Jan,
I'm trying to simulate the Sulzer regulator you used on that old TAA I/V Philips DAC you
designed. Did you use 7X08 or 7X05 as references?
From those old projects, your passive amplifier filters, particularly for high pass and low pass, to use with subwoofers, I think were very interesting.
One question: at the time you used MJE200 and MJE210 as pass transistors. Are a valid option to use on a Jung regulator too?
I'm trying to simulate the Sulzer regulator you used on that old TAA I/V Philips DAC you
designed. Did you use 7X08 or 7X05 as references?
From those old projects, your passive amplifier filters, particularly for high pass and low pass, to use with subwoofers, I think were very interesting.
One question: at the time you used MJE200 and MJE210 as pass transistors. Are a valid option to use on a Jung regulator too?
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I don't remember, I think 7805 but it really doesn't matter, both can be used. Or any other reference like the LM629.
The MJE200/210 are very nice transistors, and would be nice for a regulator due to their high current gain-bandwidth and 5A capability. They have a high Ft so stability should be verified.
Did you get that AD825 going?
Jan
The MJE200/210 are very nice transistors, and would be nice for a regulator due to their high current gain-bandwidth and 5A capability. They have a high Ft so stability should be verified.
Did you get that AD825 going?
Jan
If you don't want to wait:
From LTspice, open the symbol AD844A.asy (check the name I don't remember exact);
Then click Edit|Attributes|Edit attributes from the top of the screen;
In the window that opens you see an entry for Modfile where the path to the .cir is shown. That is a path on my PC ... Replace that with the path to where you have stored the .cir on your PC, click OK and then File|Save.
That's all.
Jan
From LTspice, open the symbol AD844A.asy (check the name I don't remember exact);
Then click Edit|Attributes|Edit attributes from the top of the screen;
In the window that opens you see an entry for Modfile where the path to the .cir is shown. That is a path on my PC ... Replace that with the path to where you have stored the .cir on your PC, click OK and then File|Save.
That's all.
Jan
Sent it two times and message got back. Something missing?
Of course I replaced at with @ and dot with .
... but I'll suppose that the speed will be slower since darlingtons always are slower.
The issue is the base current for the pass device. In the min output current, all the available base current from the current source has to be absorbed by the opamp.
For the AD825 that max is about 50mA but for good operation it should be limited to half that, say 25mA. So the current source can be set to max 25mA, and that means a 1A output current with an Hfe of 40 of the pass device.
The D44H11 has a min Hfe of 60, so that 1A should be no problem, but not much higher. Assuming proper heatsinking of course.
The BD681 for example has an Hfe of 750 min.
But note that with Darlingtons you need more dropout voltage across the pass device which may also increase dissipation.
I don't know the relative Ft of these devices but with modern devices I doubt it will be an issue in a Superreg.
Jan
For the AD825 that max is about 50mA but for good operation it should be limited to half that, say 25mA. So the current source can be set to max 25mA, and that means a 1A output current with an Hfe of 40 of the pass device.
The D44H11 has a min Hfe of 60, so that 1A should be no problem, but not much higher. Assuming proper heatsinking of course.
The BD681 for example has an Hfe of 750 min.
But note that with Darlingtons you need more dropout voltage across the pass device which may also increase dissipation.
I don't know the relative Ft of these devices but with modern devices I doubt it will be an issue in a Superreg.
Jan
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Worth mentioning is that you have to consider the power dissipation of the opamp. It could be quite much if you have a high output voltage.
I've decided to go in exactly the opposite direction: an AC wall wart with a single secondary and no center tap. I prefer this because it completely removes the AC mains from the DIY chassis, so the risk of electric shock is far less. I also like the fact that it pulls the big voluminous bulk of the transformer out of the chassis, letting me consider very thin enclosures like "1U height" or even smaller.
This decision does come at a cost, of course. It needs two half wave rectifiers to make +15VDC and -15VDC outputs, so either the peak to peak ripple voltage is twice as big, or else the filter capacitors are twice as many microfarads. It also forbids stacking two identical regulators. Despite those drawbacks, that's what I've chosen for the past year and a half, and so far I'm still pleased.
Time to bring my findings on the LTSpice thread to the Super Regulator thread.
Jan, is it possible to get better graphs from Jack Walton to compare them with the LTSpice graphs? Or is that asking too much?
Just could insert the AD797 on the sim. The sim is available to anyone who wants it.
The best psrr of all the opamps, but the 797 continues to be the most non-recommended choice for the Super Reg, in spite of being the one with best specs.
Today I knew you also need an external compensation cap to stabilize it.
Will there ever be a totally reliable combo for the 797 or should it be wiped out of the choices for the Super Reg?
Jan, is it possible to get better graphs from Jack Walton to compare them with the LTSpice graphs? Or is that asking too much?
Just could insert the AD797 on the sim. The sim is available to anyone who wants it.
The best psrr of all the opamps, but the 797 continues to be the most non-recommended choice for the Super Reg, in spite of being the one with best specs.
Today I knew you also need an external compensation cap to stabilize it.
Will there ever be a totally reliable combo for the 797 or should it be wiped out of the choices for the Super Reg?
If you go to: Downloads | Linear Audio ...
... and scroll down to almost the end you find a chapter titled:
Color graphs for Jack Walton's regulator article in Vol 4.
Jan
... and scroll down to almost the end you find a chapter titled:
Color graphs for Jack Walton's regulator article in Vol 4.
Jan
Thanks, Jan. Having those curves will be a great help to make comparisons with sims.
Now there's something I would like your opinion of. The first time I read Walt talking about output impedance figures, I was left with the impression that it was a data that really showed a strong influence on the audio quality of what was being powered. Even more than noise or psrr. Was I wrong in my assumption?
It was very similar to when I read about Louspeaker impulse response and CSD response. They are a faithful or more accurate or approximate idea on how a speaker will sound in real life, more than FR response curves or even distortion.
The latter I have lead all my life with paying attention to, because I was a professional film & TV sound engineer, coming from the mid '70s, what I call my Nagra and Sennheiser times, and my search had always been for a real approximation with the natural sound, human voice in those times, but also natural sounds, nature sounds. So monitors were critical and very rarely "told the truth".
So how to relate measurements to "real sound" has been my life quest. Please do forgive my large ignorance in electronics, which you always detect and many times tries to help me with. Believe me that it's very much frustrating when I can't answer your questions.
In spite of all that, I spend most of the time cheating and finding "my way" to still be around in spite of my ignorance. And I do know you have been more than patient many times, and a real teacher. You and many others, I don't forget any.
I still believe I can still play in spite of all my limitations.
Now there's something I would like your opinion of. The first time I read Walt talking about output impedance figures, I was left with the impression that it was a data that really showed a strong influence on the audio quality of what was being powered. Even more than noise or psrr. Was I wrong in my assumption?
It was very similar to when I read about Louspeaker impulse response and CSD response. They are a faithful or more accurate or approximate idea on how a speaker will sound in real life, more than FR response curves or even distortion.
The latter I have lead all my life with paying attention to, because I was a professional film & TV sound engineer, coming from the mid '70s, what I call my Nagra and Sennheiser times, and my search had always been for a real approximation with the natural sound, human voice in those times, but also natural sounds, nature sounds. So monitors were critical and very rarely "told the truth".
So how to relate measurements to "real sound" has been my life quest. Please do forgive my large ignorance in electronics, which you always detect and many times tries to help me with. Believe me that it's very much frustrating when I can't answer your questions.
In spite of all that, I spend most of the time cheating and finding "my way" to still be around in spite of my ignorance. And I do know you have been more than patient many times, and a real teacher. You and many others, I don't forget any.
I still believe I can still play in spite of all my limitations.
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