Mains extension blocks


You g1t !!! I didn’t think of the cooker. Now you’ve spoilt my day as we too have one of those.
The kitchen is on the same ring as the NAS/router/switch etc. Odd, but true - our 3rd bedroom (estate agent description of a 6ft x 6ft upstairs room) is on the kitchen ring (the kitchen is directly below the circuitry room* as estate agents don’t call it) - not sure how clever that is, but that’s the only place it all fits without taking over the lounge.

…fret, fret, fret…

*As in Voyage to the Bottom of the Sea


The cooker should normally be on its own circuit rather than the kitchen ring, which might give you some small comfort.


Actually, yes it is, forgot about that - but the microwave and fridge are on the kitchen ring, or the computer ring as it is more accurately named.


Tried the AM test, the Hicap DR was one of the worst offenders in the room (apart from wifi, etc.), beaten only by a non-Naim PSU…


You sure about that…


Yes - but I did say apart from wifi, etc.


Ok but it’s a linear power supply. It shouldn’t radiate HF noise.


Could it be something to do with the mains ? It also hums quite a bit.


Could be - disconnect the hicap from the mains and place the radio close to the mains lead. Looks like you might find something else generating noise.


OK, I’ll try that tomorrow, thanks.


Also make sure the mains lead is connected securely. Simon, is it possible that arcing might be the cause of the issue?


I haven’t done the AM radio test but just by taking measures to turn off unnecessary devices and move others I can tell that there has been a SQ improvement. My list started with a Eon smart meter monitor, a WiFi surveillance camera and Apple TV. I have turned of the Panasonic Blu-ray player and theHumax Satellite box is left on standby more rather than being used as a convenience.

I think the Eon monitor uses the limited internal battery (15 minutes capacity) and then charges. I suspect it may have been the worst offender. SQ now seems consistent.

I have replaced two surge protected mai s blocks.



James, a linear powersupply can radiate noise, especially if the transformer becomes saturated with DC on the mains…


Good point - even in saturation I would have thought any high order harmonics would still be at a low enough frequency not to cause issues. What are you thinking Simon ?


James, sure the harmonics almost certainly won’t be as extended as a bad SMPS, but electromagnetic noise will still be more evident.
The saving grace is that smaller frame transformers are less efficient, which means they are less likely to saturate and buzz, so be better behaved from an electrical noise perspective.


Found 1 pic of my block, without the fully isolated carbon fibre back fitted. Surely if you’re looking at one grand purchases, you wouldn’t be better off spending your money/time on making your own?


Is the mains lead that comes with a 272 a Powerline Lite. Or would a Powerline Lite be an upgrade on the stock 272 lead?


I’m afraid I don’t know, but if it looks like this…

…then it’s a Powerline Lite, which is an upgrade over the standard UK mains lead.


Yes it looks just like that.


In the UK, the Powerline Lite is now the standard mains lead, so you get one with all products.