunted by a power resistor stack to supply a sizable portion of the loading, would be one simple way to do it. You would also want foldback current limiting, OV protection for the output, and a turn-on stabilization time of 500ms or less if it is keyed on.
700v regulator circuit help???
Oct 08, 2007
27 Replies
Sounds like a 6146. I once built a transmitter with a pair of 6146B tubes. The power transformer was 400-0-400 with a tuned choke input filter. This put out about 750 V at light load. Power for the 12BY7 driver and the 6146 screens was derived from the transformer center tap. I don't think the 250 ma (something like 6 - 8 Hy)choke weighed as much as 2 lb. One place to look for stuff like that is
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Tam/WB2TT
There's another thing, called a "swinging choke", which apparently is operated right next to its saturation knee - when the current increases, you don't need as much inductance, because you're driving a lower impedance, or something like that.
You can still find definitions on google, but I have no idea if anyone's making new ones these days.
Cheers! Rich
Those using self regulating xformers mechanical inductor or load factor cap should be shot!
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Michael A. Terrell
Central Florida
The guy obviously doesn't have a clue as to what a swinging choke is. Not clear what power factor and self regulating transformers have to do with anything here.
Tam
Yeah, when I saw the swing choke, it just brought back nightmares of issues we had years ago which really has nothing to do with swing chokes. Just a bad memory cropping up. We had to deal with xformers that had gaps in them working with mechanical regulators. I knew at that point some day, that technology was going south.
"I\'m never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5
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