PS10 hum when Lyngdorf RP1 connected

When I run my Lyngdorf RP1 trough my PS audio P10 the P10 makes a hum.
If I leave all other components on the P10, but run the RP straight from the wall the P10 is silent.
Any ideas what could cause this? I assume the fault is on the RP1.
But also looking for similar experiences and possible causes.

Sounds like the Lyngdorf could be introducing DC to the circuit causing the very large toroid transformer in the P10 to vibrate/hum.

Would that mean there is a problem with the lyngdorf?
Or does it works as designed and just not a good combo with the p10?

This would be a problem with the Lyngdorf.

It sounds no more serious than when I complained to my doctor that it hurts when I do this. And he replied, “so don’t do that”.
Plug the Lyngdorf into the wall.


FWIW: I have 2 Lyngdorf RP-1 units and I used one of them with a P15 without any noise from the P15. I now use a DPA-1 preamplifier/room correction/crossover unit also without any extra noise from the P15.

The P15 blocks most of the DC that rides on the home power network, and an A/B power amplifier’s large transformer hums a lot less with the P15.

My P15 hum when nothing is connected to it and it’s using its own power outlet and my AC is turned on on the other side of my house so I think PS Audio stuff likes to hum when you least expect them to. LOL

My P15 hums even more when I put a DC-blocker before it so I don’t think that’s going to make it more silent for you.

Thanks Birger,
At least I feel less lonelly :slightly_smiling_face:

The hum on the P10 is back even without the RP1.
Seems to be the nature of the beast.

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I have the same problem with many of my components connected to the P10.
I think the problem may be less protruding in US (110V/60Hz).
In Norway we have both TN-S and IT net (230VAC):

and I also use DC blockers.
I am struggling with both buzzing and mechanical hum from P10 in my system.
I am not sure if the use of toroid coils are ideal. I have replaced the Dectet because of this.

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Yeah, I have wondered if this is more of an issue in 220v countries. I’m based in Belgium.

I have been looking for the cause of hum in my system for 10 years.

I also had humbusters, but it had 0 impact.

Moved from ppp to p10, both had a hum

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You could be right about the 220-230V powernets. It’s not directly about the voltage but there could be a hum difference due to the frequency difference between the powernets 50 or 60Hz. Large transformers (even high quality transformers) hum easily which is annoying for audio. A transformer on 60Hz is more efficient than a transformer on 50Hz. Besides this you need more windings (more copper) to transform from 230V to for example 12V then you would need when you transform from 110 to 12V.

To solve the problem with hum on large transformers is the use of more smaller transformers in parallel.

Yep … interesting follow up : does it make sense to buy american (or 110v) equipment if you’re in a 220v country? Do you get max performance out of it?

The lyngdorf has a voltage switch. Their stock power cords stock have ferrite bead blocks. I wonder if the hum worse if you use other than stock cords?


I hope Paul steps in and make some kind of suggestion.
A lot of PSAudio users claim to hear hum in their products and this is not a fault in their AC line (there is no relevant DC or other type of nasties). I have had 2x PPP , one hummed more than the other. I replaced them with a P10, that also hums.
In my previous apartment the P10 was located in a place where the hum was inaudible from the listening position so i did not bother.
In my NEW house, the P10 is directly located in front of listening position and i can hear the hum. It is so annoying that i turned the P10 OFF ! I am now contemplating on how to silent it before i plug it in back in the system, or it will have to go .

This is mainly for Paul : can we open the P10 and encapsulate the Toroid in a pot with resin ? If yes, what do you recommend for poting ? Why is it not potted in the first place ?

IF one chooses to replace the toroid with a custom new one, can you share the specs ?
Cheers all
Hope to fix my P10

The first thing to do, IMO, is to turn the MW completely Off (use Sine).
This may help a little.

At least for me, the solution was to turn Off the PS10 completely.
I am still waiting for Paul to help me identifying the best way to shut the toroid up, or if i can buy an aftermarket one , designed to spec.

I must say, i was hoping to get some feedback here from PS Audio. I did not.

So i want to share my experience with my P10.
It as humming (50Hz hum) from the start with nothing connected. No filter was able to remove the hum and no setting applied. This had to do with the toroid itself, as its a large toroid, it hums. They all do.
To prevent the hum to spread to the chassis and become audible, some builders use techniques like potting and resign filling on the toroid. PS Audio used centre filling on its toroid. It was just not enough.

My take : I went ahead and found a 160mm aluminium pot, and inserted the toroid in it, with resign epoxy from Robnor. Its a special resign non conductive, but thermally permeable.
I also used some sound deadning sheet (for car applications) on the bottom plate and top plate of the chassis to make sure nothing vibrates.

I can assure you, my P10 is now dead silent and i cannot hear the hum anymore.

So my advice would be to PS Audio to make sure the toroids are in fact better sealed.
Giant toroids like this hum, and in some rooms it is audible and very annoying.

All the best to you, i can now use my P10 again, thanks to me, not PSAudio.

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Nice work. Sorry we didn’t really have anything to add to the discussion. Indeed, some toroids and transformers are hum prone. We deal with that for many years and did things like you: potted them, encased them, etc. It wasn’t until years later we found a toroid
manufacturer that knew how to make dead quiet transformers that we solved the problem. Now, we just have to install the transformers and no more hum. But that took 20 or so years to find the right vendor.

The Toroid on my P10 is a NORATEL with resin filled center.
Are you saying you changed manufacturer and no longer use these ?
I would assume NORATEL would build you the toroid encapsulated with whatever you would want ?

My P15 hums also and it’s easy to hear it 20 feets away, if the room is quite.