I built a Power Supply that has stabilized adjustable voltage from 240-500V with up to 500MA and it has ripple less than 1mv over the whole range that is also placed above 22khz range. The power is so clean the amp it drives don´t need any power filters and the voltage you pick is stable within less than 1 volt even if you have big power swing in the tubes. so basically you pick a voltage and no matter what the amp or mains does your selected voltage stays the exact same even if your amp pulls heavy varying load from it. A DMM cannot measure any ripple at all, it is only with a sensitive scope you can measure a fraction of a millivolt of ripple above 22khz on this supply. but with that said if you drop my power supply on your foot you never walk on it again
Thanks for the excellent video. Is the 12V zener diode used to bias Vgs of the MOSFET to turn it on? So does this mean that there is 12V drop between the drain and source of the MOSFET? And you would use this to calculate the power dissipation of the MOSFET, and the heatsink required, correct? What is your thought on putting a LR8 voltage regulator from the node between R524 & C503 to the node below R1? Thanks again. I'm having a difficult time finding LTSPICE model for LR8 so I don't know how to simulate it.
The Zener is there to protect the gate from over-voltage. Very common in switching supplies but probably not necessary in this application and could be left out.
Saludos. Excelente Proyecto. Estoy haciendo un probador de tubos y quisiera construir este circuito para el modulo de HV. Hiciste alguna modificacion final?
@@myalbatech The schematic I saw in the video looked to be a single stage, rectified RC filter to a saturated FET capacitance multiplier. Which is basically what you described. But you mention adding additional cap multiplier stages in series. Which would normally result in the full voltage being seen on both legs of the second and subsequent cap multiplier stages. Where as you look to be pulling multiple voltages from the voltage dividers in the tails of the FETs. Which I've only seen possible if they are connected in parallel. Otherwise the FET doesn't saturate, limiting current. Or are the voltages so high that it doesn't matter and the FET stays saturated regardless? So I'm wondering how exactly you coupled the multiple stages together. Which isn't in the schematic I saw at the beginning of the video.
@@myalbatech Interesting. Cascaded, with proper component selection, it should also be possible to achieve substantial voltage regulation. At least at much lower voltages. Ive never played around with that outside of sub 3 volt logic circuits. At these voltages, and with tubes, I'd normally be looking at shunt regulation. But this should make for some fun experimenting in a 2A3 parallel feed SET circuit. Should keep me amused while I'm stuck inside this winter. Thank you much. Looks like that amp measures out well. Hope it sounds pleasing. And if I stumble across anything interesting playing around with this I'll let you know.
I built a Power Supply that has stabilized adjustable voltage from 240-500V with up to 500MA and it has ripple less than 1mv over the whole range that is also placed above 22khz range. The power is so clean the amp it drives don´t need any power filters and the voltage you pick is stable within less than 1 volt even if you have big power swing in the tubes. so basically you pick a voltage and no matter what the amp or mains does your selected voltage stays the exact same even if your amp pulls heavy varying load from it. A DMM cannot measure any ripple at all, it is only with a sensitive scope you can measure a fraction of a millivolt of ripple above 22khz on this supply. but with that said if you drop my power supply on your foot you never walk on it again
Thanks for the excellent video. Is the 12V zener diode used to bias Vgs of the MOSFET to turn it on? So does this mean that there is 12V drop between the drain and source of the MOSFET? And you would use this to calculate the power dissipation of the MOSFET, and the heatsink required, correct? What is your thought on putting a LR8 voltage regulator from the node between R524 & C503 to the node below R1? Thanks again. I'm having a difficult time finding LTSPICE model for LR8 so I don't know how to simulate it.
The Zener is there to protect the gate from over-voltage. Very common in switching supplies but probably not necessary in this application and could be left out.
Saludos. Excelente Proyecto. Estoy haciendo un probador de tubos y quisiera construir este circuito para el modulo de HV. Hiciste alguna modificacion final?
Cuales son las caracteristicas de salida del transformador Toroidal que utilizaste para alimentar esa PCB?
Are you satisfied with the final design you showed? Would you be willing to share the schematic?
The schematic is shown in the video, I haven't changed anything so far but do have some updates in progress and will likely do another video in time.
@@myalbatech The schematic I saw in the video looked to be a single stage, rectified RC filter to a saturated FET capacitance multiplier. Which is basically what you described.
But you mention adding additional cap multiplier stages in series. Which would normally result in the full voltage being seen on both legs of the second and subsequent cap multiplier stages. Where as you look to be pulling multiple voltages from the voltage dividers in the tails of the FETs.
Which I've only seen possible if they are connected in parallel. Otherwise the FET doesn't saturate, limiting current.
Or are the voltages so high that it doesn't matter and the FET stays saturated regardless?
So I'm wondering how exactly you coupled the multiple stages together. Which isn't in the schematic I saw at the beginning of the video.
@@brookersmith8278 The FET stages are simply cascaded. Drop the values of R13 and R16 to form a potential divider at whatever voltage you want.
@@myalbatech Interesting. Cascaded, with proper component selection, it should also be possible to achieve substantial voltage regulation. At least at much lower voltages. Ive never played around with that outside of sub 3 volt logic circuits.
At these voltages, and with tubes, I'd normally be looking at shunt regulation.
But this should make for some fun experimenting in a 2A3 parallel feed SET circuit. Should keep me amused while I'm stuck inside this winter.
Thank you much. Looks like that amp measures out well. Hope it sounds pleasing.
And if I stumble across anything interesting playing around with this I'll let you know.