About Jung super regulator

[MaxS]

Hello

After readings about regulatots, I have Jung super regulator ( schematics attached ) but I'd get your advice about some substitions parts.

AD 825

• JFET input
• High output current

I want to replace it with TL 071 but i'm afraid by a low output current of this one which makes the transistor didn't provide too much current in the case of an HFE around 40. Otherwise, i canuse a most expensive one as OPA 13x.

2N5087
I've read I can replace it with 2N2907, so I can replace it with a BC 327. Am I wrong ?


Yhanks you for your help

[AndrewT]

Hi,
5087 is a CCS.
Since the circuit works well at high speed I would expect the transistor to also be highish in speed and similar (or better) gain.

[mitwrong]

MaxS:
Analyze the schematic provided, the output tr. better replaced by a darling ton. and the ccs 2n5087 is redundancy, Just a single resistor could do the job fine. it only provides the bias current to drive the output stage, due to an IC is employed for error amp, also U use a LM317 for pre-reg. this psu is good for most application, more than enough as a bench supply. IC is better to choose a high slew rate, then any change of the output voltage can immediately corrected.

Your IC took the voltage from the output side is not advised, it better get the voltage from a regulated source.




WE IMPROVE BETTER DESIGN

[janneman]

Originally posted by mitwrong
MaxS:
Analyze the schematic provided, the output tr. better replaced by a darling ton. and the ccs 2n5087 is redundancy, Just a single resistor could do the job fine. it only provides the bias current to drive the output stage, due to an IC is employed for error amp, also U use a LM317 for pre-reg. this psu is good for most application, more than enough as a bench supply. IC is better to choose a high slew rate, then any change of the output voltage can immediately corrected.

Your IC took the voltage from the output side is not advised, it better get the voltage from a regulated source.




WE IMPROVE BETTER DESIGN

As being involved in the development of the 'Jung' superregulator, you CANNOT replace the CCS by a resistor and expect the same performance. ALL parts of this design are carefully selected to give overall top performance. Before starting to modify it (which will most likely make things worse anyway) you MUST read the articles.

Taking the opamp supply from the REGULATED output is REQUIRED for this performance. Taking it from the source will make performance worse.

I am afraid that your 'advises' make a good design worse...

A TL071 will have no output current problems; the max output current depends on the ccs current and not on the opamp. However, the '071 has less gain at higher frequencies so the Zout will increase and the ripple and noise rejection will be a bit less at the top of the audio spectrum with respect to using one of the recommended high speed opamps. Whether you can hear that depends on a lot of other factors, you could just try it out.

Jan Didden

[mitwrong]

Jan Didden:

I do learning English, but I will never speak to a Lawyer.

May be my suggestion makes your design worse? I pointed out the reason is base on theory, have you try and test them?

I was a psu designer, would you give a comparison on the item below and see the difference?

Regulation:1 at no load
2 at full load
3 from load to off load ( transient )
4 ripple
5 holdup time ( rise and fall time )
6 noise ( spikes )
7 input AC variation ( + - 20 % )
8 stability ( change in volts duration for 8 hrs )

IC works better on regulated voltage, If the supplied voltage varies, the working condition will be change, as you use the ic as voltage error amplifier, with the supplied voltage varies, would you get stable output?

With constant current supplied to the series output transistor base, also the output of U1, How can Ib of Q1 change?

Have you checked for circuit oscillates?

This is Forum! not a place for arguing, I just point out what we have seen, From our experience, your circuit seems has a little problem. ( not at good working condition )

I've been study the cct. from famous brand psu manufacturer like Kepco, Lambda, Soresen, TDK, Astec ------etc, nothing designed as such like???????




WE CHECK CCT. LOGICAL AND SENSIBLE

[Nordic]

Mitwrong, thanks for the thought provoking post. Would you care to post a full schematic of your modified version?

[AndrewT]

Hi Mit,
this Forum is a place for arguing.
It's the traditional and expected way we exchange views.

That way some may come to change their view for better or worse or to expand one's knowledge.

Long may the arguments continue!

[AndrewT]

Hi Mit,
let's see how you have changed the Jung Super Reg and give us some comparative measurements for the parts of the spec you have managed to improve.

[mitwrong]

Nordic, Andrew T:

Thanks for your supports, Argument is accept, but don't pin point on person! We just want to discuss technical matter, design, schematic, or material ( parts ). The way we argue is base on facts, theory, results, experience, supporting figures.
sometimes may use logical sense. That's the way what we like.

For the schematic Nordic requested, I will post till I have drawn it.
Sorry for delay.



WE ARGUE WITH TECHNICAL SUPPORTS

[janneman]

Originally posted by mitwrong
Jan Didden:

I do learning English, but I will never speak to a Lawyer.

May be my suggestion makes your design worse? I pointed out the reason is base on theory, have you try and test them?

I was a psu designer, would you give a comparison on the item below and see the difference?

Regulation:1 at no load
2 at full load
3 from load to off load ( transient )
4 ripple
5 holdup time ( rise and fall time )
6 noise ( spikes )
7 input AC variation ( + - 20 % )
8 stability ( change in volts duration for 8 hrs )

IC works better on regulated voltage, If the supplied voltage varies, the working condition will be change, as you use the ic as voltage error amplifier, with the supplied voltage varies, would you get stable output?

With constant current supplied to the series output transistor base, also the output of U1, How can Ib of Q1 change?

Have you checked for circuit oscillates?

This is Forum! not a place for arguing, I just point out what we have seen, From our experience, your circuit seems has a little problem. ( not at good working condition )

I've been study the cct. from famous brand psu manufacturer like Kepco, Lambda, Soresen, TDK, Astec ------etc, nothing designed as such like???????




WE CHECK CCT. LOGICAL AND SENSIBLE

I worked on this circuit with Mr Jung. I invite you to replace the ccs with a resistor and compare your measurements with ours.
If you want comparative data, please see the article series in Audio Amateur with full curves and specs.

Also, please look again at the circuit. The opamp IS supplied from the regulated output voltage.

You apparently do not really understand the workings of the regulator, if you say 'how can it work with a constant current?'. The base current changes because the opamp regulates the difference between the ccs and the required base current. Using a ccs instead of a resistor means that the loop gain is much greater; the opamp works with a load of the very high dynamic impedance of the ccs versus the much lower impedance in the resistor case. And, the higher the dynamic resistance, the higher the loop gain and the tighter the regulation.

If you would read the article series in Audio Amateur in I think 1994, there is a whole section where I explain stability issues and oscillation and make recommendations for the best opamp.

BTW, your suggestion to replace the series transistor by a darlington will virtually guarantee oscillations due to the increased gain with increased phase shift within the loop.

And please, don't compare a high performance circuit like the Jung reg with run-of-the-mill Lambda or Kepco. There is really no comparison!

Jan Didden