let say I want to connect this regulator (+/-15V out ) to the CRC filter 1000uF -100R-1000uF
C- is some Panasonic FC/FM series
in details :
1C - 1000uF/50V Panasonic FC
R - 100R 0,6W
2C- 1000uF/25V Panasonic FM
distance beetwen CRC filter input ( on line stage board ) and output of the regulator
around 20 cm
Load - around 10 -60mA
Should I expect any regulator instability problems ??
C- is some Panasonic FC/FM series
in details :
1C - 1000uF/50V Panasonic FC
R - 100R 0,6W
2C- 1000uF/25V Panasonic FM
distance beetwen CRC filter input ( on line stage board ) and output of the regulator
around 20 cm
Load - around 10 -60mA
Should I expect any regulator instability problems ??
No, there will be no problem with instability.
But you should realise that in this setup you loose almost all of the benefits of a low output impedance, low noise regulator.
If you want to use the C-R-C it'd be easier and cheaper to use a simple LM317/337 regulator.
Jan
I have updated the Schematic and PCB to V2.2 in two areas:
- added a SOIC footprint for the opamp so now you can use either DIL08 or SOIC08 without adapter;
- added an RC filter to the remote sense line to improve stability for cases with unusually long remote sense lines.
The boards being shipped from now on will be V 2.2.
The article describing the design with schematics and board layout is also updated.
Enjoy!
Jan
- added a SOIC footprint for the opamp so now you can use either DIL08 or SOIC08 without adapter;
- added an RC filter to the remote sense line to improve stability for cases with unusually long remote sense lines.
The boards being shipped from now on will be V 2.2.
The article describing the design with schematics and board layout is also updated.
Enjoy!
Jan
Alternate voltage resistor values
I've read through the documentation for the regulators and found the resistor value table in "Part 2" Table 1. I've compared the schematic in "Part 2" with the diyaudio boards and I've come to this conclusion:
Old_New
R1=R4
R3=R7
R4=R6
R6=R5
Is that correct?
Thanks
I've read through the documentation for the regulators and found the resistor value table in "Part 2" Table 1. I've compared the schematic in "Part 2" with the diyaudio boards and I've come to this conclusion:
Old_New
R1=R4
R3=R7
R4=R6
R6=R5
Is that correct?
Thanks
Given the high tolerance of the electrolytics, you could already assume that you can. A 120uF might be between 96uF and 144uF with a 20% tolerance, so no good designs should rely on the absolute values.
If you dig up the thread, you might also see that the feedback cap could be smaller, and the zener filter cap can also be smaller, but gives slightly less attenuation. The output capacitor should be fine too, I suppose - I don't think Super Regs are designed to become instable with a slight output cap change.
Just don't use a super low-esr cap at the output cap position, however. Compare datasheets of the caps you will use with the Panasonic FC.
Jan could also justify my remarks, as soon as they are valid.
Given the high tolerance of the electrolytics, you could already assume that you can. A 120uF might be between 96uF and 144uF with a 20% tolerance, so no good designs should rely on the absolute values.
If you dig up the thread, you might also see that the feedback cap could be smaller, and the zener filter cap can also be smaller, but gives slightly less attenuation. The output capacitor should be fine too, I suppose - I don't think Super Regs are designed to become instable with a slight output cap change.
Just don't use a super low-esr cap at the output cap position, however. Compare datasheets of the caps you will use with the Panasonic FC.
Jan could also justify my remarks, as soon as they are valid.
100% correct, thanks.
Jan
I'll suspect that Walt J had such in his drawers. 120 uF is a very odd value these days but Farnell has it and also 180 uF some other odd values.
Thanks Jack and Jan for your responses
Could you please explain how does that 'LM317/337 pre-regulators with AD825AR' super regulator compare to the (newer?) one this thread is about?
And to use this one, will I need to remove all the very low impedance banks of caps that are across all the loads on all the circuits I currently use? Eg, the three paralleled 820uF polymer cap's each with a stated 5 mOhms Z (so that maybe 1.6 mOhms?) across the DAC chip voltage reference pin to earth? There because they sounded best so far.
I worked my way up to this kind banking over the years of careful listening test trial are error. Will this super regulator beat that kind of thing?
Sorry for asking these, no doubt, many times already asked questions, perhaps you could link me to already written answers? That would be most kind and save me from months of trawling threads and websites to find these succinct gems of knowledge.
Thanks.
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No those banks are perfectly allright, provided they don't cause the reg to oscillate. It happens sometimes with very low ESR caps across the outputs. But from your description I understand that they at the load, at some distance from the reg. That interconnection distance (inductance) probably is enough isolation at very high frequencies where it might osciallate.
But you might want to check for excessive noise on the power supply line which would indicate oscillation.
Jan
But you might want to check for excessive noise on the power supply line which would indicate oscillation.
Jan
Yes should be no problem. The 797 version *might* be a bit lower noise, but you should verify stability.
I have not tried that so cannot comment on it.
Jan