Hi, Thanks for the inputs. The reason for the drop is the PS is being used to provide 240 VDC for part of the circuit and I want to add something that needs the lower voltage. CRC filtering was not enough and there is no room for a choke etc. I can use the chassis for a heat sink so that heat is not a concern. I don't have ripple measurements at this time and may have to take some. I estimate from the breadboard hum that I need about 30 db of better filtering over a simple single stage CRC. It is the 4th in the string with the other 3 going to the rest of the cirrcuit. I'll post the project when I can get to my satisfaction. I was looking at something like what Mike567 posted, but figured it would cut the B+ down, but not clean it up enough.
Then again, maybe I am being fanatical again about hum and noise. It is there
, I can hear it and I want it gone.
Good listening
Bruce
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I didn't know whether to post this here or in the Solid State section. Since it is going to be part of a tube design I figured here was better. Get out your thinking caps and sim programs. I have a design that needs to drop B+ from 240 to about 140 at 50ma and filter it really well. It would seem that a FET based series filter stage in the PS would do this as the third one in a string of CRC ones. Regulation is not all that important, but the drop and filtering are. I am considering bootstrapping a LR8 with something like and IRF820 (or 730 as I have both). It would seem that the filtering and regulating properties of the LR8 would be passed on to the FET and provide enhanced filtering. The adjustable output is a plus and regulation ought to be excellent. Any thoughts on this?
