My (new to me) P10 clicks all by itself.


Hi guys. I bought my first bit of PS Audio kit a few days ago as a pre Christmas present. It is a previously used P10 in unmarked condition, UK spec, about 3 years old. I have upgraded it to firmware .41.

I have a DAC connected to Zone C and permanently on. The two HC zones D and E are used for my tube power amps and I use the soft start feature to power them up which is very useful. Zones A and B are unused and are off.

My question concerns noises that sound like relays coming from the P10 on a random basis. These noises happen both when the power amps are powered up and also when they are off, ie when just the DAC is connected and powered up. This is not the relay clicks from when I switch those zones on, they are clicks that just happen on a random basis.

The DAC draws about 20W at 240V. The power amps draw about 500w. However I don’t think this is relevant because it happens even when only the DAC is powered.

I have the P10 set for Low Distortion, 235V output, Multiwave, MW Strength 4, Phase Tune 0. The usual THD in is about 2% and out is about 0.1%. Voltage out is maintained at around 234.5V. Voltage in varies between 245V and 253V.

Are there any relays inside the P10 that could activate themselves on a random normal basis? In other words, is this normal behavior?

Thanks, Nick


I don’t recall P10 making random clicking noises as you describe. If you have a sick P10, typically unusual clicking noises, or high output THD are the give-away that something is wrong with the regenerator. By the sound of it all your performance parameters are normal, except for these random clicking noises. I’ve got a hunch that P10 has a bypass mode with relays that will bypass the regenerator if a fault is detected, but that aspect is better clarified by a PS Expert. Unfortunately the owners manual doesn’t provide much assistance for troubleshooting.


Thanks for answering on Christmas Day! As you say, it probably needs a PS Expert to give a view.


The PowerPlants have a rely to switch to the power coming out of the wall when the Power Plant is unable to address the problem(s) with the incoming power. It is a bypass relay which switches the unit from regeneration mode to letting the power from the wall through. Usually the problem is fluctuating voltage.

My guess is it is having difficulty with maintaining 235V output when the incoming voltage is 253V. It may be worth watching to see if it clicks when the voltage fluctuates.

The clicking may lessen if you adjust the outgoing voltage to a higher value.

I believe the unit is operating as it should. The problem would likely go away if you moved it to another location where the voltage is more stable.


Sounds like the heat sinks expanding and contracting.
I got that noise frequently when I had tube amps drawing over 600 Watts.
Not so much now that I am using BHK mono amps drawing about 300 Watts.


An excellent suggestion, but the OP reports it happens even when the P10 is supplying only 20 watts.


It could easily be the expanding metal of the heat sinks. This can trick folks. But, if it is relays inside, could be something in the AC line triggering the bypass relay. This happens regardless of output delivery if there’s something wonky on the line.


I considered that.
Could be the timing.
The heat sinks could be cooling down after the tubes amps are shut off and the system is only drawing 20 Watts.

If it still happens after the amps have been off for a long time, then it is obviously something else.


I did not consider the heat sinks cooling down, good thinking.

Unrelated, but I enjoy the tinkling of power tubes cooling.


Thanks for the input.

It is not the cooling of the tubes or of the P10 heatsinks. It happens even when the tube amps have been off for hours.

I will try upping the output voltage to say 240 and see if that changes anything.

One of the attractions of the P10 to me is that it can tame the overvoltage.

Can I ask if anyone knows if it affects the P10’s ability to cope with high incoming voltage if I change to voltage control rather than low distortion?


With an input thd% of 2% or less, I set my power plants to focus on high regulation instead of low distortion.


Yes - I agree on the 240V setting. In fact, I’d have done that even with no perceived errors, just because the P10 will have a lesser load, having to cut or boost less volts. The P10 is indeed capable of handling large voltage swings (unlike it’s predecessor, the PPP). Still, 240V won’t harm your equipment and the load on the P10 will be lower.

Also ensure the unit is properly calibrated. [Ensure you do this in Sine mode, unless using a true RMS multimeter].


Thanks. I have set the output to 240V and will see what happens. I have also set the output Mode for High Regulation. I have an accurate true RMS mulitimeter and the P10 output voltage is about 0.5V lower than the output voltage setting. In other words near enough to make no difference. Just as a check of my multimeter the sine wave and multiwave outputs were identical voltage.

I am slightly confused about the logic that setting the output voltage to be closer to input voltage would mean that the P10 somehow has to work less hard. I thought that the P10 was essentially an amplifier outputting a generated and amplified sine or modified wave and as such the difference between say 253V input and 230V output should not be an issue because the P10 is not modifying the input voltage and is instead creating a new AC wave and voltage from the inbuilt amplifier. I can see that the other way around a low input voltage and higher output voltage might cause issues because one might not be giving the regenerating amplifier enough power for the expected output. Am I missing something here?

I can understand Paul McGowan’s point that something in the AC supply that might trigger a bypass relay. @adminpaul I would be interested to know in which circumstances the P10 is designed to activate the bypass relays (edit - and how soon after the ‘event’ they reset)

In the meantime thanks for the suggestions and I will see if it makes any difference.


I’m not technical, and do not understand the logic myself. I could be wrong, but it has always been my understanding that (almost) regardless of the input voltage, the P10 has to “work” equally hard cutting or boosting voltage. Perhaps Paul or Bob could chime in … it is very possible my understanding is wrong.


My understanding is that the P10 does not generate a new sine wave.
It supposedly “repairs” the incoming power.
If true, that could explain why matching input and output voltages is desirable.


From the PS Audio web site,

“The PerfectWave P10 Power Plant takes your incoming AC power and converts it to DC, similar to what comes out of a battery, and then with patented PS Audio technology regenerates and produces new sine-wave-perfect, regulated high current AC power. In the process of regeneration any problems on your power line such as low voltage, distorted waveforms, sagging power and noise are eliminated.”

So the incoming AC sine wave ceases to exist when the incoming power is converted to DC. The output AC is an all new wave form and the voltage and current capabilities are provided by an amplifier. Apart from the amplifier requiring to have sufficient current available from the DC I do not see how the output voltage is related any more to the input voltage.

Anyway, no point guessing when those who know are around . . . . .


With the original Power Plants (as I recall) new power was “built from scratch”, which made them terribly inefficient - 50% I think.

PPP and later units apparently used different technology … “riding on the incoming sine wave” seems to come to mind, though I cannot remember what that means. sorry_gif


The P10 does indeed generate a new sine wave and that’s what’s powering your equipment. It has a limited range it can work from, which is normally well within the typical highs and lows of power. There’s no more difficulty in bucking (reducing) than boosting.

I think the advice to focus on regulation as opposed to distortion is perhaps good.


Paul, many thanks for that information.

Paul McGowan said

It could easily be the expanding metal of the heat sinks. This can trick folks. But, if it is relays inside, could be something in the AC line triggering the bypass relay. This happens regardless of output delivery if there’s something wonky on the line.

Is it possible that you or one of your techies can answer my earlier query about what events on the incoming mains will trigger the bypass relays which I assume bypass the regeneration process and then how and when are the relays set to return to supplying regenerated power?


Have you noticed the distortion reading just before and after a relay event?
If the output distortion is the same as the input distortion, then you are most likely in bypass mode.
If the output distortion is constantly low, it is not in bypass mode.