Getting it straight

January 24, 2023
 by Paul McGowan

It doesn’t take long to figure out the importance of AC power, and perhaps no device can better demonstrate the advantages of perfect AC than a Power Plant.

I wonder how many of the thousands of Power Plant owners across the globe really understand what’s important in power—why their AC regenerators make such a huge improvement to the sound of their system.

Is it clean power? After all, Power Plants lower distortion by several magnitudes: 2% to 5% THD becomes 0.2% THD. That’s not nuthin’.

Or is it perhaps something else?

It is the something else I’d like to focus on.

Back in the 1990s, when I started working on the problems of AC power, the focus was twofold: cleaning up the AC line noise and doing so without adding much in the way of impedance.

When the first waves of line conditioners and cleaner-upper AC filters hit the market, we could hear what we thought was better sound—certainly cleaner sound. Over time we felt the music had been cleaned too much—stripped of more than just noise—there was an unwelcome sterility to what we were hearing. That’s when we realized the filter’s increase in impedance was wreaking sonic havoc.

We had known for many years that lowering impedance dramatically impacted sound quality, but until those line filters came out, we’d never really put two and two together. The more we played and experimented, the more we became convinced that the lower the impedance the better the sound—to the point where we stopped worrying about removing unwanted AC noise.

That’s when the idea of the Power Plant AC regenerator surfaced. A well-designed regenerator regulated the AC power. What’s that mean? Regulation means that regardless of the power demanded by the connected audio equipment, the output AC voltage would never vary. A steady 120/230 volts regardless of demand—something that simply does not happen when you power equipment straight from the wall—and something made much worse by the insertion of an AC filter.

Not so coincidently, the act of voltage regulation proportionally lowers impedance: the tighter the regulation, the lower the impedance.

Regulating the AC power to a few millivolts of change regardless of the demand from your equipment is the key to the Power Plant’s success and why no equipment in the stereo chain—in particular power amplifiers—should be powered directly from the wall.

Cleaning the noise from the AC line? Turns out not to be so important.

It’s all about the regulation.

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29 comments on “Getting it straight”

  1. Keeping any kind of environment HF out of the power cirquit (cabling AND power plant) also seems to be a meaningful measure still to address. It gets obvious when comparing a non HF protected supply with regenerator (or conditioner) vs. a HF protected without.

      1. I have M700 amplifiers that I have tried on every zone of my P12 and they still sound much better plugged into the wall. My DMP and Gain Cell Dac sound much better plugged into my P12. This should not be the case. What am I doing wrong?

          1. I have used the high current and other zones at different times.
            When I plug into the wall, the sound has more presence. More like the artists are in the room.
            When I plug into the P12, The sound is more “dull” sounding.
            Do you have a preferred way of plugging in the M700’s?

      2. Did you ever try, how much and which effect the impedance effect and how much the rest of the regulation makes? Are they separate measures or tightly connected?

  2. For many people today’s audio issues are very different to what they were in the 1990s. The problem goes beyond that. I use a mains distributor by a company that started making power regulation products in the early 1960s, and still does. Our main hi-end brand, Naim, have been providing external high quality 24v DC supplies since the 1980s, as does my phono stage from Poland. It was a big surprise to me that the Stellar Phono did not have an external DC supply. So whilst the regenerator is a one-size-fits-all, over here many companies address power issues for their specific products.

    The first question is whether voltage regulation and impedance are important, and for my electronics they are irrelevant. It can run on any voltage and draws hardly any power, but it does benefit from lower noise. Today’s components generate a lot of noise and a key factor is to isolate them.

    Whilst Naim can happily be plugged into the wall, there are a wide range of solutions depending on the component and the operating environment. I use a conditioner and two 24v DC supplies. One of my more important components is a fibre media converter and is powered by a rechargeable 6-9v battery, the supply has two batteries that switch between supplying power and charging.

    I’ve used a regenerator, to me it has certain applications, but in other situations it is a sledgehammer when a $500 filter with component isolation and surge protection is just fine.

  3. I have used PS Audio power regenerators that regulate the AC power since the days of the P300. Today I use a P15. I have always been pleased with the results.

  4. I use the P-15 advantageously in one of my audio systems. I would not say it makes a “huge improvement” to the sound of my system. It is a subtle improvement, most noticeable in reverb tails and separation of notes in complex passages. In my system the sound improvement is like going from a good-sounding interconnect to a best-sounding interconnect. It is significant enough for me to keep my P-15, but not everyone would hear the difference. The quality of the existing power, the type of music played and the sensitivity of the listener’s ear to subtle nuances are factors in how much a PowerPlant is appreciated. I recommend everyone with the funds at least try a regenerator like the P-15 and judge for themselves how much improvement they hear in their system.

    1. I think the first thing to do is check your power. I have two feeds to my audio, on different supplies. The circuit impedances per the electrical certificate are 0.18 and 0.20 ohms. According to Stereophile, the output impedance of the P15 is about 0.10 ohm and the P20 about 0.05 ohm. At other points in the house, such as the loft, using different and longer wire, I get 1.61 ohm impedance. My audio is only about 4m from the consumer unit and the 100A supplies, hence the much lower impedance.

      So using my figures, if like someone I know who has his stereo in his loft, he could reduce impedance by 1.4 ohms or more just by moving the stereo closer to incoming mains, or running a thicker mains feed upstairs. Is spending $10,000 on a regenerator to reduce my impedance by 0.1 ohm going to make any difference? My all-in-one system cost about that much, so it’s a pretty expensive thing to do on a hunch.

      I’m as guilty as the next person, but I wonder how many people have actually first considered the quality of and potential to improve their incoming mains? I did it two years ago, as much out of necessity. This involved digging up the street and installing a new cable the size of your arm, but the invoice from the utility company was less than the cost of a P5.

      The problem with this approach it usually has to be done at the construction stage, but from what I read many people do go to the effort to get a good supply and low impedance wiring to their audio.

      1. Steven, I have no idea how good or bad the mains power is in England and what it is like to have 230 V be the standard voltage from the mains. He were I live ( 30 miles north of NYC ) I get my electrical power comes from this lovely company Con Ed. They supply some of the worst power ( if not the worst power ) in the US.

        Taking any part of my system of of the PS Audio power regeneration is very noticeable.

        I have recommended PS power regeneration to three fellow audiophiles who also get their power from Con Ed They have all said they were grateful for the improvement that it made in their SQ.

        1. It seems to me, the US power supply is indeed much worse than the one of many other countries, especially those with 230V. Could be many users in the US benefit much more from power plants than others…but the impedance aspect should always help I guess.

      2. Steven, not being that wealthy, I probably would not pay $10K for a regenerator. I paid $5K for the P15 during PS Audio’s sale. Everyone can theorize on whether a regenerator would make a positive difference, but because there are so many system variables, the only way to tell is to actually try one in your system. It is much easier for those of us in the U.S., where we can easily return it if we don’t hear an improvement. One more thing, the power cable used from the wall outlet to the regenerator is also probably important. One reviewer (Bacon) claimed to hear an improvement in the PowerPlant when he used a certain Synergistic power cable, the same cable used for the Synergistic power conditioner that he reviewed along with a P10.

        1. I think the point is that, it’s not, as Paul suggests, “all about regulation”, it’s as much about:
          – the quality of your incoming power
          – the specification of your supply (I have 100A of 230v dedicated for my stereo)
          – the quality of your domestic wiring
          – whether impedance is important to your hifi
          – whether voltage stability is important to your hifi
          – whether noise is important to your hifi

          With my system a fairly cheap conditioner does all I could need and if I had BHK amplifiers they would be plugged into the wall, because there is ample current, stable voltage and low impedance.

          So I beg to differ with Paul, there seem to be many different valid approaches to power, depending on the circumstances, including hifi with dedicated DC supplies.

          1. Steven, To put this in perspective you have at 230V 100A service just for your stereo system. In the US most single family houses have a 120V 200A service for the entire house! 😮

        2. I purchased the recommended, AudioQuest, 1 meter, 20 Amp cable for between the wall & my P20. In case I ever have 230 volts access; AudioQuest told me that the cable is the same at that used for the standard, 110 volt cable, with the different ends plugged into the appropriate back ports of the P20. Plugging the, 20 Amp cable, into the, `left power input of the P20,’ is supposed to work if the cable is plugged into a 110 volt wall outlet. The P20. `knows,’ that it can only draw up to 15 amps ~ The 20A, one meter cable, through PS Audio, cost $900; may be a bit more, now.

  5. I would suggest that people actually measure their AC line for impedance/ voltage drop issues with their system. Make sure you have a decent DMM like a Fluke. Plug the meter into the AC line feeding your system, and then play some music with a ton of bass energy (like electronic dance music with powerful bass pulses) at the highest level you would ever play. Take a look at the AC voltage level. Is it varying significantly? If so, perhaps a low impedance voltage regulation device like a PowerPlant is worth it to try. If you do not see significant voltage drops, then perhaps a PowerPlant would be overkill in your set up.
    I have been surprised at my house, that the AC line voltage remains steady even at very high levels-but I do have the advantage that the line transformer feeding my home is not shared with any other users.

    1. The combined weight of a 600w mono-block plus P15 would break my ancient back. It would be over 200 lbs. There’s no way I could move that around without a fork lift. You’d need to reduce the weight substantially for it to work for me.

      1. To really break your back, try moving TWO monoblocks and a P20 all at the same time. LOL Obviously you should move them individually. Get creative. Unload each from its box onto a small rug, blanket or towel that you can drag around. Then at the final location you only have to lift them at one end an inch or so to slide the rug, blanket or towel out from under them. Wait at least six months after hernia surgery. And don’t forget to bend your knees as you lift. LOL

        1. Some people like monster trucks and others crave the Peel P50.

          Personally, my hifi is in a single stack unit on wheels and if needed I can lift it up with one hand, including the high mass turnable sitting on top. I do wonder what proportion of hifi consumers under age 60 have an interest in monster truck audio.

  6. Paul convinced me that the P20 would improve on the already stellar results of my P10. He was correct of course. My amp is a Conrad-Johnson ART150, which is all tube. What is most amazing is that the amp is stable no matter what is happening with the AC line, which in Florida can vary dramatically because of the preponderance of AC usage and fluctuations in daily demand particularly during peak usage times. Bias of the output tubes is a set it once and forget it affair using the P20. Without it, bias LEDs would be blinking on and off all the time. Tube life is extended by at least 30%. I know this because before acquiring the P10, my amp was not happy.

    1. Bill, I am also a fan pf c-j amps. I retired by c-j Premier 12’s back in 2019, however, before that using a PS Audio P10 had the same effect on them when it came to setting the bias voltage. I still us a c-j preamp and phono preamp. Both are plugged into a PS Audio P15.

  7. Every setup will have its own weaknesses, so a power regulator may be the best answer for some rigs. Personally, I have never used one – filtering is the method that works for me – one solution that also worked was a DIY, own design chip amp unit, where the design was all about adding a full regulation power supply to feed the chip voltage rails.

    It’s nasty types of noise on the mains that are a biggy – IME, very hard to completely eradicate; and very damaging – gives you that “digital” unpleasantness that everyone loves to hate, 🙂 .

    Ultra clean mains, without worrying about voltage, I find a good solution – one way or the other, for me it delivers prime SQ …

  8. Great (and timely for me) post today Paul, thank you. I am considering the BHK 300/BHK signature preamp combination, and possibly the P3 or P12 because I live in an older house and based on various experiences over the years (occasional dimming lights, etc.) I assume my AC power may not be all that great. Before I make the P3/P12 investment I would like to have a sense of what a power regenerator will do for the the sound quality I would experience with the BHK 300. I recognize I can try the P3/P12 for 30 days and just see for myself, but before I do that (and despite my lack of technical background) I would like to understand at a high level how these products do what they do.

    As you suggested in today’s post, I won’t focus on distortion, just on AC power. I understand the concept of regulating the AC power going into the BHK 300 (thanks to your post) but I don’t yet understand how the regulated power translates into better sound quality. As the BHK 300 (or any other PS Audio amplifier, I suppose) makes use of the well-regulated power that the P3 or P12 provides, what specific aspects of the amplifier performance change to result in an improvement in sound? Also, what kind of before/after testing helped you and your team to understand what causes this positive impact?

    1. There’s a lot to unpack in all this and it’s a complicated subject. Regulated power in the way we do it (instantaneous regulation) improves current handling for lower power factor power supplies like those in the BHK amps. That basically means less power supply ripple and more energy reserves when needed.

      That all has a very positive sonic impact on sound quality.

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