PS Audio PowerPlant 12 Review (AC Regenerator)

[captainbeefheart]

I guess you've figured it out that I was the one who sent in the P12 to be tested. There were some power issues I had causing some weird feedback/noise that the P12 did help eliminate (maybe an off-label use, I don't know). Somewhere in my post history on one of these threads is a recording of the noise with my amp cranked to 11. From a quality standpoint, I don't think it makes me hear things in my music that wasn't there before. Honestly I found the biggest thing that makes my system sound better is my mood. A good mood makes music sound better than any device could possibly do.

My initial motivation was to see if maybe power was the cause of my noise issues. My house (and wiring) are old. I was also interested to see if perhaps it could help. The audio dealer where I bought my amp had a puritian conditioner he was showing me. We didn't listen to it, but he did have some little device that, when plugged into the wall, would make the noise in the power "audible" via a little speaker and he showed me the wall vs the puritan, and the puritan made the device make no sound at all. I thought maybe there is something to power conditioning. I saw the PS audio and thought their approach of "regeneration" was worth looking into.

I think what PS Audio charges new for the P12 is too high a price for what the thing does. I understand it is a niche device so they have to make their money back somehow since there are some expensive parts in it. I found a really good deal on a secondhand unit that looks essentially new to me. They offered a 30 day trial and I though $60 for shipping back if I don't like it would be worth my while. I ended up liking it enough to keep it.

My motivation for having it tested was that I found this website when looking for something else and I noticed the P12 (or any regnerator) wasn't tested. I figured I could use that $60 in shipping to test it for the world. I didn't really care about the outcome since I was already happy with my purchase, but the results were interesting and this discussion has been well worth it to me!

So in your case the P12 did improve the issue you were having with your system which I think is a win regardless if it could have been resolved in a different manner. I have no reason to think you are lying so we can mark a positive attribute for the P12 in that it can in fact help with certain problems whether they are ground loop related or possibly some other issue.

Hopefully you don't mind if I ask a few questions. If not just ignore me as you have zero obligation to satisfy my curiosity.

What amplifier had the feedback/noise issue? I have a lot of experience with commercial products up to high end less common audio products in both design and repair aspect. I may just be familiar with your specific amplifier or at least look at the schematic and see what's going on.
What speakers were you using?

What measure first did you try to remove the feedback/noise? For example did all amps you have do this? Did you try the amp from a different branch power circuit in your houses or a different home on a different grid or a standby generator etc.. Did you try plugging all devices into the same receptacle via power strip? Did you try passive/active DI (direct inject) boxes or audio grade signal isolation transformers? You get the idea.

I am just trying to paint a bigger picture in order to deduce possibly what was going on with your system and then possibly how the P12 corrected the issue. If we can track down the issue and the solution is inexpensive you may prefer to even sell the P12 and get your money back while using the other solution to solve the feedback/noise problem. The majority of times people have noise problems that ask for my assistance I need to figure out if something is defective or if it's just some ground loop noise related problem. I have seen people with other appliances on the same branch circuit that will pollute the branch with noise and effect system performance by audible noise. Other times I have heard the problem and immediately said the amp needs to come with me it needs repair. Whether it's 120Hz power supply noise from bad filters in the amp, 60Hz internal ground loops can even be lowered or with tube amps hum balance pots can be adjusted to reduce noise, feedback squeals are a stability problem where the amp either has parts that have drifted and or deteriorated in performance enough to cause the instability and I have even seen some amps come straight from the store brand new but wasn't designed great and rigorously tested with actual reactive loads to see if it remains stable. You'd be surprised how many just test on a purely resistive load and think all is well when our speakers are anything but purely resistive load especially Electrostatic speakers like Magnepan, I have seen them send an amplifiers into oscillation and end with fireworks that had poor phase margin.

Thanks for letting Amir test your gear and letting us gab about it endlessly especially where many including myself are talking so horribly about PSAudio and their products.

 

[MakeMineVinyl]

Just to illustrate a situation where a mysterious noise enters a system: This week I purchased a Pro-Ject Phono Box RS2 as part of a re-vamp of my vinyl playback chain (part of this project was also wall mounting my turntable so that it will play nice being in the same room with four 18" subwoofers ) .

The RS2 has two outputs, one balanced which goes to my preamp and the other unbalanced which goes to my patch bay so I can digitize vinyl if the urge hits. I use a Focusrite Scarlett 4i4 USB interface to do this.

The problem which took me awhile to solve is that there was a 'digital sounding' squeal which sounded like clocking leakage of some sort coming from the RS2. My first thought was that somehow the unit had a defect since it does have some digital control circuitry and a microcontroller inside, and I'd have to contact the seller for a possible exchange.

I went back and forth trying to isolate the source of this noise. I then I finally turned off the RS2 and the noise was still there. WTF? Then I looked at the patch bay, I saw that the unbalanced output of the RS2 was patched into the Focusrite Scarlett 4i4 interface; I unplugged the patch cords and the noise went away. WTF indeed.

I have no idea what could possibly be the mechanism for provoking this noise, and honestly I don't know if I have enough intellectual curiosity to search for the reason, but we'll see. I'll probably insert some audio isolation transformers going to the Scarlett 4i4 for a permanent cure if that works - I use transformers on the input of my active crossover to solve a ground loop problem (remember, I have extremely sensitive speakers with 107db/w in the HF). Neither the RS2 nor the Scarlett 4i4 have any problem by themselves when not hooked together.

But I don't find it too hard to imagine that somebody might resort to using a AC power line regenerator to try to cure this kind of problem - and it might just work. Who the hell knows?

 

[captainbeefheart]

I have no idea what could possibly be the mechanism for provoking this noise, and honestly I don't know if I have enough intellectual curiosity to search for the reason, but we'll see.

My guess is you have the Scarlett 4i4 plugged into a computer? I believe that's how they get power is from your computer correct? The RS2 takes power from the wall via an external 20v power supply. The RS2 must have it's output grounds tied together and even with the RS2's power is off there the noise currents must be passing through the shared ground at the output of the RS2 between the Scarlett and the input of the preamp.

Easy enough to test, with the RS2 off probe signal ground on the balanced output and see if there is continuity between it and the ground sleeve on the unbalanced RCA output. This will put the Scarlett directly connected to the input of the preamp.

 

[bambadoo]

Crap, it should have an audiophile fuse to work better.
Of course this is Ted Denney´s facebook group. Total freakshow there.

 

[Ricardus]

 

[srkbear]

Crap, it should have an audiophile fuse to work better.
Of course this is Ted Denney´s facebook group. Total freakshow there. View attachment 201814

Amir facetiously invoked such a concept in his review of the MHDT Pagoda—the fuse had a different color on each side. He mused aloud whether it might be one of those directional audiophile fuses?

 

[captainbeefheart]

I would love for Amir to reverse engineer these things while he has them but I understand that would take a lot of time. I don't think Amir is anywhere near where I am but I would offer up my services to reverse engineer anything the forum would want to dive deeper into.

Take the P12, they claim the output is a "perfect wave" yet it had the same exact profile as the mains. This tells me they aren't even using something simple like a 555 IC to make the new sine wave but instead are simply sampling the mains frequency through say a divider and then sending it through a power amplifier with feedback based limiter/compressor to keep the output voltage constant under different loads. I just cannot fathom the point of this thing having the same exact profile as the mains, if the device does what they advertise it to do the output should be a perfect spike at 60Hz on an FFT plot and nothing else. Amir gave us a big clue making the connection between the output profile of the P12 vs the mains profile. Something doesn't smell right in Denmark.

I cannot even do the technical discussions anymore about certain things like audiophile fuses, it's just absolutely ridiculous. Some of these fuses are more expensive than my DAC!!!! Ya I know I probably need to upgrade my DAC but for me the Topping D10s works just fine and I am happy with it. I noticed inside has sockets for the IC's, I was very surprised to see this, has anyone swapped IC's and if yes what did you replace the originals with and what where your opinions about before/after?

 

[solderdude]

It is known/described how the P12 works.

Mains is not regenerated in this model (was in older models) but filtered and 'repaired'.
The output is stabilized.

And indeed they aren't using a 555 to make the new sine wave. They sync mains, create a new (clean) AC using a regular DAC chip which is used as a reference. That reference waveform can even be manipulated to a certain extend. The voltage difference (shape and amplitude) between mains input and desired output voltage (reference) is fed to an amplifier that is in series with the (filtered) incoming mains which provides the needed correction voltage.

So output = mains input + correction and is based on (compared to) a synchronized to mains newly generated reference voltage.

It is not a completely regenerated output voltage.

 

[captainbeefheart]

It is known/described how the P12 works.

Mains is not regenerated in this model (was in older models) but filtered and 'repaired'.
The output is stabilized.

And indeed they aren't using a 555 to make the new sine wave. They sync mains, create a new (clean) AC using a regular DAC chip which is used as a reference. That reference waveform can even be manipulated to a certain extend. The voltage difference (shape and amplitude) between mains input and desired output voltage (reference) is fed to an amplifier that is in series with the (filtered) incoming mains which provides the needed correction voltage.

So output = mains input + correction and is based on (compared to) a synchronized to mains newly generated reference voltage.

It is not a completely regenerated output voltage.

That explains a lot thank you!

I thought at least the fully regenerated older model types were at least going to give you something that may justify spending this much money, I personally do not think it's necessary unless you live in a place where your power is truly horrendous. Why would they switch to this design when the output is not really any better except for the fact you have a more consistent output amplitude which I don't really consider beneficial due to the fact we design power supplies to deal with mains fluctuations already via regulated DC supplies inside the amp.

I would love to be a fly on the all during the design of these products. What on earth are they sitting down trying to accomplish and why don't they understand how pointless this product is? Especially with switching supplies that accept a very wide range of input voltages. Maybe I am missing something, I'll have to go back and read more about it and watch Amirs review again because from memory I thought the output wasn't any cleaner than the input.

 

[captainbeefheart]

I went back to go through the tests again and sorry made a mistake, the distortion is lower but noise increased which is what I thought the point of this device was, to clean up noise from the mains not just distortion? It actually increased noise and created 60Hz ground loops lol. So while it may solve a ground loop for you it also may create one, great.

This goes back to my original assessment that most of the nasty stuff is going to be created inside your device from it's own rectification which is after the mains or regenerator so it's pointless. Like I said, you could have an absolutely perfect 60Hz sine wave transmission from your mains or whatever, distortion and noise below -115db for example and it's moot because the instant it hits the rectifier under load inside your device that's where the nasty business happens and so we clean up and filter AFTER the rectifier, then further regulate if need be. As the tests prove any device plugged into the P12 never shows any improvement of it's noise floor or any other measurement. Pointless headless panther I say.

 

[srkbear]

I went back to go through the tests again and sorry made a mistake, the distortion is lower but noise increased which is what I thought the point of this device was, to clean up noise from the mains not just distortion? It actually increased noise and created 60Hz ground loops lol. So while it may solve a ground loop for you it also may create one, great.

This goes back to my original assessment that most of the nasty stuff is going to be created inside your device from it's own rectification which is after the mains or regenerator so it's pointless. Like I said, you could have an absolutely perfect sine wave transmission for your mains or whatever, distortion and noise below -115db for example and it's moot because the instant it hits the rectifier under load inside your device that's where the nasty business happens and so we clean up and filter AFTER the rectifier, then further regulate if need be. As the tests prove any device plugged into the P12 never shows any improvement of it's noise floor or any other measurement. Pointless headless panther I say.

This most recent discussion is admittedly way above the wattage supply above my neck. But it just seems most logical to me that the control of noise should be the prerogative of the power supply design in the amp itself, and consequently, the more electronic junk I put in between that and the wall, the more stressors I’m contributing to that job. And after reading dozens of measurements on this forum and elsewhere, if noise were a common occurrence in well-made audio gear, shouldn’t we be seeing evidence of it in those graphs?

I guess the question would be if this “power conditioner” could clean up noise emitted from crappy amps. But that seems to me a teleological argument—why buy a $6,000 mop when you can just buy an amp that doesn’t spill? Am I oversimplifying this issue?

 

[captainbeefheart]

......, if noise were a common occurrence in well-made audio gear, shouldn’t we be seeing evidence of it in those graphs?

Yes exactly. For example many of the tube amplifiers tested here like the VTA ST70 you'll see the 120Hz power supply product at the output which is what gives them the poor SINAD score. This is mostly due to the fact these amps use tube rectifiers which are limited by their repetitive peak forward current ratings to take advantage of extra filtering in the power supply. Many that use solid state rectifier still don't make clean power supplies and combined with circuits that have poor PSRR you get high noise floor at the output.

I guess the question would be if this “power conditioner” could clean up noise emitted from crappy amps. But that seems to me a teleological argument—why buy a $6,000 mop when you can just buy an amp that doesn’t spill? Am I oversimplifying this issue?

Nope that's not an oversimplification, good equipment should be designed to run directly from mains and still have a low noise floor. It's not impossible and you do not need a power "conditioner", mains shampoo is just fine.

 

[srkbear]

Yes exactly. For example many of the tube amplifiers tested here like the VTA ST70 you'll see the 120Hz power supply product at the output which is what gives them the poor SINAD score. This is mostly due to the fact these amps use tube rectifiers which are limited by their repetitive peak forward current ratings to take advantage of extra filtering in the power supply. Many that use solid state rectifier still don't make clean power supplies and combined with circuits that have poor PSRR you get high noise floor at the output.



Nope that's not an oversimplification, good equipment should be designed to run directly from mains and still have a low noise floor. It's not impossible and you do not need a power "conditioner", mains shampoo is just fine.

Thank you! Just so I make sure I’m reading you correctly, for the VTA the tubes are functionally part of the power supply, or is the SINAD measured after the tube stage is intercalated after the power supply’s APFs and voltage regulators? And is the 120 hz current the product of DC conversion from the 60 hz AC coming from the wall? And if this isn’t one question too many, why is such a frequency doubling of the sine wave necessary?

I occasionally build vintage Fender Tweed amp repros, and I’ve since I follow schematics without deep diving into the EE, these are questions of interest to me, thanks!

 

[DonH56]

Thank you! Just so I make sure I’m reading you correctly, for the VTA the tubes are functionally part of the power supply, or is the SINAD measured after the tube stage is intercalated after the power supply’s APFs and voltage regulators? And is the 120 hz current the product of DC conversion from the 60 hz AC coming from the wall? And if this isn’t one question too many, why is such a frequency doubling of the sine wave necessary?

I occasionally build vintage Fender Tweed amp repros, and I’ve since I follow schematics without deep diving into the EE, these are questions of interest to me, thanks!

One of a myriad of explanations of how a full-wave rectifier works -- notice the output frequency is doubled before filtering. Each "half" of the 60 Hz cycle is converted (rectified) to quasi-DC, doubling the frequency, then filter capacitors smooth the signal to provide an essentially constant DC voltage to power the circuits.

Full Wave Rectifier - Definition, Circuit Construction, Working, Advantages

A full wave rectifier converts the complete cycle of alternating current into a direct current. Learn its definition, formulas, construction and frequently asked questions here

byjus.com

In many tube amplifiers, the diodes D1 and D2 are actually tubes as well.

HTH - Don

 

[srkbear]

One of a myriad of explanations of how a full-wave rectifier works -- notice the output frequency is doubled before filtering. Each "half" of the 60 Hz cycle is converted (rectified) to quasi-DC, doubling the frequency, then filter capacitors smooth the signal to provide an essentially constant DC voltage to power the circuits.

Full Wave Rectifier - Definition, Circuit Construction, Working, Advantages

A full wave rectifier converts the complete cycle of alternating current into a direct current. Learn its definition, formulas, construction and frequently asked questions here

byjus.com

In many tube amplifiers, the diodes D1 and D2 are actually tubes as well.

HTH - Don

It certainly does, much appreciated! Yes, the one bit of tech I did thankfully learn before starting was not to crispy critter myself by touching the filter caps before discharging them. But I unfortunately do have my share of soldering iron scars.

I’ll get to reading this right away—appreciate the link. Cheers

 

[captainbeefheart]

Thank you! Just so I make sure I’m reading you correctly, for the VTA the tubes are functionally part of the power supply, or is the SINAD measured after the tube stage is intercalated after the power supply’s APFs and voltage regulators? And is the 120 hz current the product of DC conversion from the 60 hz AC coming from the wall? And if this isn’t one question too many, why is such a frequency doubling of the sine wave necessary?

I occasionally build vintage Fender Tweed amp repros, and I’ve since I follow schematics without deep diving into the EE, these are questions of interest to me, thanks!

The VTA has zero voltage regulation inside, it's just a full wave rectifier with simple pi filters.

One of the tubes is functionally part of the power supply, it has two diodes inside one bottle. The full wave rectifier doubles mains frequency and is chosen because it's essentially conducting current into the load and supply capacitors every 8mS instead of 16mS and the filters are at half the impedance they would be with a half wave rectifier so they filter better given same value of reactance. Half wave you are just conducting the positive cycle of the 60Hz sine wave which takes 16mS between each current pulse.

 

[captainbeefheart]

@srkbear

That link provided by @DonH56 shows how a center tapped full wave circuit would work to create charge cycles every 8mS or 120Hz. Here is an image of a full wave bridge rectifier showing each cycle's current flow through the diodes to give the same charge pulses every 8mS or 120Hz. There are differences for each type in regard to voltage and current outputs. Basically for center tapped full wave you get .7x the AC secondary voltage for DC voltage and 1x the secondary AC current rating. So you get to use the whole current rating of the secondary of the power transformer so nothing to worry about. BUT, with a full wave bridge rectifier since you are getting 1.4x the secondary AC voltage for your DC voltage, you can now only use .65x the secondary winding AC current. Think of it this way, for a bridge the whole secondary winding is passing current every half cycle where the center tapped full wave has current flowing in one half the winding in the first half cycle and then switches to the other half of the winding the other half cycle. So the you can see how there needs to be a reduction of current in a bridge rectifier to stay within the average VA or wattage rating of the winding. The center tapped full wave has half of it's winding conducting every 16mS instead of every 8mS like the bridge, therefore you can use the entire current rating of the secondary because the winding has double the time to cool down between conduction cycles.

 

[captainbeefheart]

For all you hobbyists out there building stuff here is a great rectifier design reference to keep in your files. I have most of it memorized at this point and forgot about it but wanted to post for anyone else that may find it useful. I know a very long time ago when I was getting into designing power supplies I found having a "cheat sheet" on each rectification method and sizing the transformer secondary AC voltage and current ratings in relation to the DC output voltage and load current. Mind you the secondary AC current includes charge current for the filters + load.

http://hammondmfg.com/pdf/5c007.pdf

 

[solderdude]

Why would they switch to this design

Heat, longevity, weight, production costs.

What on earth are they sitting down trying to accomplish

Paul 'heard' everything sounds 'better' when it is used and even picture 'cleans' up in video.
PS Audio is targeted to people that believe 'everything' makes a difference and that they (PS Audio) poses the knowledge how to achieve this.
They also sell a lot of those power plants and make money of it.
Regardless if PS Audio believes it themselves, their customers do which is half the battle.

There will certainly be real world cases where it actually solves a problem and there will be plenty more cases where owners believe they actually get better sound. Win-win in both situations.

There are other 'conditioners' around as well but these look better and when your favorite manufacturer tells you it is better they will buy it when funds permit.

 

[srkbear]

Heat, longevity, weight, production costs.


Paul 'heard' everything sounds 'better' when it is used and even picture 'cleans' up in video.
PS Audio is targeted to people that believe 'everything' makes a difference and that they (PS Audio) poses the knowledge how to achieve this.
They also sell a lot of those power plants and make money of it.
Regardless if PS Audio believes it themselves, their customers do which is half the battle.

There will certainly be real world cases where it actually solves a problem and there will be plenty more cases where owners believe they actually get better sound. Win-win in both situations.

There are other 'conditioners' around as well but these look better and when your favorite manufacturer tells you it is better they will buy it when funds permit.

I’m not sure whether there are any consumer grade applications for these power conditioners (excluding surge protectors), but I can certainly relate to its appeal based on my own journey with this hobby.

Before I had spent much time on this site, I had purchased an iFi Pro iCAN Signature for my headphone setup, along with several other of iFi’s offerings. It had certainly gotten raves over at Head-Fi, along with the salient (corporate-funded) audiophile websites around. I was really happy with it and still am. But once I became invested in their brand, I did a deeper dive into their accessories and gave in to an iFi Power Station ($599), a power strip that purports to have active noise cancellation circuitry and a number of likely redundant stages of passive filtering for each of its eight power outlets—promising an array of sonic improvements.

The thing reeks of heft and quality. And having this statement piece anchoring my gear provided me with a sense of authenticity as an “Audiophile”, before I had even considered whether noise was an issue for me. IFi seemed pretty sure it was there though, despite the fact that we had purchased our home brand new, and I knew its build quality included a fastidious investment in sound electrical wiring.

But that didn’t occur to me or factor into my purchase decision at the time at all—I was relatively new to this hobby, and in my inexperience I didn’t trust my ears to detect noise, nor had I sufficiently digested the principles evident on this site’s reviews. Given how much I had invested in my setup already, I was obsessed with FOMO, susceptible to any claims offering to make my already formidable investment sound even “better”—better cables, connectors, power supplies, and conditioners such as this one. It was an obsessive, exhausting quest without any definable endpoint.

Then after some time on this site, someone here took me to task on an expensive digital cable, and I felt crummy enough trying to defend it that I chose to bow to their reason and return it for a serviceable one at a fraction of the price. Admittedly it bugged me for awhile. But after spending a year or so immersing myself in the spectrum of opinions here, I gradually got deprogrammed from the elitist platitudes on Head-Fi and leaned into my own reason-based training as a scientist in another field. And not only has this saved me a ton of money, it’s freed me up to enjoy my music instead of listening for illusory imperfections in my system.

The term “audiophile” has been appropriated by so many bad actors that it has not only become pretentious, but arguably meaningless. For those who haven’t done the work to confidently earn it, buying it has become a facile choice. And when music is exploited for status-seeking tastes, this is how predators such as PS Audio can successfully turn outlandish profits, producing little black boxes that offer fantastical promises that cannot be refuted.