Great, thanks a lot. I had already checked some lambda schematics but found they also violate max B+ voltages of the tubes. The kepco 605 I could find neither the manual nor the schematic, but all the information I needed to know was in this page:
Kepco 605 Regulated Power Supply
I quote: "To ease the requirement of regulating up to half an amp at the lower voltage points with a top end of 600 volts DC, the main transformer supplying the regulated B+ is controlled by a variac. The variac shaft has an insulated coupling to a flexible shaft that turns a potentiometer voltage control enabling a single control for regulated voltage from zero to 600."
In essence it is the same principle as the thyratron idea but with a variac, loosely regulating the rectified voltage simultaneously so the series tubes can always be kept dropping low volts allowing for high current at all voltage settings. It is tempting to think I could have a 0-600V (or more...) @330ma power supply in this manner
It is tempting to think I could have a 0-600V (or more...) @330ma power supply in this manner
So a modern boat anchor is on the way?
A pentode power tube seems like a good choice for the pass device, since you can use the screen grid itself to help limit current in an overload situation, such as accidentally shorting the output leads (this seems like a "must solve" scenario for a bench power supply). That's how the IP-17 did it, at least partially.
I had suggested a ГУ-50 (GU-50), which the OP thought was "overkill", so I'm guessing a 6HV5A (which is as big or bigger) might get the same reception.
Anyway, I still say that'd be a good way to go for all-tube — they can be had for $5 or $10, last forever, and handle up to 1000V — (according to his original post, he needs at least 800V, and it's good to have some margin.
I dunno; maybe it's the 12.6V heater?)
worst case for psu is small Uout hi Iout, you will melt the plates
why not a crude regulator with thyratrons, to keep same voltage on those series tubes.. + some opto, bjts, and maybe traco dc/dc for floating biases ...
less heat also
thyratron works like adjustable bias breakdown thyristor, somewhat.
why not a crude regulator with thyratrons, to keep same voltage on those series tubes.. + some opto, bjts, and maybe traco dc/dc for floating biases ...
less heat also
thyratron works like adjustable bias breakdown thyristor, somewhat.
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From the OP:
...I´d like to keep it all tube despite knowing how much easier it would be with SS electronics, like a challenge lets say
I´m leaning towards the thyratron rectifier alternative given the advantages it provides, only problem is to find the right tube.
The 6012 can be had reasonably cheap but its max inverse plate voltage is 1300V which wouldn´t really get me to a high enough DC output unless I push is beyond that (Would it be safe?). The perfect tube would seem to be the 5557 (or FG17) but it is a lot more expensive and harder to find. Searching for other options I came across the 7410 which is reasonably cheap, but I cant find its datasheet, anyone have it? (best I could find is that it is like a 3c23 which also doesn´t fit the bill)
If someone could point other options that would be really helpful, looking for PIV of ~2kv or more, average current rating of ~200ma or more and preferably octal base although 4 pin is no problem too.
The 6012 can be had reasonably cheap but its max inverse plate voltage is 1300V which wouldn´t really get me to a high enough DC output unless I push is beyond that (Would it be safe?). The perfect tube would seem to be the 5557 (or FG17) but it is a lot more expensive and harder to find. Searching for other options I came across the 7410 which is reasonably cheap, but I cant find its datasheet, anyone have it? (best I could find is that it is like a 3c23 which also doesn´t fit the bill)
If someone could point other options that would be really helpful, looking for PIV of ~2kv or more, average current rating of ~200ma or more and preferably octal base although 4 pin is no problem too.
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Thanks! I´ll be on the lookout for a cheap variac, and if I find one make something similar (hopefully simpler) than the Kepco.
Yeah, unfortunately. It has to do with the gas used to fill the tube, the 5557 datasheet states it is only mercury filled to be used at high voltages so I figured I´d look for other mercury thyratrons.
That seems to confirm that the 5557 is the best candidate, all other options are a step above powerwise (50 watts for each heater is too much). All the same it occured to me to use a voltage doubler which would allow me to use the 6012 tube, although I´ll have to rethink the grid-control circuit.
Said it a couple times in the thread, just want to use tubes because I like them. A lot of what we build can be done more easily with ss, yet people still want to go vacuum state because they like to. If we wanted cheap, tube audio wouldn´t be the best hobby now, would it?
Makes sense, thanksSaid it a couple times in the thread, just want to use tubes because I like them. A lot of what we build can be done more easily with ss, yet people still want to go vacuum state because they like to. If we wanted cheap, tube audio wouldn´t be the best hobby now, would it?
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Hello,
Would you care to share the schematic? I have an ARC-5 transmitter that needs 500v B+ and around 250v for the screens. It needs a well regulated supply so the CW tone has no chirp, and no TVI is generated.
Robert
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