PS Audio P12 Review Part 2: Power Testing

[LEFASR160]

Exactly, that's why Amir said what he did. It's clearly not a true number.

@restorer-john then we're in total agreement. And you also said that the drop in power might be explained by a over voltage in the Mains with the P12 down regulating it, in which case the entire test is meaningless.

 

[Barry_Sound]

This. Loose thought from a non-engineer: If a bog standard PSU for 50-100$ will suffice to feed a big gaming PC, with its much more stringent power quality requirements than any home Hi-Fi device, there's probably no much real need for such a "regenerator". The only exception in my life so far was with my Neumann KH 310A, which were "upset" (intermittently protection LED on for a second and clicking) by outside interference, probably by some agricultural machinery nearby.
A small, affordable filter eradicated the problem: https://www.thomann.de/de/furman_ac210_power_conditioner.htm

How is this even possible? I thought those conditioners are - according to what I learned here - pure snake oil?

 

[voodooless]

It's a high voltage amplifier capable of swings over 200V. It would need 170V to do 120V RMS with no losses.

The easiest way to do that would be with a bridge configuration to keep voltages low and costs reasonable. The picture I found suggests that too.

Bear in mind, this is guesswork, but I'd wager a bridged class B pair with tons of feedback to lower the output impedance and a narrow bandwidth.

View attachment 190666

Still, none of this proves it’s rail voltages can get it higher than the input. It’s all dependent on the winding ratio of the transformer.

 

[Barry_Sound]

While with low current devices we could hardly find a harm caused by the PS Audio P12 (other than to your bank account), with power amps we are seeing a distinct degradation of power. In this regard, I think any marketing material without proper objective back up to the contrary is irresponsible here. Please heed the advice from me and many amp designers that you don't want to use these regenerators for power amplifiers.

No expert but did PS Audio state anywhere the PS12 would give anyone "more power"? I dont think so. They are claiming "sine-wave-perfect, regulated high current AC power." In the end, by manufacturers claims, this is an audio product. Wouldnt it make sense to measure system output (aka "sound") with and without the PS12?

 

[amirm]

No expert but did PS Audio state anywhere the PS12 would give anyone "more power"?

They sure as heck imply it: "The results of feeding your equipment with low output impedance are dramatic: unrestrained dynamics even under the loudest passages, an open, wide soundstage that does not collapse with volume and a naturalness to the music that is remarkable."

Post after post made the claim that dynamic power is increased in a power amp. I am assuming they are getting this impression from PS Audio.

 

[amirm]

You don't have a multimeter?

I thought I post an answer to this but now I don't see it. A multimeter is way too slow and out of sync with what AP is doing to compute power with 1% THD. AP will iterate quickly to change the output power until it hits 1% THD. During that process, the amp is producing varying outputs from low to max. A simple meter has no prayer of capturing the voltage right at the moment AP is computing max power.

 

[restorer-john]

Still, none of this proves it’s rail voltages can get it higher than the input. It’s all dependent on the winding ratio of the transformer.

With respect, you are not understanding the concept.

The transformer determines the secondary voltages the amplifier has to swing within, as with any amplifier. The transformer is likely to be a 120-120V (likely higher) CT transformer, supplying the two amplifiers operating in BTL. The range the device can regulate within is specified at 95-145V for a regulated 120V out. So, at 95V in, the transformer secondary voltage and consequent amplifer supply rails are well above what it needs to regulate a 120V RMS output.

So we know at 95V in, the output is 120V RMS regulated out. That's +/-170V required. That can be obtained with one high power amplifier capable of swinging well over 340V P-P or two amplifiers capable of +/-85V swings running in bridge. One is difficult the other easy. (Again, these no-loss figures are just illustrative, the losses are significant and voltages/drops are high)

 

[JustJones]

Wouldnt it make sense to measure system output (aka "sound") with and without the PS12?

No, how is the sound going to change ? we're talking about 350 to 500 watts if the speaker doesn't blow then your ears will ring for a few days. It's like saying unplug the amp from the bottom receptacle and plug into the top one to see if the sound changes from your speakers??

 

[amirm]

Wouldnt it make sense to measure system output (aka "sound") with and without the PS12?

That is what I measured both in this thread and the original. I did realize that I had one more amplifier measurement I forgot to include in this thread:

As you see, the two curves land on top of each other except that the amp clips sooner with P12. This again is the output of the amp. As were the other previous power measurements.

 

[Ingenieur]

Nice evaluation.
The 0.23 Ohm is accurate within a few percent and 0.02 Ohm
That means you could deliver >500 A to that outlet. In 4 mSec.
Power supply is seldom the issue.

 

[don'ttrustauthority]

I have a problem with ground loops, but my Amazon el cheapo dealio seems to fix those. I suppose I could get it even quieter, but the way to do that is by rewiring the house, not fixing a problem with expensive gear of questionabl no value.

 

[AudioSceptic]

I recently reviewed the PS Audio PowerPlant P12 AC power regenerator. There, I measured its performance with either no load or typical source device. Questions were raised as to its performance with higher power loads. Here is that test.

View attachment 190503

So I unpacked and lugged the 50 pound P12 back to my lab , and paired it with an Outlaw 2220 monoblock. This is a linear amplifier and doesn't have a regulator power supply meaning it can produce more power if allowed.

To give the P12 full benefit of doubt, I used a Pangea AC 14SE MKII Signature Power Cable (2 meter) to feed it AC. It costs US $120.

PS Audio claims or implies that you get more dynamics and power due to P12 having lower impedance. We will test this.

PS Audio P12 Measurements
Let's test the power capability first and foremost by measuring maximum and peak power of the Outlaw 2220 power amplifier using my standard "Raw AC" wall power:
View attachment 190504
These are my standard measurements but in case you are not familiar with them, on the left is more or less continuous power if we allow the amplifier to reach 1% THD+N. I say more or less as the test lasts about a second or two in each try.

On the right the duration of the signal is much lower. As explained, we have a sine wave that stays at low level (and hence power) for 480 cycles but then peaks to full value for just 20 cycles. This standard was created for car audio manufacturers that want to throw out big numbers for watts. As we see, the outlaw does produce a lot more power, reaching more than half a killowatt. This is far more than the base measurement because the power supply capacitors can maintain that duty cycle well enough to generate that much power.

Now let's route the 2220 amp through PS audio:
View attachment 190505

As you see, we lost 7.5% power in both continuous and burst power. As should be the case as the PS Audio P12 is introducing losses in the AC line.

Edit: I forgot to include the THD+N vs power:

View attachment 190673

As you see, noise+distortion is not changed with P12 but power is decreased by nearly 30 watts.

As another test, I have an Ideal AC line tester, the 61-164. This is a $400 instrument for quick and useful powerline measurements. One of its unique features is ability to measure the impedance of each of the three lines in your AC mains. Let's focus on the Hot wire and see how my standard power strip that I use for powering everything ("Raw AC") performs:
View attachment 190506

Impedance is just 0.26 ohm. When we remodeled our home I made sure every circuit is powered using 12 gauge as opposed to 14. And my power strip is a beefy one as well. I am also not hugely far from our breaker panel.

Now let's power the PS Audio P12 using the Pangea power cord and measure the impedance of its high current outlets I used for previous testing:
View attachment 190507

As you see, impedance has jumped to 3 ohm or more than 10 times higher! I should note that I don't know how accurate this measurement is but given the wide differential, we can likely rely on the fact that PS Audio P12 *system* does have higher impedance. I wrote "system" there because P12 introduces yet another AC cord and outlet so naturally those contribute to degrading its impedance. In other words, we are measuring the whole thing, not just some internal impedance.

Conclusions
It is clear from the above tests that using the P12 degrades available power to an amplifier, not increase it. Both continues and dynamic power are limited, as they should. You are inserting another cable and box (power regenerator) which has its own losses. Burst capability in power amps is provided by its internal power supply capacitors that have a very low impedance path to the amp being inside it. Trying to do that with AC is like pulling the end of a wet noodle and expecting the other side to move with it.

The data here is the reason a number of power amp manufacturers recommend to power their units directly from the wall and not through a AC regenerator. You want the least impedance path to the AC outlet and that is a simple power cord.

While with low current devices we could hardly find a harm caused by the PS Audio P12 (other than to your bank account), with power amps we are seeing a distinct degradation of power. In this regard, I think any marketing material without proper objective back up to the contrary is irresponsible here. Please heed the advice from me and many amp designers that you don't want to use these regenerators for power amplifiers.

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As always, questions, comments, recommendations, etc. are welcome.

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Wow, just f***ing wow!

 

[AudioSceptic]

It's a shame to see that a well-respected company like PS Audio is moving more and more into the snake oil business.

Well respected? Please tell us.

 

[LEFASR160]

That is what I measured both in this thread and the original. I did realize that I had one more amplifier measurement I forgot to include in this thread:

As you see, the two curves land on top of each other except that the amp clips sooner with P12. This again is the output of the amp. As were the other previous power measurements.

@amirm good analysis !!! You've got a few typos though...on this and several other graphs you have "P15" when you meant "P12". Everyone here knows what you meant but others may get confused.

 

[AudioSceptic]

Ah yes... the decimal point.

You of all people missed that? ;-)

 

[SoundsGood2Me]

Thanks again Amir!

I wish there was a LOVE button.

Oh wait, there is

PS, pic not related, just my turntable setup - Fully Balanced from the cartridge on, currently running a Grado Platinum cartridge.
You should waste $$$ on SACDs instead!

 

[kongwee]

Any amplifying unit shouldn't plug in to any filter or conditioning or regeneration. It is common practice for well informed audiophile. Even amp manufacturer agree too.

 

[Rottmannash]

@amirm isn't the max output of the Outlaw 2220 beyond the P12's output specs? Assuming you were running both channels, you'd expect to come up against a brick wall at around 350Wpc continuous. Or am I missing something here?

I'm sure you're keen to put this one to bed, but it would've been interesting to test the P12 with, say, a 100W amp, so that the P12 stays within its output specs at all times.

It's a "monobloc" amp. One channel.

 

[Jim Shaw]

I'm proposing this pink buddy as a symbol for snake oil products.

View attachment 190508

Yes... or this. But this may be copyrighted, though none is visible.

 

[soundwave76]

I'm proposing this pink buddy as a symbol for snake oil products.

View attachment 190508

YES! Somebody here who owns a 3D printer needs to make one