P12 Voltage Dips

Hi Everyone. Having an issue with voltage dips on my P12. It didn’t used to dip at all. It was rock steady. I believe the difference is that my power amplifier is now plugged in through the P12. But I’m not certain when I started plugging in into the P12 so I am not positive that’s the reason. Even with my amplifier, the system never draws more than about 500w. I mean even at full volume it doesn’t draw that much. So it should be able to handle my amplifier, right? What could be causing my voltage dips then? I run a dedicated 20A circuit (two actually). The P12 is on my 2nd circuit with all source components and my power amp. The other 20A circuit contains my powerful theater amplifier and a few odds and ends for my turntable (lamp, speed controller, etc). Here are the screen shots. One for this week and the other for last month. I did not fire up my system last night so you will see perfectly flat voltage.

This is from February:

And this one is from today:

I should clarity that the dips occur only when the system is powered up. And the last few nights where you see the deeper voltage drops, I was listening at live levels. It would seem obvious to me that the system is over-powering the P12 but it shouldn’t IMO. I am well under half the rated draw. Admittedly, I have a lot to learn in regards to current draw and relative power, etc. Hence why I created my post. Thank you everyone.

Something to keep in mind, this is dipping on average less than a volt. That’s hardly anything. Also, I’m going to almost guarantee it’s the fact that you recently plugged in your amp. As the demand from the P12 goes up, its job to keep the voltage stable at 120 becomes much harder. This is why we’re always recommending more headroom with the P15 or P20. Though 500W doesn’t come very close to what the P12 can handle, it’s still a fair amount for it and it’ll be working decently hard to supply that current. The ratio of current draw vs capable load will be significantly bigger with something like a P15 or P20 and I’d bet you wouldn’t have these dips with them.

1 Like

Thanks James. I’m going to listen this weekend with the amp plugged back in to the wall.

I was told the P12 could easily handle my system before buying it, so that’s why the concern. The 500W figure was also a gross over estimate. During the last few nights when I listened fairly loud, the draw on the P12 was never over 346W. But it is what it is I guess. I’ll have to start thinking about upgrading if I don’t like the way the amp sounds while plugged into the wall.

The P12 can’ handle this no problem. even if you’re sipping up into the 600-700W territory. I just wanted to mention as you go up in current draw, the P12s ability to output a flat 120 will be harder. Not to mention possible dips in incoming voltage. If you like the way the amp sounds in the P12, I really would not stress about a dip of less than 1 volt occasionally.

1 Like

Just what I needed to hear. Thank you James!

Have you checked to make sure the Mode is set to High Regulation? (This is the default and it probably is, but it is worth checking.


Great point Elk!

1 Like

Elk, you could have a great point. I was just letting James know via PMs that I should go into the unit and check all of the settings as I might have accidently changed something. It’s also worth mentioning that my Roku Ultra remote is on a similar frequency as the PS Audio remote (I have turned off the P12 with the Roku remote several times). So it likely could have changed something!
On a side note, I looked over the graphs on my P12 and it was very steady a few weeks ago. The voltage didn’t swing at all and yet I know my power amplifier was plugged in back then. Thanks for the tip!

1 Like

For a start, one and two volts are not considered huge. My incoming voltage drops by 6 to 7 and spikes by up to 8 volts. However, in my case the this is not associated with a drop or a spike in the outgoing voltage. In the case we see above a drop in the incoming voltage and the outgoing voltage almost concurrently happening over 3 or more hours each day. This begs the question @Elk asked regarding regulation settings.

I checked the settings and it was definitely in High Regulation mode. Last night I moved my power amp to the wall outlet and it was even worse. The P12 mirrored the incoming voltage when it dropped. It wasn’t regulating at all for the 3+ hours I listened… But I think I figured it out. Apparently my power amplifier is quite the little power hog. Even though the P12 doesn’t register it as drawing much wattage. So the P12 might be able to handle it (an Ayre VX-5 Twenty) but I don’t like that it dips - even 1 volt. I’m sure the dipping is only part of the story in loss of fidelity. Luckily, I have two 20A circuits so I moved the Ayre to the other circuit and everything else including the P12 to the opposite circuit. Output voltage by the P12 doesn’t waver much at all (.1V!) even though incoming voltage drops 1+ Volt. What I was mostly concerned about was why the change from 3+ weeks ago to now. I’ve had the Ayre connected to the P12 for at least a month and it used to be just fine. It’s just strange… Now it can’t handle the Ayre on the same circuit without some sagging.
But all sounds great as it is so I won’t worry about upgrading to a P15 or P20 just yet. Thanks for your help and suggestions guys.


Good experimentation and information.

It bothers me we do not have an explanation as to why the change in behavior however. I’m concerned there may be something going on with your P12.

What is the incoming and outgoing THD?

Glad it’s sorted with no loss to music quality. Great amplifier, by the way. Enjoy the music.

1 Like

@Elk you may be right. It was fine for the first few hours and then it started dropping again. The THD is 2.2 - 2.4% incoming and outgoing is locked in at .1%. It has never budged from .1%. So it’s like the P12 is set to lowest THD instead of High Regulation. I toggled it back and forth to make sure it wasn’t stuck but no change. Here is another screen shot. You can see Friday Night where it did nothing to regulate. And Saturday around 4pm is when I moved my Ayre amp to the other outlet. It seemed OK for a few hours then started being erratic. During this time there was 200-225W running through the P12. Seems to be getting worse with less wattage, not better.

Try high regulation and phase tune set to zero.

1 Like

@Serhan will try Phase Tune 0. It was at 3, which I assume is how it gets shipped since I’ve never changed it. Thanks for the tip.

Good luck. Would love to know the outcome. :blush:

Regulation capacity of PSA power plants is amazing.

@Serhan no change with phasing :frowning: I have a call into PSA and await a call back to see if we can’t trouble shoot this. Your chart is how my P12 started out for the first 3 weeks but now it looks like a seismograph when it’s running audio through it.

The reason I decided to call is because I ended up watching the display for a little while last night. It showed 119.9 - 120V out while I was watching it. - consistently but I didn’t have the patience to watch it for more than 30 seconds or so Powerplay charts show that the P12 dipped down to 119V several times around this same time. So it begs the question of how and when those charts get their data to form the plots. Is it a snapshot at even intervals or an average? And of course the bigger question is, which is correct? My unit’s front display or the Powerplay chart? I imagine PSA could monitor it on their end for a bit since we’re already communicating via ethernet. That’s my hope anyway.

I hope it is not affecting sound quality and I am sure the techies will get to the bottom of this and resolve it to your satisfaction. May be a reset can solve it.

1 Like