This is for the doubler rectifiers right? Will UF4007 work? (I have a bunch of those).
Yes it will. I just like to overrate parts so I specced a 2 amp part.
Also as a PSA: You don't need to quote if you're replying to the post directly above yours. The redundant data costs the forum money 🙂
Also as a PSA: You don't need to quote if you're replying to the post directly above yours. The redundant data costs the forum money 🙂
Thanks for the high-fives, KodaBMX … you remain my hero of the twisted PP output stage with even more twisted use of pretty-impressively-cheap repurposed toroid-as-power transformers, along with the twisted and cunning topology symmetries. Good stuff.
I too hope you are well.
Did you take a look at the test-box above? Pretty sweet! (though, realistically, probably better implemented in 2021 with the jaw-droppingly-cheap 3½ digit DVM modules you can buy for like $6 a throw. Personally, for the trouble it takes to transcribe a bunch of operating point values to a spreadsheet — by hand of course — compared to just throwing a hundred bucks of Arduino-and-shields at the measurement-and-recording problem, I'd just go for that route.
Then again, I'm a hardware-side programmer by trade.
I also drink gin instead of vodka.
Must be a bad goat.
⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅
I will need a toggle switch to route B+ to the selected plate of a dual tube. I will be around 300Vdc, can I use a switch rated for 250AC?
Or can I use almost any switch as long as I don't hot switch?
Or can I use almost any switch as long as I don't hot switch?
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I've used this relay to switch 300VDC@500mA - it works fine and doesn't arc over on switching. Yes, I know it's only rated for 75VDC. J'men Câlice.
NBC|NBC BM94-12VDC-C|Relays|LCSC
NBC|NBC BM94-12VDC-C|Relays|LCSC
Got this PS today https://www.amazon.com/gp/product/B07MMMNCQL/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Looks like the one your originally linked to. 12Vdc didn't quite get the outputs to the rated values. But 14Vdc did. At 16vdc in I got ~247Vac at the 220 terminal. Is this about what you see with yours?
Looks like the one your originally linked to. 12Vdc didn't quite get the outputs to the rated values. But 14Vdc did. At 16vdc in I got ~247Vac at the 220 terminal. Is this about what you see with yours?
Measuring the AC output probably isn't accurate because it switches at like 37kHz as most meters top out around 1kHz. Output will follow input though - There's no feedback loop.
Looking at the picture, you have a version without DC output.
Rectify the AC to DC with fast diodes like HER108 (1N4007 will fail) and load it with 47k/5W and a cap - that will tell you the AC voltage too (square wave RMS = 0.5 peak so 220VAC turns into 220VDC with a bridge).
Looking at the picture, you have a version without DC output.
Rectify the AC to DC with fast diodes like HER108 (1N4007 will fail) and load it with 47k/5W and a cap - that will tell you the AC voltage too (square wave RMS = 0.5 peak so 220VAC turns into 220VDC with a bridge).
Ok, forgot about the square wave thing. Output freq measures pretty close to 20khz.
I will rig up a doubler and see what I get. I want about 300vdc.
I will rig up a doubler and see what I get. I want about 300vdc.
So using this cheap ac - ac converter https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I rigged up a full-wave doubler and did some load testing. Easily supplied ~170ma at 320v. Don't know how long it would last at that load but I only need about 70ma to test power tubes with my gadget.
I got the DC output version as well and will test that this weekend.
I rigged up a full-wave doubler and did some load testing. Easily supplied ~170ma at 320v. Don't know how long it would last at that load but I only need about 70ma to test power tubes with my gadget.
I got the DC output version as well and will test that this weekend.
Nice. 170mA#320V - enough to run a stereo EL84 amp as I mentioned.
The DC output version is basically the same but switches faster and uses a different coil.
The DC output version is basically the same but switches faster and uses a different coil.
And the DC version is about 1/2 the price which I am trying to figure out why.
So now I have a B+ supply,
6.3 and 12.6 volt supply using a dc buck converter
and a 21 volt supply for my 21GL6 project using a dc boost converter
All running from a computer brick. As you have suggested. Way cool. Thanks for the recommendation.
If I use another brick and isolate the input dc, can I use another DC converter to create a negative supply? I assume I cannot use the same brick because the brick ground is common to the output ground, so I will need to float a second dc source.
So now I have a B+ supply,
6.3 and 12.6 volt supply using a dc buck converter
and a 21 volt supply for my 21GL6 project using a dc boost converter
All running from a computer brick. As you have suggested. Way cool. Thanks for the recommendation.
If I use another brick and isolate the input dc, can I use another DC converter to create a negative supply? I assume I cannot use the same brick because the brick ground is common to the output ground, so I will need to float a second dc source.
You're welcome!
You can indeed use the same brick (if it has the balls) because (at least the DC version) is isolated by the transformer. I use one for bias supply in a lot of my builds, just connect the 12V- like to the (+) of the output and use the (-) as your V- supply. Verify the AC version by looking for continuity from the AC outputs to the DC inputs - they should be open circuit.
As for the price, I find it really depends on where you get them, and COVID has meant that a lot of Chinese sellers won't ship to Canada by post. That means for me the AC version is half the price of the DC one.
If anyone knows where I can get the transformer from the DC version in bulk (or how to wind it - TonyTecson?), I'll make my own.
You can indeed use the same brick (if it has the balls) because (at least the DC version) is isolated by the transformer. I use one for bias supply in a lot of my builds, just connect the 12V- like to the (+) of the output and use the (-) as your V- supply. Verify the AC version by looking for continuity from the AC outputs to the DC inputs - they should be open circuit.
As for the price, I find it really depends on where you get them, and COVID has meant that a lot of Chinese sellers won't ship to Canada by post. That means for me the AC version is half the price of the DC one.
If anyone knows where I can get the transformer from the DC version in bulk (or how to wind it - TonyTecson?), I'll make my own.
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On this one that I have
https://www.amazon.com/Comidox-Conv...1&refRID=9XXDC80N98FKSY8ZFRCG#customerReviews
There is indeed continuity between output ground and input.
https://www.amazon.com/Comidox-Conv...1&refRID=9XXDC80N98FKSY8ZFRCG#customerReviews
There is indeed continuity between output ground and input.
Yes. That one is not isolated unfortunately.
This one is isolated AND dial-a-volt... Step Up High Voltage DC 12V-24V To DC 200V-450V Boost Converter Power Module | eBay
This one is isolated AND dial-a-volt... Step Up High Voltage DC 12V-24V To DC 200V-450V Boost Converter Power Module | eBay
I ordered this one: https://www.amazon.com/gp/product/B01MYLWHZW/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Figure these can share the gnd pin. The single sided one for B+ and get negative bias from the other one going -Vout to gnd.
I am betting the other one can be converted to +/- by adding the other output capacitor, looks like the same board.
Figure these can share the gnd pin. The single sided one for B+ and get negative bias from the other one going -Vout to gnd.
I am betting the other one can be converted to +/- by adding the other output capacitor, looks like the same board.
No, I thought this might be the case, but the transformer has less windings on the SE version (the bobbin in skinnier as in less wire wrapped around it).
They can share the ground pin, but the voltage will be symmetrical. Still, no big deal since the current is so low. You can use a VR or zener and a pot for that side.
They can share the ground pin, but the voltage will be symmetrical. Still, no big deal since the current is so low. You can use a VR or zener and a pot for that side.
I was going to use both boards. The SE for B+ and the V- on the other board for the bias supply.
Drive em both with my 19.5V 7A brick. Use a resistor and pot for the grid bias. Ground the cathode.
Drive em both with my 19.5V 7A brick. Use a resistor and pot for the grid bias. Ground the cathode.
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