Hi Jan, a quick question. I am building two 5V Super Regulators for USB. The load current is around 250mA each. The power sources are two separate 13V LiFePO4 batteries. I’ve built one regulator using the positive board and it works great. I want to build the second regulator using the negative board. Is there anything to keep in mind or any disadvantages of using a negative board (with the specified “negative” parts) to be used as a positive power supply for USB? (Using the ground of the regulator as the positive output.) Is this worse than using a positive board or completely equivalent? I am looking for a low output impedance at the USB-Audio frequency (USB 2.0 480Mb/s). The positive board seems to give great results. Thanks so much for your insight!
I can't see any disadvantage, it's a great idea if you can keep the input sources isolated from each other, as you plan.
In theory, the negative regulator performance is slightly less than the positive reg, but that is as said more in theory, with no practical consequences.
Go for it!
Jan
In theory, the negative regulator performance is slightly less than the positive reg, but that is as said more in theory, with no practical consequences.
Go for it!
Jan
Thank you Jan! BTW the Super Regulator yields the best sound quality compared to anything else I’ve tried, including other high-end DIY boards, ultra capacitors with custom filters, and some commercial supplies. My DAC, Aqua La Scala (PCM1704K with Telefunken ECC801S), is very sensitive to the quality of the USB power. The Super Regulator sounds remarkably clean finally removing this critical bottleneck in my system. Thank you for making this wonderful design available to everyone! -Alex
@safesphere -- methinks that the SR sounds best as it imposes no harmonics onto the power rails -- to our little group of audiophiles it was startling apparent in the arena of cymbals, drums and bells.
Mind you, the originals were published by Walt Jung 25+ years ago.
I use the SR in a modded pre and it's been running non-stop for over a decade. For instrumentation and measurement I use the "Silent Switcher" which can be run on a pair of 18650's lithium ion batteries and is quite compact.
Mind you, the originals were published by Walt Jung 25+ years ago.
I use the SR in a modded pre and it's been running non-stop for over a decade. For instrumentation and measurement I use the "Silent Switcher" which can be run on a pair of 18650's lithium ion batteries and is quite compact.
It's even older than that, Mr. Kaneda from 1977 and Philbrick 5910-C regulator from 1961 made out of tubes.
Bob Pease wrote about the tube super regulator can be found here
https://cdn.baseplatform.io/files/b...ocuson_bobpeaseonanalogvol2.6026a0db15766.pdf
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Big thanks to everyone indeed and especially to Jan who personally recommended the SR to me! I haven’t tried it with an AC rectifier. Is there an audible difference? I have compared a battery against AC (no snubber) with a different high-end regulator for USB and the sound difference was dramatic. Also, is there any difference in the sound quality depending on the input voltage? The other regulator I tried sounded better with 24V than with 12V, but still not as good as the SR.
Also, does it make any sense to try a discrete opamp? Here is a random example: Sparkos Opamp 8Pin DIP Single Many audiophiles use discrete opamps in the audio path, but would there be any benefit in the SR? Perhaps unlikely, but I wonder if anyone has tried.
Hi Jan, I have another question 
Inspired by the great performance of the SR, I wonder if I can try AD817. I know you don’t recommend it in general, because of the instability issues, but I’d be willing to try if it behaves in my setup. I have a 100MHz digital desktop o-scope, but little experience with opamps. Could you possibly please advise what to look for and where to measure to check if the build is stable? I can start by using a resistor as a load, so no harm is done even if the build goes up in a smoke Thanks so much again!
Inspired by the great performance of the SR, I wonder if I can try AD817. I know you don’t recommend it in general, because of the instability issues, but I’d be willing to try if it behaves in my setup. I have a 100MHz digital desktop o-scope, but little experience with opamps. Could you possibly please advise what to look for and where to measure to check if the build is stable? I can start by using a resistor as a load, so no harm is done even if the build goes up in a smoke Thanks so much again!
My bad. I did mean AD797. Thank you! However, I see that AD817 is about twice faster than AD825 (if I am reading it right). So I guess a bigger question is, what properties of an opamp are most important in this circuit? And also, is there anything between AD825 and AD797, both stable enough and higher performance?
Noise is obvious but when equally low, I think OLG of AD797 is important. I forget but there is a cheaper opamp that has OLG almost as good as AD797, which I believe is a good candidate.
Noise is an important parameter here. Discrete opamps won't be at the level of AD825/797 etc.
Noise from the specs in nV/vHz:
Sparcos - 3
AD825 - 12
AD797 - 1
It looks like the discrete is between 825 and 797 by noise?
Also, is a random noise what defines the sound quality? What do you think of a correlated noise? What I mean is essentially the voltage drop on the load. For example, a USB signal is digital - all or nothing at 480Mb/s. When the demand jumps from 0 to 1, the output voltage of the regulator momentarily drops likely by more than the random noise value. How fast it recovers seems critical, no? I’m not an expert, just thinking out loud here
Thanks!Noise from the specs in nV/vHz:
Sparcos - 3
AD825 - 12
AD797 - 1
It looks like the discrete is between 825 and 797 by noise?
Also, is a random noise what defines the sound quality? What do you think of a correlated noise? What I mean is essentially the voltage drop on the load. For example, a USB signal is digital - all or nothing at 480Mb/s. When the demand jumps from 0 to 1, the output voltage of the regulator momentarily drops likely by more than the random noise value. How fast it recovers seems critical, no? I’m not an expert, just thinking out loud here
Oh I didn't think you were referring to a high quality ready-made discrete opamp. Even though the noise is high they MIGHT sound preferable to my ears.
If you ask me, I don't think (wideband) noise is important at all
I have preferred the sound of an ancient opamp with high noise in the SR circuit.BTW, the LM317 pre-regulator (often omitted) is audibly important too.
Actually Jung had a unique way of incorporating the LM317 to the SR. Read the documentation. But even if used like a separate pre-regulator, LM317 is superior too. May be even 2x pre-regulators will be audibly superior too. Just be careful with the cap in the LM317 (low ESR will kill the sound due to "oscillation")
Yes, it is in TAA 4/2000.
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I have no experience with LM440 so I don't have the answer. Why not just listen to the SR with and without the LM440? If the LM440 improved the sound I think no need to go overboard trying other solution hehehe.
If you want to go overboard I think you must modify the circuit a bit to ensure that the expensive but superior AD797 will be stable (but it may be unusable for other opamp).
@johnego I am using the board from the DIY Audio Store. I don’t think it would work without D5 in place. Then how can I listen without LM440? Are you referring to some additional extension?
The second part of your post is exactly what I inquired above. What changes do I need to make to the circuit to make AD797 stable? This would be a great help. Thank you!
The second part of your post is exactly what I inquired above. What changes do I need to make to the circuit to make AD797 stable? This would be a great help. Thank you!