The simplistic Salas low voltage shunt regulator

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diyAudio Chief Moderator
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Aha! The noise thing I had experienced for a Jung DN+LM as plate load wasn't some mistake but intrinsic. Thanks for suggesting the additional paper with the answer. I hope its OK I attach just an explaining excerpt.
 

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There is one thing which I would like to know that what if the voltage is dropping substantially with bib. Like Consider the psu input voltage to the bib being 25V and the regulated level output from the bib is 18V and what if the voltage drops to 16V from the psu now the regulation doesnt happen beyond the reference but does the functionality of the bib will be shut down or does it work still providing 16V but does the noise performance will still be acceptable or it is as good or just slightly less than the one which is regulated.

Overall does the device gets shut down because of such drop. With the simulation what I found is that the voltage at the output of the reg is dropped and current is still being deliverd but what about the noise and impedance?
 
diyAudio Chief Moderator
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The regulation will stop and the main CCS will quit its setting. Vout will be following Vin, current will keep passing just as the load pulls at this lowered rail plus few mA that some of the reg's minor branches will keep on pulling. In other words it will behave like some kind of a passthrough route.
It won't add detectable noise. Even less than when it was working. Zout will be about as much as R1 (the CCS setting resistor) for a large portion of the audio band before it will begin to taper off into something like one fifth to one tenth of its low frequencies initial value when in the ultrasound region and beyond.
 
diyAudio Chief Moderator
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I did not recognize it as directly mine because it looks different coming from your Eagle files, plus it has a couple of small additions. Mystery solved.

Yes you can replace your Q1 Q3 CCS Mosfets with IRF610 IRF9610 but the Q4 Q8 output ones must be IRF530 IRF9530.
 
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