P3 programmed sockets odd behaviour

Hi All,

New to this, please apologize if this was asked, but I could’t find any more information on this.

I have recently acquired an ex-demo P3 for few reasons, one was to have programmed socket control and, obviously, some mains filtration. I actually have question on both…

My setup is nothing extraordinary, built and modified over years, but is quite reveiling. CEC TL51 CD player -> Unison Research Mystery One valve preamp -> Marantz MA5 monoblocks -> KEF reference 201/1 speakers. Components are DC coupled.

Due to DC coupling, I always had to power up the preamp first and give it a minute or so to settle down before powering up monoblocks to avoid a loud thump through speakers. The P3 gives an option to have a programmed / delayed power on/off of each power outlet, configurable via web interface. So I did that.

I’ve set power on to delay certain sockets by 60 seconds. All good.

Powering off requires me to power off monoblocks first, then the preamp and the rest. So I’ve set to delay preamp turn off by 10 seconds. Which works, kinda. What happens is, when I power off the P3, all sockets go off immediately and a second later they all power on again and then 10 second delay kicks in. What a mess! Any advice is highly appreciated.

Now on power regeneration. I feed everything through the P3, which takes about 130W all in. I do notice, that the system has a good deal of reduction in dynamic range, yet it sounds ok. So I tried reversing power sockets, which did make the sound top end more extended and what seems more impactful (can’t say brighter), but way too sterile or analytical somehow fatiguing ears after a while. I have a choice of other 2 passive preamps, TVC and LDR controlled, but they only slightly tweaked this and that of the spectrum, but the listening is still intense… I wonder if this is more of burn-in question or this sound signature will remain? What’s your experience?

Apologies for a rather long post, thanks in advance!


Hi Art,

Thanks for reaching out. Can you send me an email to jamesh@psaudio.com with the P3’s unit ID?

I want to look at it in PowerPlay, and see if I can find any odd behavior.



Maybe some additional run in is needed, but I suggest you try connecting your amp to the “HC” outlet.

I found my P3 works great with source components, but my M60s sounded better through the high current pass through outlet.

They only drew 190 watts, I think the reduction in sound quality may have to do with the amps and the output impedance of the regenerated outlets.

Jamesh, MrDerrick,

Thanks for replies.

Connecting unit to the internet is no possible due to device locations. I could only access the internal page bringing the router closer to the unit, but it had to be disconnected from the internet.

Luckily enough, the issue with sockets has been fixed by flashing the unit to 0.15 from, what it seems, 0.11 or 0.12. It is now powering off correctly. Phew.

I have to say, sound wise, it got a lot better after few days running it, lot more body in it. Curiously it is no longer taking 130W, but 120W for some reason. I have also shortened the power cable and took fuses out. I know it is at my own risk, but impact to sound fuseless system does is quite noticeable, especially in UK type plugs, where fuse is excessively present in every device and also plug. Essentially reducing supply impedance… Also P3 seems to like it better with mains plug polarity reversed (when measuring AC of chassis to socket ground, ground lifted).

The only thing slightly bothering me is the audible buzz from the unit’s stand-by circuit, I may need to open it and see where it comes from.

Otherwise, think I’m good for now.

Thanks again guys.

My P3 also buzzes, and it is quite audible when everything is in standby. I’m not sure what you hope to achieve by opening it. I think lifting the ground on a 240V P3 and messing with polarity (swapping L and N at the input) is unwise.

It’s good to know the buzz is not just in my unit, pretty normal then. Sounds like a strained transformer. Was hoping I can dampen it, but you may be right, if it is a loosely wound transformer, then not much can be done other than, perhaps, impregnating it or reducing the load.

I don’t encourage to change anything in the system from standard, just shared my observations.