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Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
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Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
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In Reply to: Thank you for the link, Tré posted by 1973shovel on February 3, 2022 at 06:30:04:
I use critical inductance choke input filters LCLCRC on my heater supplies for my preamp and driver tubes. The filament supplies for my direct heated output tubes also use critical inductance choke input filters LCRCL.
The definition of "critical inductance" is the inductance value that, in a given situation, keeps the diodes (each in turn) on for it's entire half cycle. This keeps the peak current no higher than the load current.
With a less than critical choke input filter (or a cap input supply) the diodes (all of them) are off most of the time so the current has to be high (multiple times the load current) when they are on.
The same amount of "power" still has to be delivered to the load but because the time when the diodes are on is short the supply has to "make hay while the sun shines" so the current has to be high. These current "Spikes" are the problem in terms of noise.
You can clearly see all of this with the Duncan power supply designer II modeling software. Or a scope.
Tre'
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Follow Ups
- RE: Thank you for the link, Tré - Tre' 02/3/2208:34:53 02/3/22 (3)
- RE: Thank you for the link, Tre' - 1973shovel 19:33:52 02/3/22 (2)
- RE: Thank you for the link, Tre' - Tre' 19:42:13 02/3/22 (1)
- "a lot of capacitance" - 1973shovel 06:56:11 02/4/22 (0)
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