pinpoint_oxford
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I only use an audiophile-grade cable for my kettle. Makes the tea taste so much better.
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PS Audio P12 Review Part 2: Power Testing
- Thread starter amirm
- Start date
Have you blind taste tested your tea and demonstrated that you can tell the difference 10 out of 12 times?
If not I call foul.
Good advice from the Anthem AVM-20 User's Guide:
Hello amirm, my first post here. Thank you so much for all of the helpful reviews. I was considering getting a P12 and this has convinced me not to do so.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
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.
Edit: my BK Precision Lab AC Generator showed 0.3 ohm impedance on the same test.
EDIT: After much waiting and back and forth, we got some clues from PS Audio that perhaps Zone D High Current outlets do not perform the same as the others. This, despite the fact that the manual says they do. And the specification says nothing about Zone D outlets having higher impedance. Company now says that Zone D is just pass through with some filtering. This is not correct as I tested it and it does regulate the voltage. And its output is just as clean/dirty as Zone A as I showed in my original review:
As you see, performance is nearly identical between the two zones. Regardless, I decided to re-run the above tests using Zone A, while being worried about damage to the unit since by definition, they are not "high current" outlets. First, new impedance measurement of Zone A:
Now this is a lot more reasonable than the 3 ohm impedance we measured in Zone D (HC outlets).
So I then tested the performance of Outlaw 2220 using Zone A:
There is no more power loss. But then again, there is no increase either. Nor has distortion or noise changed one bit. Let's see if peak power is better using Zone A:
First with Raw AC again:
And now with Zone A of P12:
There is a bit less power with P12 but we can give them the benefit of doubt that this could be within measurement error. We can conclude strongly that P12 does NOT increase dynamic power and hence dynamic range as the company and customers claim.
I hope the company updates its manual and website to reflect the poorer performance of Zone D vs the other. And also correct their public misstatements that Zone D is just a filtered port. It is not but for some strange reason, it has high impedance. The manual for some older PS Audio powerplants explain that there is an inrush limiter for high current port. That would explain the higher impedance. And why it would be bad as far as peak power for an amplifier.
Edit: here are the results with a Topping PA5 power amplifier.
Topping PA5 uses a regulated and hence switching power supply so I didn't expect its power to differ with or without PS Audio P12:
View attachment 190884
And that is what we get. Note also that there is zero difference in noise and distortion. The two measurements land on top of each other.
Testing for burst power we get:
View attachment 190885
There is tiny difference between the two which is almost within measurement error.
At the start of the test, P12's meter says incoming voltage = 122.7 volt and outgoing voltage = 119.7 volts.
Switching power supplies have built-in regulation to create a constant voltage and with it obviating for any upstream regulator like P12 PowerPlant.
Conclusions (updated)
When using the P12 as one would think to do: using Zone D "high current" outlets, impedance is actually worse than mains AC and hence it reduces power output in our test amplifier. When testing using low current Zone A, this doesn't happen and we get the same power, distortion and noise.
Bottom line is that at worst, PS Audio P12 objectively degrades the performance of some audio products if you use the Zone D outlet. If you use the other zones, it simply doesn't do anything useful than waste some power, take up space, and cost you a lot of money. Distortion, noise, dynamic and average power of all tested products remains the same as not using P12. This is what the data shows and after two weeks of waiting, nothing has been presented from PS Audio or anyone else for that matter, to indicate otherwise.
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As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
But I am curious what you would recommend in my situation. My mains power is regularly too high. It fluctuates from 122 to 124 volts. Usually closer to 124. I have bespoke 300b tube amps and the creator of them explained to me that part of the reason I get audible transformer hum from the amps is the overly high voltage from the mains. He recommended that I use a Variac to reduce the voltage to 118V. I am not so sure about this.
Could your test device (which seems to produce very clean Ac output) be used as a power conditioner for an audio system? What else might you recommend?
Thanks!
If he recommended a variac, give it a try as they are cheap. Just make sure it has the correct rating (current wise) for your amps.
LINK to "variac with meters" search - lots of choices out there.
I had one of these about 20 years ago - but it was only 9 amps.
Unless it is a vintage amp then 124 volts should not be an issue. For amps from the 1960's or earlier that were designed for 117 volts then 124 volts can be pushing it especially considering these amps are antiques and filter caps were pushed hard. I use a "bucking transformer", which you can build very inexpensively, (google how to) to drop line voltage from 124 volts to 117 volts for my antique amps and while not sounding better they did run cooler and were very reliable.
MakeMineVinyl
Major Contributor
Your power voltages are NOT too high! The range where you would have to begin to be concerned is if it dips down below 110 volts or above 130 volts. You best solution given your voltage levels is to simply do nothing.
I mentioned about 3,000 posts ago on this subject that I bought a regenerator (a PS Audio P3 from the previous series) specifically for a 22w 300B-xls amplifier. It was from Art Audio (Tom), a version of this one that took 300B-xls or 520B tubes.
Art Audio Harmony Silver Reference SET 300B 10w Integrated Amplifier
This is the Harmony Silver Reference SET 300B Integrated Amp. A similar design to our ultra musical Diavolo power amps but with multiple upgrades. There are no PCBs in the signal path, it is point to point wired using pure silver wire and we use pure silver coupling capacitors. The Harmony...
artaudio.us
Before a stream of posts starts about $30,000 for tube amplifier, all I will say is that I bought it used, had it for 3 years and sold it for about $700 less than it cost me and I took a small loss only because the buyer was a nice guy and a bit short on cash.
Art Audio have been making these purist designs for over 40 years. For about 15 years they had a workshop supplying a substantial USA market, until their distributor disappeared with a lot of their money and stock, and clones of their phono amp started to appear. Tom found they benefitted from regenerated mains, so for a while was a PS Audio dealer, which ended probably because he was only really interested in 2 or 3 of their products. Tom was not an audio dealer, he was mainly making bespoke tube amplification to order. He still does. His designs don't have mains filters and that kind of modern stuff, he once told me they are basically 1930s technology.
I sold it because I came across a pair of Art Audio KT88 monoblocks in the USA. They had been blown up somehow and were unserviceable in the USA. I paid something like $1,000, shipped them to the UK and Tom fixed them for about $1,500, half of which was having to change the mains transformers from 120v to 240v. (Listed on that site for $16,500!). I sold those (for a profit) when I moved to less sensitive speakers about 6 years ago and bought a Class D amp, which I still have.
The Class D amplifier is completely indifferent to mains power, so I sold the regenerator.
I'm not fighting PS Audio's corner and I don't own any of their products, but that was my personal experience with a 300B amplifier.
p.s. A regenerator would obviously protect the amplifier, and they can be expensive to fix, whereas a basic line conditioner and surge protector may starve them of power, and mine were very power-hungry.
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solderdude
Grand Contributor
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MakeMineVinyl
Major Contributor
I got an industrial strength Topaz Line 2 AC voltage regulator for free a long time ago, and it keeps the voltage within somewhat tight limits. Its a switched primary type regulator. I haven't used it for years since my AC mains is already pretty good and the Topaz does waste some degree of energy through losses in its transformer. The thing weighs a ton and it emits enough acoustic buzz that it has to be kept in a closet.
SuicideSquid
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This is well outside my area of expertise; however, it seems to me that if this amplifier cannot handle a swing in AC voltage of 6 volts, this is a problem with your amplifier and not with your mains voltage.
Well using a variac does make for one big azz volume control.
And if a variac was good enough for Eddie Van Halen's tube amp ... well, there you have it.
JSmith
Master Contributor
Well if you got a P12 and used the HC outlet, you will get less voltage as per results.
There are plenty of proper AC/DC/AC regenerators that cost 1/5 or less than the price of this waste of money.
122/124V is very close to 120V and certainly within the tolerance range of +10% -6% (actually + or - 10% in the US).
Transformer buzz is not always caused by voltage issues either... there could be a a DC bias for example and torroidal transformers can become saturated in that case. Have you tried a DC blocker? May be a simple solution.
It could even be things like interconnects that have a broken or cracked ground path or faulty input terminals on the amp, or on your source or pre causing a hum.
JSmith
I think @Lonetoe should try a regenerator. He can always return it if is of no benefit.
For this type of amplifier, particularly a demanding one like a 300B, and the subsequent KT88 units, I found a clear benefit.
I have used continuous power supplies for about 15 years to protect computers and servers. I have two of them in my office now, an APC and a Cyberpower (the battery on the latter seems to give up very quickly).
I used to have a music server/streamer that used Naim SQL software that corrupted after power loss, so I put in an APC in the stereo cabinet to protect it. I did on one occasion connect the 300B amp to it, out of curiosity. I recall the result was very disappointing, it seemed to kill the quality of the sound.
A really good 300B or similar tube amp with the right speakers (in particular a pair of Lockwood Tannoys which I think had 15" HPDs) is a glorious thing. It's unashamedly old school and you won't find anyone discussing SINAD or anything like that. Amir would tear them apart (see the measurements of Tannoy Churchills on Sterephile), but they have a speed and detail that is uncanny and they just draw you in to the music.
It's not even necessarily a matter of voltage stability. My voltage was very stable, within 1 volt. I think it is more to do with the power demands of this type of equipment.
The quality of the components, primarily the transformers, is critical. As @Lonetoe says he had his amplifier built bespoke, I would expect the quality to be very high.
DonR
Major Contributor
If it can't deal with a +-5% voltage swing in the mains, then it's poorly designed, regardless of the quality of the components. "Speed and detail" have absolutely nothing to do with the mains (outside of an extreme situation) and everything to do with the amps designed frequency response and slew rate. The "power demands" are, again, a function of the power supply design and not the mains supply.
OP
I agree with @amirm in that I've had a regenerator with modern components with well designed power supplies plugged in and it made no difference. With one of these 300B SET amplifiers it made a significant difference. I don't know if you or others have used one, and a good one, but unless you have you won't really know.
In my experience, if you deal with people in an honest, respectful and polite manner they react accordingly and you get results. I had another result just last week on a faulty home automation product. If I was @Lonetoe I would call PS Audio, say he was about to purchase an item, has read your reviews, is now uncertain and would they cover the return shipping if he was not satisfied?
I have never paid carriage on loan or S/R items. I had one a month ago, the dealer just sent a label and it was collected the next day.
Hey folks. Thanks for all the replies. Here is some more information. The amps are push pull 300B’s made by Deja Vu and they sound wonderful. I have tried many different amps over the years and these are my favorites by a large margin. There is nothing wrong with the amps and they have handled the 124+ voltage from the mains (through an Adept Response power conditioner) for several years now without any problem. There is just an audible transformer hum when you are close to the system. Listening at all but very quiet levels, the hum can’t be heard. It’s just a little annoying knowing it’s there.
There is no ground loop issue and there are no cable faults. I have no problem manually biasing the amps to their correct specs.
It would honestly be great if a good USA made variac would solve the problem — I just have my doubts. It’s a lot less expensive than the PS Audio product, and I already have an excellent power conditioner. But I am not all that excited about a $1000 experiment for something that isn’t all that critical to solve.
There is no ground loop issue and there are no cable faults. I have no problem manually biasing the amps to their correct specs.
It would honestly be great if a good USA made variac would solve the problem — I just have my doubts. It’s a lot less expensive than the PS Audio product, and I already have an excellent power conditioner. But I am not all that excited about a $1000 experiment for something that isn’t all that critical to solve.
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