Dear folks,
I search for a solid state based PSU schematic for stabilized HT of +250V with max 15mA load. Input is ~325V. It should be "silent" means high ripple rejection as possible and as best safe against shorts on output. I want to use this for a small projet to supply only one tube ( ECC82 ) in a small case. As transformers I want to use two EI 38/16 connected against each other. The "middle" voltage of both transformers I want to use to supply the filament.
First unchecked choice was an TL 783 based one. But after reading some threats about this quite old knob I rejected this. I found a few schematic using MOSFET as a linear regulator but this need lot of external parts for a good ripple rejection and stability. The "dream" is to get something like an µa78XX for 250V
Does someone of you good fellows know an schematic which fulfil my requests?
Thanks a lot!
Karsten
I search for a solid state based PSU schematic for stabilized HT of +250V with max 15mA load. Input is ~325V. It should be "silent" means high ripple rejection as possible and as best safe against shorts on output. I want to use this for a small projet to supply only one tube ( ECC82 ) in a small case. As transformers I want to use two EI 38/16 connected against each other. The "middle" voltage of both transformers I want to use to supply the filament.
First unchecked choice was an TL 783 based one. But after reading some threats about this quite old knob I rejected this. I found a few schematic using MOSFET as a linear regulator but this need lot of external parts for a good ripple rejection and stability. The "dream" is to get something like an µa78XX for 250V
Does someone of you good fellows know an schematic which fulfil my requests?
Thanks a lot!
Karsten
Somebody already dreamed it...The "dream" is to get something like an µa78XX for 250V
http://www.supertex.com/pdf/datasheets/LR8.pdf
Convenient!
The datasheet is VERY incomplete- for example, there's no line noise/ripple rejection versus frequency data. And load regulation is pretty mediocre. I'll bet their next generation of regs will be just what tube guys need.
Actually, one simple application would be for use as a pre-regulator before an RC network. I'd still be inclined to use a Maida, but for apps where the current draw is low, this could save a couple parts.
MY amps are low noise and precise. Reasonably so, anyway.
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