How "super" is a Jung Super Regulator (or similar)?

[rock soderstrom]

Hi folks,

I recently looked around the web for alternatives to textbook LM7X15 regulator circuits. I found a few pages on this subject and I learned that the super regulators mentioned are all incredibly good on paper.

So my question is, why are these types of regulators so rarely used in ProAudio circuits?

Are the classic, integrated LM7X15 circuits simply good enough?

Wouldn't it be an advantage to use such super regulators in a mixer, for example, as a bipolar voltage source for the operational amplifiers?

Couldn't a 70dB microphone amplifier noticeably benefit from the super low noise values ​​or the very good PSRR values of these regulators?

What do you think?

Cheers

Source for PCB and some links with info and measurements:

https://diyaudiostore.com/products/super-regulator

 

[rock soderstrom]

A practical example: The linked power supply of this old Yamaha MC 2404 mixer should benefit a lot from such a super regulator. Right?

 

[Khron]

How sensitive is the supplied circuitry to power supply noise? Or in other words, how bad is the circuitry's PSRR?

You might be able to get away with a much simpler (and arguably cheaper) capacitance multiplier, perhaps. All bog-standard components, no risk of oscillation etc...

 

[Gus]

Test it.

It is so much easier to test things like this with DSOs they have dropped in price. Trigger on an input pulse look at the power supply nodes and channel outputs

Scope the power supply node when you send signals into the circuit .

Also look at a different channel output when you send signals into another channel.

Also you are often mixing channels so how much does it matter in different uses.

 

[JohnRoberts]

Hi folks,

I recently looked around the web for alternatives to textbook LM7X15 regulator circuits. I found a few pages on this subject and I learned that the super regulators mentioned are all incredibly good on paper.

So my question is, why are these types of regulators so rarely used in ProAudio circuits?

Are the classic, integrated LM7X15 circuits simply good enough?

Wouldn't it be an advantage to use such super regulators in a mixer, for example, as a bipolar voltage source for the operational amplifiers?

Couldn't a 70dB microphone amplifier noticeably benefit from the super low noise values ​​or the very good PSRR values of these regulators?

What do you think?

Cheers

Source for PCB and some links with info and measurements:

https://diyaudiostore.com/products/super-regulator

The question is not what the old PS looks like, but what is the PSRR (power supply rejection ratio) of the circuitry to be powered.

FWIW I have used truckloads of 78xx and 79xx VR.  I even remember using the old 723 VR before 78xx were available, but I'm old. One major 78/79 vendor while I was using truckloads at Peavey declined to guarantee a noise spec, so got voted off the island.

For TMI I discovered back in the 80s that you could improve the HF output impedance of typical 3 terminal VR by hanging a decent sized electrolytic capacitor across the output (1000 uF?). The 78xx VR use circa 741 opamp technology inside, so will exhibit rising output impedance with rising frequency due to diminishing gain bandwidth margin. The falling impedance (due to capcitance) complements the rising impedance of the active 3 term regulator to extend the low source impedance to safely above audio frequencies of interest.

For a wildly over designed VR here is the PS I provided for my last phono preamp to end all phono preamps (1980s).

I repeat this is overkill for any practical application, but that entire design was an exercise in engineering excess....

JR

 

[PRR]

> why are these types of regulators so rarely used in ProAudio circuits?

Hi-Fi stuff is sometimes more clever than solid, and is basically "one" signal. And small.

A 24-channel console with 124 amplifiers in it, the other channels are at least as much a corruption as the power. And a super-damping power box can't damp the rail 4 feet away.

Consoles typically have lots of local decoupling. If JR liked 1,000uFd on one regulator, what is the effect of fifty or a hundred 470uFd caps?

 

[Brian Roth]

> why are these types of regulators so rarely used in ProAudio circuits?


A 24-channel console with 124 amplifiers in it, the other channels are at least as much a corruption as the power. And a super-damping power box can't damp the rail 4 feet away.

Consoles typically have lots of local decoupling. If JR liked 1,000uFd on one regulator, what is the effect of fifty or a hundred 470uFd caps?

Trident  80 B/C consoles had a 470 uF cap across each rail on every module.  That would be up there at "fifty or a hundred"!  lol
The stock power supplies had a slow-ish "ramp up" because of the HUGE inrush current driving many dozens of 470 uF caps on each rail.

Bri

 

[ruffrecords]

Back in the 70s  every BA board in a module was decoupled with 100uF or so and evety compete module was decoupled with 1000uF. In fact there was so much capacitance across the power supply of a typical console  that the standard Coutant linear power supplies they used in those days could not cope with the inrush current. They went straight into foldback current limit. So they had to be specially modified to be able to supply enough short circuit current to charge the caps up to the full rail voltage.

Regarding the article, I am surprised they limited their comparisons to standard fixed and variable one chip regulators. At the time it was written the LM723 had been available for many years. It has all the components needed to make an excellent low noise regulator.

Cheers

Ian

 

[analogguru]

A pcb what they don't sell for a lot of money at the link above is this:
https://www.ebay.at/itm/62pcs-Capacitors-Array-Filter-Power-Supply-bare-PCB-for-amplifier-PSU-DIY/323633481322?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

I think this could be a cheap alternative to enter the audiophools world.....

 

[rock soderstrom]

First of all, I would like to thank you all for your answers.
I'll try to summarize that with my own words. Super regulators don't seem to be as easy to set up and operate as conventional LM7x15 power supplies. They seem to tend to oscillate with changing loads and are rather considered to be unnecessary. In one word - audiophoolery. 

@Khron

I hear you, you are right.

I am basically interested in this technique. The power supply of the Yamaha MC 2404 mixer was just an example I'm working on. Surprisingly, this mixer is not particularly noisy in its current state. It has a few other problems that need to be solved (general mushy sound, headroom, crosstalk and poor summing ;D). Since I'm changing parts of the power supply anyway (DC for VU lighting / LEDs), the idea was near to replace the main power supply with something better before I start to change caps and opamps. In this context, I also refer to Kingston's generally positive experiences with a super duper regulator in this thread:

https://groupdiy.com/index.php?topic=37307.80

For those who are interested, I attach the relevant circuit diagrams of the mixer.

@ Gus

I will test it.

@ JR and PRR

As for local filtering and buffering, I think the Yamaha mixer could use a little more, right? I don't want to go crazy with the capacitors, but I think I have to replace a few anyway.

@  analogguru

Cool stuff  ;D Years ago I saw a HIFI stereo preamplifier with over 50000uF, nicely distributed on countless small capacitors. The whole case was full of it. Looks great, somehow military. LOL

 

[JohnRoberts]

First of all, I would like to thank you all for your answers.
I'll try to summarize that with my own words. Super regulators don't seem to be as easy to set up and operate as conventional LM7x15 power supplies. They seem to tend to oscillate with changing loads and are rather considered to be unnecessary. In one word - audiophoolery. 

@Khron

I hear you, you are right.

I am basically interested in this technique. The power supply of the Yamaha MC 2404 mixer was just an example I'm working on. Surprisingly, this mixer is not particularly noisy in its current state. It has a few other problems that need to be solved (general mushy sound, headroom, crosstalk and poor summing ;D). Since I'm changing parts of the power supply anyway (DC for VU lighting / LEDs), the idea was near to replace the main power supply with something better before I start to change caps and opamps. In this context, I also refer to Kingston's generally positive experiences with a super duper regulator in this thread:

https://groupdiy.com/index.php?topic=37307.80

For those who are interested, I attach the relevant circuit diagrams of the mixer.

@ Gus

I will test it.

@ JR and PRR

As for local filtering and buffering, I think the Yamaha mixer could use a little more, right? I don't want to go crazy with the capacitors, but I think I have to replace a few anyway.

second guessing Yamaha's design skills may not be productive.

JR

@  analogguru

Cool stuff  ;D Years ago I saw a HIFI stereo preamplifier with over 50000uF, nicely distributed on countless small capacitors. The whole case was full of it. Looks great, somehow military. LOL

 

[rock soderstrom]

second guessing Yamaha's design skills may not be productive.

JR

;D but the Yammy Mixer was cheap, I got it for 130€. Good enough (after some hot rodding) for my new home studio.

Here is a stitched jpeg of the schematics. Sorry for the poor quality. The PDF is protected, I had to use screen copies.

 

[PRR]

> one word - audiophoolery. 

You are thinking out of context. Jung's work is quite valid, for stuff like a stereo preamp or CD player audio. It may not extend to LARGE systems, not without putting a Jung on every stage.

'723 was a good regulator but the Zener was not the quietest baby in the manger, and the opamp could be quieter and faster. Jung penciled and trialed many references and opamps, and studied response well past the audio band where a '723 typically looks like a coil.

 

[rock soderstrom]

> one word - audiophoolery. 

You are thinking out of context.

No, that is not correct. My answer was ironic* feedback on analogguru's post:"I think this could be a cheap alternative to enter the audiophools world....." Please note the winking smiley.

I would not deal with this topic if I thought it was audiophoolery. Thank you for your contribution and the reference to problem areas of this technique. This type of qualitative answer was the reason to ask this question here...I am still reading on topic and I will build up such a PCB just to test it in something more suitable like a headphone amp or micpreamp. I am still curious.

Cheers


* Maybe my irony was lost somewhere in translation.

 

[ruffrecords]

'723 was a good regulator but the Zener was not the quietest baby in the manger,

Indeed,  but its output is directly available and simple means of filtering it are well documented.

Cheers

Ian

 

[peranders]

The super regulator has excellent PSSR properties and a very low noise if you choose the right opamp but you could also use LT3045 which has similar properties although a bit slower and sadly a very un-DIY friendly physical size.

Here you have a LT3045 based power supply.
https://www.mpaudio.net/product-page/sd-hpuln-ps

 

[JohnRoberts]

The super regulator has excellent PSSR properties and a very low noise if you choose the right opamp but you could also use LT3045 which has similar properties although a bit slower and sadly a very un-DIY friendly physical size.

Here you have a LT3045 based power supply.
https://www.mpaudio.net/product-page/sd-hpuln-ps

That is pretty impressive low noise, my better than needed PS has probably single digit uV noise. That number could be improved by using a different op amp than the TL072 in my design, but most decent audio circuits will exhibit several tens of dB power supply rejection making this noise less significant.

JR

 

[abbey road d enfer]

The super regulator has excellent PSSR properties and a very low noise if you choose the right opamp but you could also use LT3045 which has similar properties although a bit slower and sadly a very un-DIY friendly physical size.

Here you have a LT3045 based power supply.
https://www.mpaudio.net/product-page/sd-hpuln-ps

Whatever the noise performance of the regulator, it won't replace the local decoupling that provides the last dB's of noise filtering.
All my designs are based on loose power rails and local decoupling. I distribute power via resistors, typically 22-47 ohms for each PCB area containing correlated stages, so there is no interference between sections and no glitch is transmitted to the PSU.
Early in my carrier I learnt the hard way that having regulators on each channel of a mixer is a source of longitudinal noise.
In particular the 78/79xx create a noise current loop that is very difficult to isolate from the rest of the circuit. LM117/317 are much quieter.
I've never been convinced by the comparisons between good standard regulators (I exclude the 78/79xx) vs. super LN regs, because the circuits they were applied to required to have a flaw in order to show significant difference, usually lack of local decoupling, or interference betweeen ground currents and signal lines (poor design).

 

[peranders]

The advantage of a super regulator is that the output impedance in the audio range is much lower than what a "normal" decoupling cap can create.

 

[abbey road d enfer]

The advantage of a super regulator is that the output impedance in the audio range is much lower than what a "normal" decoupling cap can create.

Is that important? As I said, I like sloppy rails. I know how capacitors react to sollicitations. I use coupling capacitors, so having decoupling capacitors doesn't change significantly the operation.
These "super-duper" regs, they just propagate disturbances back to the PSU, instead of keeping them confined to a controllable area.