Where PowerPlants might not excel

So I asked a very experienced audiophile, who is a low-power purist tube gear aficionado (naturally, meaning also very efficient speakers), what he thinks about the possible limitations of PowerPlants. He and his friends have noticed in the past, and from anecdotes he’s heard of the current production PPs, that especially with flea-power purist SET amps plugged into them can be detrimental due to the high internal resistance of the capacitor banks (limit in fast transient current delivery), a problem which according to him can not be overcome with the amplifier circuitry at the core of PPs.
He suggested to only use a PP with source components and even there, the bigger the PP the better…

I believe him, but it’s quite the contrast. I have never really seen people with BIG current-hungry amps complaining about PowerPlant performance, given a sufficiently large one. One would easily think, wouldn’t the limitations of PP technology be more apparent there? But no, it’s the other way around apparently.
A purist flea-power SET amp with premium components and wiring with minimal signal path could really be more revealing of everything that’s going on, when coupled with speakers that are so efficient they might translate a whopping 10% of the power fed into music and only 90% dispersed as heat. Even though such amps aren’t current hungry - it’s the instantaneous current delivery speed that would count enough to be more notable than the output impedance benefit.

This is just how I understand it, might be wrong.
What do you people think? This certainly isn’t the only time either that someone with a purist system has felt that it’s better without a PP, given that the line AC is good.

Based on my experience with a 2.3 watt Decware amp and a First Watt SIT3, that is incorrect. Those amps and my P20 are super best friends; P20 improvements are easy to hear.

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What I’ve read is “it depends.” I’ve seen reviews that say if you’ve got seriously unimpeded AC and a big-watt amp, you should plug into the wall or use the PP’s filter-only setting, bypassing the regenerator. I’ve also read where some tube pre-amps have their own power supply technology that can be affected or nullified by power regenerators. I guess the best solution is to talk to manufacturers, read reviews, and take advantage of evaluation periods.

I must be falling behind on the newer PPs’ capabilities. I thought the choice between regeneration and “filtering” was a matter of degree or emphasis not a choice of one or both.

Care to clarify? (Or maybe someone else will chime in)


Care to clarify? Wow, you mean I actually might know something here that someone else doesn’t? Seriously my experience is of the PP 3. On the back there’s a switch for HC (high current) where all it does is clean up the incoming power. For the other outlets, they use fully-regenerated power. If your amp is below 700 watts (PP 3), the regenerated part is probably powerful enough to give the same amount of AC recovery, etc. But if the amp is bigger or you don’t trust the regen to do it as well, you can opt to get everything from your AC setup plus basic clean-up filtering. Bear in mind that if you haven’t taken steps to improve the AC- like 20A breaker, 10AWG wire, better outlets, cables, etc., you might be better off using the regen option anyway. Hope that helps.

Right, that’s a feature only on the early P3 as I recall, it was not on the P5, P10, P15 or P20.


I agree Ron, I’ve tried all my Decware components individually and collectively plugged directly into the wall outlets, and the clear improvements of my PPP, P10 and P15 are so evident they get unplugged from directly into the wall in short time.

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It’s still a feature of the current (bad pun) P3. https://www.psaudio.com/products/stellar-power-plant-3/

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Cool. It’s only a P3 thing though.

I am familiar with the HC switch option on the PP3. Now that you clarified you were referring to PP3 and the HC switch, I understand what you meant by “filter-only” and your comment makes more sense to me. Thanks.

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Okay, could be that who I asked was not really in a position to comment, because he hasn’t heard the new production PowerPlants.
But yes, something like a P20 as mentioned by @RonP surely has no issues. It’s behemothian after all.

Still I do kind of believe that high-power solid-states are generally more immune to mains quality than flea-power purist SETs. All logic tells me that a revealing low-power amp (with very efficient speakers) is more sensitive to all changes in AC. A brute amp can cheat here so to say.
The same principle how a phono signal, being minuscule in level, is most sensitive to everything that could affect it.

Would the p20 work with a big krell amp that has an 8kva transformer and a pair of apogee scintilla speakers? It would seem like the amps power supply would be bigger than the p20’s power supply.

This does not make sense to me.

One of the biggest advantages of the power plants is their low output impedance. This is much lower than the impedance of the power coming out of the wall.

A power plant can thus deliver power faster with less resistance than the wall - including to a SET amp.


Indeed. 10 gauge wire has a resistance of about 1mOhm per foot. Most houses are using 12 gauge which is about 1.6mOhm per foot. There are caps with ESR’s in the low mOhm (e.g. ceramics, film, aluminum polymer, tantalum polymer caps and sub mOhm for some film caps) and you can put as many of those in parallel as you want. A power plant can’t maintain a higher output current at the same voltage as the wall for long periods of time, but it can provide higher output current for short high demand pulses which is what many power supplies need.


Yes, it would. The reason it seems wrong is the size mismatch. The reason it works is because you’ll never get close to using all that is possible in the Krell (and the Scintilla’s power hungry nature). Put another way, the 1,000 or so watts the P20 can effortlessly produce is more than you’ll need to play music.

What would this imply for pure class-A?

Nothing, unless the the amp continuously demands greater than a continuous 2000VA, which is incredibly unlikely.

Then why did I buy a power plant from a manufacturer of a pure class A SET amplifier, who was so enamoured with regenerators he became a PSA dealer?

Class A amps only draw constant current from the wall if they are using switch mode power supplies.


I’ll have to try and get this person who was talking about the mentioned limitations to try a modern big power plant…

Yes, I did initially too think it was strange that a sufficiently powerful power plant would limit the dynamics of a low-power SET amp. Aside from the current vs wall, there are so many advantages… But I also can’t close out the possibility that that’s really what he, or his friends, or someone, heard.