This is not to say that nonsense isn't nonsense, but a cap multiplier only filters what comes from upstream. Downstream disturbances such as load variations will get flattened by a Jung reg or comparable circuitry, but not by a cap multiplier, which doesn't regulate. This in defense of regulators.
Seperate issue, someone above posted that a Jung super reg would also work to filter RF from the supply lines. However, at RF the output impedance of regulators (including the leads to where the juice is needed) gets fairly high and I would recommend local caps for that.
edit: Too strongly worded. What I intend to say is that the cap multiplication does only work one way. The incorporated capacitance of course delivers short term current on load fluctuation, but only in conformity with their nominal value, not multiplied.
Last edited:
Yes, the Jung techniques work brilliantly up to about 100kHz, but from there parasitics become everything - extremely competent bypassing is the way to go from then on ...
RFI should be eradicated fiercely, as close to the source as possible. This is why both cleaning the mains supply before entering the equipment, or, alternately, right at the entrance to the equipment and EMI resistant enclosure are important, along other things.
I'm yet to see a voltage regulator that does a better job than the Jung's one.
Except, I see passives doing a better job than active circuitry, at the higher frequencies - it's a fine balancing act getting decent attentuation over a broad spectrum, as people have been saying.
A very crude test setup I use, that I've mentioned before, is plugging a high wattage incandescent lamp into the mains right besides the plugs of the audio gear, and then deliberately physically playing with the mains connection to that lamp, making it arc savagely. With normal audio gear the massive interference levels generated that close make the speakers go beserk with static; I've managed to totally silence the system's reaction ...
A very crude test setup I use, that I've mentioned before, is plugging a high wattage incandescent lamp into the mains right besides the plugs of the audio gear, and then deliberately physically playing with the mains connection to that lamp, making it arc savagely. With normal audio gear the massive interference levels generated that close make the speakers go beserk with static; I've managed to totally silence the system's reaction ...
I'd love to see your entire solution. Maybe some other people here may be benefited from it.
Trouble is, I'm not in good enough financial shape to freely give away my "secret sauces' - sorry about that ... 😀
My response to Joshua_G was a bit harsh. I apologize.
I just don't think throwing a Jung reg into a preamp without thinking about all the other stuff going on around it helps.
As fas42 points out, above 100 kHz, it's parasitics that dominate. The Jung is quiet, but I like to use a regular 317 and then heavily decouple/filter right at the opamp or active circuitry. You can get to c. 10 uV of regulator noise (so excl. load noise) and after you factor in PSRR, the input referred noise is nV.
I just don't think throwing a Jung reg into a preamp without thinking about all the other stuff going on around it helps.
As fas42 points out, above 100 kHz, it's parasitics that dominate. The Jung is quiet, but I like to use a regular 317 and then heavily decouple/filter right at the opamp or active circuitry. You can get to c. 10 uV of regulator noise (so excl. load noise) and after you factor in PSRR, the input referred noise is nV.
Now that John is nonsense.
You complain that I pose as a PSU expert and then straight after that we all get a lecture about your standing in the industry as a designer.
I don't claim to know everything about power supplies as you put it - far from it - but when things go off on a tangent, I feel quite happy popping a few egos around here.
Chill.
😎
Last edited:
BTW, Kendall Castor-Perry has written a very good series of articles on PSU's - covers a lot of the stuff we have touched on here and he also discusses how to model some of the issues specifically around the regulators. He had a series in EDN, but this is the link to Jan Didden's site:-
http://www.linearaudio.nl/linearaudio.nl/images/pdf/bypass_capacitors_part1.pdf
http://www.linearaudio.nl/linearaudio.nl/images/pdf/bypass_capacitors_part1.pdf
+1 for KCP's contributions, always valuable IME. However I note he's doing modelling of skin effect - to be taken seriously here he'd also need to be modelling proximity effect. The difficulty of modelling this is why I've gone over to building things, rather than modelling them 🙂
Amazing what PSRR looks like when you start to model in trace inductance and capacitor ESR and ESL. Suddenly, it aint so good anymore. Thats one of the reasons I've gone over to heavy class A biasing in small signal stages - seems things are a bit better if the signal related currents are a fraction of the total load current rather than the other way around. But, more of that when I finish my latest effort in a few months time.
I might point out Bonsai, that you could learn a lot faster, IF you would just let the successful audio designers contribute more freely here.
For the record, in the last 40 years, I have tried just about every kind of power supply for a multitude of designs, including studio boards, master tape recorders, preamps, pre-preamps, power amps and electronic xovers. I have tried and failed, sometimes, to make an ideal power supply. Sophisticated solutions do not necessarily come on the first try, but from a combination of engineering and experience, with REAL feedback from listeners and users.
For the record, in the last 40 years, I have tried just about every kind of power supply for a multitude of designs, including studio boards, master tape recorders, preamps, pre-preamps, power amps and electronic xovers. I have tried and failed, sometimes, to make an ideal power supply. Sophisticated solutions do not necessarily come on the first try, but from a combination of engineering and experience, with REAL feedback from listeners and users.
As a convenience, here are the 6 parts in one document, from an appropriate site, 😉 ... www.ap.com/download/file/678
It is almost impossible to give added information on this thread regarding precisely why the thread exists in the first place. Every time we try to discuss a potential improvement in an audio design, we are always interfered with, with negative comments, even insults.
For example, it took me a week to work in the subject of cleaning component leads, and then I still got back-wash about how it isn't very important, or flux does it all, etc.
Now, people try to give their input on a superior regulated supply, and we get the same sort of put-downs, about how it isn't necessary, etc. If you don't want to give something useful, why comment at all?
For example, it took me a week to work in the subject of cleaning component leads, and then I still got back-wash about how it isn't very important, or flux does it all, etc.
Now, people try to give their input on a superior regulated supply, and we get the same sort of put-downs, about how it isn't necessary, etc. If you don't want to give something useful, why comment at all?
John,
I did not say a good PSU design was uncessessary and I do not see how I am stopping the successful designers from contributing. I dont happen to think a Jung reg is required to qualify a supply as good. Just like JFET's on the front end of an amplifier instead of bipolars. Or opamps. PSU design is not the only subject on this thread that seems to have drawn yours and a few others ire.
Like so many things, there are many ways to solve a problem successfuly. But, let me not open another can of worms because we all know it will not move anyone from their entrenched positions.
Thanks for the link fas42
I did not say a good PSU design was uncessessary and I do not see how I am stopping the successful designers from contributing. I dont happen to think a Jung reg is required to qualify a supply as good. Just like JFET's on the front end of an amplifier instead of bipolars. Or opamps. PSU design is not the only subject on this thread that seems to have drawn yours and a few others ire.
Like so many things, there are many ways to solve a problem successfuly. But, let me not open another can of worms because we all know it will not move anyone from their entrenched positions.
Thanks for the link fas42
Last edited:
If things are really critical I like to provide local shunt regulation, so from the perspective of the more distant main regulators the load current is practically constant. Also currents in "grounds" are nearly constant. Of course this is at cross-purposes to power consumption.
Even with fast shunt regs you will not get sufficiently rapid response in some situations. Then you may be advised to sample the signal ahead and with a "plant model" enact precisely-timed compensatory corrections. With deterministic fast pulse generation, compensating loads can be driven to render the power supply drain constant, or with even more parts a balanced system can be used, even if the ultimate outputs are single-ended. I did many of these things in a spectrometer back in the late '70s, a project that took four years of probably 12-15 hour days and usually 7 day work-weeks before the main power switch for the whole system was flipped on. Although it seemed unlikely that the techniques would be applicable to audio, the faster things get, particularly with hybrid digital-analog and switchmode systems, the more relevant they seem to become.
- Status
- Not open for further replies.