Kay is right: from tubecad.com: "... The Janus regulator is not a DC voltage regulator, as it cannot maintain a fixed B+ voltage; instead, it works to eliminate any AC perturbations on its output voltage..."
I'm also looking into an all-tube power supply for a preamp, and I'm evaluating various topologies.
I'm also looking into an all-tube power supply for a preamp, and I'm evaluating various topologies.
Kay is right: from tubecad.com: "... The Janus regulator is not a DC voltage regulator, as it cannot maintain a fixed B+ voltage; instead, it works to eliminate any AC perturbations on its output voltage..."
I'm also looking into an all-tube power supply for a preamp, and I'm evaluating various topologies.
This topology works well, it came out of an old RCA tube manual, I’ve built this a few times, it’s very quiet, and you can use just about any power pentode or triode for the pass device, depending on your current requirements, the only substitutions I’ve made is to use a zener diode for the reference.
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Thanks, interesting cicuit. Left of R7 is a nice place to add a capacitor to filter out the voltage reference generated noise. I'm looking into something not too far off: a differential amplifier with a buffer (pass).
Maybe I'll run a sim on these circuits sometime.
Yes I believe I inserted a cap there, and I made some changes to the voltage divider, so that a 1/2 watt trim pot could be used. I’ve run this one already, I’ll post it sometime.
"bien sûr, je suis aussi à la retraite"You have to understand how busy the life of a retiree can be
When you set the sim for the ecl82 psu, did you tooked into consideration the rectifier and the CLC filter?Here’s the simulation, using an EL34 tube. Noise figures
Look excellent, total output noise is 200nW @ 40mA at 0Hz. The ripple
Voltage at least 1mV or even less. Someone could convert this figure for me.
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Yes, that's true. The main difference to the schematics in #37 is that we have a voltage reference here, while in #37 there isn't any. No reference, no regulation. It's really that simple.This topology works well, it came out of an old RCA tube manual, I’ve built this a few times, it’s very quiet, and you can use just about any power pentode or triode for the pass device, depending on your current requirements, the only substitutions I’ve made is to use a zener diode for the reference.
Best regards!
This is what I have in mind at this time: a simple diff amp (LTP) with a buffer (CF). I'm pretty sure it'll work, but I haven't built it, yet.
The pro's:
The pro's:
- Very low open loop gain, no compensation required
- Using a precision 85A2 voltage reference, because I have a big handful of those
- Simple all triode design
- Limited PSRR, about 20DB at 100Hz, because of the low Ri of the cathode follower
- Limited load regulation, for the same reason
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