Break in time P10


What can I expect from the P10 breaking in?

This week I’m puzzling how to get the magic back in my system. The latest changes in my system are a P10 and a two AC12 powercords. The P10 is about 3 weeks old and the powercords about a month and a half.

Actualy the sound is really good but I need that final tiny adjustment.

The problem I have is that my system is growing and growing the sound is almost getting to big for the room. So what I need is a bit more crispy in the hights. Probably I need some smaller speakers or something.

Is the P10 going tho be sound a bit crisper in time? Or should I start to find a solution in adding another powercord or something?

Who can advice me? By the way the sound is very enjoyable, but I feel there’s one more step to go! As always!

Thanks in advance,



Often when I ask for help! I find something which need some time. This time I removed some tweaks in the form of cable wraps on the low voltage powercable to my preamp. And I replaced an Oyaide GPX-Re for a less expensive Kemp powercord + to my poweramp. The sound became more crispy and it is very enjoyable!


I wouldn’t let this ponder on your mind…the P10 is what it is, and no doubt its use over time does result in very subtle changes to the internal components that might bring about even more subtle changes to the things that are connected to it. One thing is for certain, the P10 is the rock solid foundation that provides a steady constant for which other changes in your system can be assessed, any time of the day or night… Don’t worry about it, let it do its thing, assume it is the steady constant and enjoy experimenting with everything connected to it.


@brodricj Thanks for your conclusion! I will start experimenting to find the most perfect setup.

At the moment I feed the P10 and the PWD with the best powercords the preamp end the CD player with the second best and the poweramp with the thirt best powercord. This seems the solution.


What very interesting is, is that the P10 Phase and Neutral connection seems very important. On the 9 sockets I have the phase on the right and neutral on the left seen from behind the P10.

Yesterday I accidentaly flipped the feeding powercord and changed the Phase and Neutral connection. The problem with the humming poweramp transformer was back just like I had with the P5.

What I don’t understand with switching the Phase and Neutral connection is that it also changes the output Phase and Neutral connection. Normally with equipment like frequency transformers (used for driving an electro motor) also makes a DC voltage before generating an AC voltage again and it doesn’t matter how the feeding Phase and Neutral is connected, because of the DC voltage in between. But for the P10 it matters hmmm interesting!


Here we call them active and neutral. When you flip them around we call it reverse polarity. We have seen issues with some P10 and reverse polarity, so my suggestion is to keep all connections straight through both on input and output. If in any doubt use a power point tester, they’re cheap, only about $20, and they also test for other incorrect wiring and fault conditions.


Well we dutch would say you call it wrong than, because they are both active parts ground is not :smiley:

But thanks I will use them in the future!

For almost all my equipment I know how to connect the active and the neutral. I meassure all the time. Besides that for classe equipment they have a tester build in.

I mentioned the Polarity for the P10 to help the community In the first place. And I would say the polarity on the output sockets need to be active right and neutral left. This way the P10 sound it’s best. I also had trouble with the poweramp transformer humming when it is reversed in the past with a P5 and this week also with the P10.



I have the same problem with humming transformers.

All american equipment (PWD, Spectral etc) in my chain is humming :frowning:

The humming is related to the input voltage (230Vac more humm then 224Vac).

I’ll tryed all kind of filters but i get the the best sound without any kind of filter or generator.

Also phase switching (al equipment connected in phase with the lowest leakage current).

I think it has something todo with the 60Hz component.

American gear is developed for 60Hz main voltage.

Maybe Paul can respond to this!



Hmm, that is terrible for the sound and the noise floor!

Well with the P10 connected as I wrote above the humm is gone.

Without the P10 I have little hum even with the use of other filter equipment!

When the polarity of the P10 is reversed I got Humm off and on with different strenght.



No loss in dynamics!?

Is the power amp also connected to the P10?


@adimon It sounds like you have DC on your line. I don’t think it has anything to do with frequency. The transformers we use just do not hum at 50Hz unless there’s something bad going on the line. The P10 should block any DC which is why wijnand probably does not have hum.


@adimon- An isolation transformer should block the hum if it is DC but it may degrade your sound relative to a more advanced power solution. Might be worth borrowing one if you can swing it, just to diagnose the problem. A check of the line for DC with a VOM would be more practical.

@wijnand- In the U.S., the household voltage is 110v on a three wire system. One (black) is “hot,” the other two are neutral (white) and ground (green). The neutral is connected to the ground at the main junction box so they are functionally equivalent; a safety redundancy. Is Dutch power 220v, “hot” on the two conductors other than ground?

Attached files

No loss in dynamics!?
Is the power amp also connected to the P10?

With the P10 I get the dynamics I never had and yes the poweramp is on the P10. The amp is even havier than the P10, but no trouble at all. It took a while to get the setup right, but it is realy better than ever.


@wijnand- In the U.S., the household voltage is 110v on a three wire system. One (black) is "hot," the other two are neutral (white) and ground (green). The neutral is connected to the ground at the main junction box so they are functionally equivalent; a safety redundancy. Is Dutch power 220v, "hot" on the two conductors other than ground?
It is 230 volts one hot one neutral and one ground. The neutral is connected with the ground at the power transformer a few blocks away.


Wijnand so you are saying you have reversed polarity of cable which is feeding the P10 ?

I guess you had to dissasemble power cord - right ?

Components connected to P10 are all connected by the standard?

I make always sure that all devices connected to audio chain does have the the phase on correct pole but i still have a hum (seems all my EC components hum, Burson amp also hums, but PWD is dead silent…) All except burson are now powered from P5.

On this friday i’m going to upgrade p5 to p10 so i hope it will sove the issue, if not I will try to reverse polarity of cable feeding the P10.



In Holland we use an other wall plug. This one good be plugged two ways.

Which side is the active and the neutral on your P5 sockets seen from behind the at this moment?


It is by our norm - live (phase) on right and neutral on left . Actually the sockets on EU P5 are upside-down (normally should + be on the left side of the socket) :slight_smile:

This produces correct presence of live on EIC cable going from P5 to devices (there is N and L mark on the IEC connectors I have).

This should be correct, right?

I was not experimenting with swapping L/N as my local distributor warned me that all devices connected to P5 should be set in same L/N manner. So from the beginning i’m double checking, measuring and again double checking the setup :slight_smile:



I’m not sure what is wrong or what is right. I am curious if others who have humming equipment also can solve this by changing the polarity of the feeding powercord to the P5 or P10. And if we could make a statement for how to connect the polarity for best results.

For me the PWD has the phase on the lowest pin of the IEC connector (this not for humming but for SQ). For the P10 this is the (phase) pin closest to the middle and the neutral at the side of the P10 (this solves humming equipment connected to the P10 and also for SQ)


@wijnand sorry i’m a bit slowed down today :wink:

when you look to this picture does it correspond to P10 connection to avoid hum?


No for the IEC it is the other way on the P10. This makes the output sockeds active(phase) right and neutral left.