Most of us need to use a mains extension to connect our system to the wall socket. Extensive testing has shown us that ordinary extension blocks can degrade the sound of your system – factors such as build quality, the materials used and the design of the cable attached will have an impact on the sound, for example, by having poor contacts that increase impedance.

This article looks at how we address these issues by examining each of the different elements that make up our mains extensions.
 

SocketsUltraSocket image

One of the most important parts of a mains extension are the sockets that your cables plug into. The material the contacts are made from, the plating material (if any) used on those contacts, and how they grip the plug pins are all important. Whether they are switched or not also has a bearing on the sound.

The most common types of sockets that we supply in our extensions are the UK 13A type: we can also supply the European ‘Schuko’ and US type for customers outside the UK.

Traditionally, the performance of UK plugs and sockets has lagged behind that of the Euro and US equivalents, but in recent years the new AQ mains plugs and the new sockets we’ve been using in our extensions has lifted the performance of these plugs and sockets for those of us in the UK.

We use three different types of sockets on our UK mains blocks – good quality outlets used in the PowerBars™ which feature copper alloy contacts; higher performance UltraSockets™, used in the X-Blocks™, which feature a higher contact connection and nickel plated earth terminals - along with Deep Cryogenic Treatment (DCT); and our very best Audio Quality Signature™ sockets in the Signature PowerBlock™, which are rhodium plated throughout and treated with our exclusive Process Q™.

None of the sockets feature switches – we have found that switches degrade performance by increasing the mains impedance.

WiringInternal wiring

The way the sockets are linked together in the extension is also an important consideration. Our extensions have sockets that are connected with wire as opposed to metal busbars, which are used in some other extensions: we have access to high performance wire (including some of Kimber’s internal wire made specifically for these sort of applications) and special processes to ensure a low-impedance connection.

Our very best block – the Signature PowerBlock™ – also uses an innovative internal distribution circuit to ensure identical current delivery to each of the sockets.
 
A note on ‘star wiring’

Star wiring refers to the process of wiring each socket individually to avoid any minor output variance between sockets. All things being equal, this is a good thing. However, all things never are equal and there are other factors which need to be taken into consideration.

The major one is cost: to star wire each socket practically doubles the amount of wire used. With a high-end product this is not so much of an issue – our Signature PowerBlock is star wired, for example - but with budget to mid-range items this additional cost will need to be balanced by a compromise somewhere else. An obvious option would be to use cheaper wire but in our experience the use of better-quality wire far outweighs the advantage of star wiring.

And that’s fundamentally why we don’t star wire our PowerBars and X Blocks. There’s a choice: either the price of the extension has to be increased to reflect the cost or the cost has to be reduced by lowering quality somewhere else. Both PowerBars and X Blocks have been designed to maximise the performance for the cost, primarily by using the highest quality parts for the budget. In our experience, the performance benefits of these parts far outweigh the advantage of star wiring.

Surge protection and power conditioning

It makes sense to combine surge protection with the block - it offers both a level of protection for your system and has performance benefits too. The components are fitted internally which means that all outlets benefit and you are not using up a socket plugging in a stand-alone SuperClamp™ or MegaClamp™.

SuperClamps™ are an optional extra on the PowerBar™; they are fitted as standard in the XBlocks™. To maintain performance, we recommend refurbishment of SuperClamp™ components every five years - contact us for details.

The MegaClamp™ is standard on the Signature PowerBlock™.

X-Blocks™ also benefit from our Silencer™ mains filter (though a non-filtered X-Block™ is available to special order if, for example, you want to use the X-Block™ in conjunction with Balanced Mains).

The Signature PowerBlock™ does not feature any filtering other than the MegaClamp™; it is designed to be used with the stand-alone PowerPurifier™ which brings together all of the different filtering devices in a convenient unit and can be plugged into the block.

Connecting to the wall socketIEC Socket

Clearly, the connection of your mains extension to the wall socket is important too. All our extensions are fitted with an input socket and not supplied with a cable; this allows you to choose the best cable type and length to suit you and your system.

A standard IEC socket is fitted to the PowerBar™ and X-Blocks™, and the better-performing 16A high current IEC socket is fitted to the Signature PowerBlock™.

Our extensions have been designed to work at their best when fitted with any of our RFI-cancelling woven power cables – from the yellO Power™ to PowerKords™ and SuperKords™.

Any of them will work well, but as a guide PowerBars are most often partnered with yellOs or Evolution-100 PowerKords™; X-Blocks™ with Evolution-100 and Evolution-300 PowerKords™; and Signature PowerBlocks™ with Evolution-500 PowerKords™ and EVO-S PowerKords™.
 
Why lowering impedance is important

Impedance is the resistance to an alternating current. Although Hi-Fi systems have relatively low current demands, it’s important to allow your system to draw the current it needs from the mains to ensure good bass performance and treble sweetness. A modest Hi-Fi amplifier can easily demand 100 amps from the mains for a millisecond on loud drum transients!

If current delivery to your Hi-Fi system is impeded, the result can be a flat, two-dimensional soundstage with poor bass and treble. One of the design goals of our mains extensions is to keep impedance low – we achieve this with high contact, un-switched sockets (switches increase impedance) and high quality internal cabling.

One way to maintain low impedance is to keep your contacts clean, as oxidised contacts can increase it. This is easily achieved by cleaning with DeoxIT contact enhancer every three–six months. Find out more about DeoxIT.

Extension capacity & 'Star Powering'Star Powering

We’re often asked whether plugging a full Hi-Fi system into one of our mains extensions will overload it, and if it’s safe to do so. The simple answer is yes, it’s perfectly safe. All of our mains extensions are designed to deal with much higher current levels than you will ever get in a domestic Hi-Fi system.

We measured (relatively power-hungry) Quad system comprising a CD player, turntable, tuner, tape deck, preamp and two valve power amps and found that it drew just over 1A amp when running. You could easily power TEN such systems from one of our mains extensions and you still wouldn’t reach the rating of the extension.

Our power cables and extensions are all rated at 13A and there is a huge margin built in for safety. And it actually makes good sense to connect all of your Hi-Fi components in your Hi-Fi into an single extension – as well as being neat and convenient, using an extension block means that your system is connected to your mains circuit at a single point. We’ve found that this sounds better than connecting your system’s mains leads to several wall sockets at different points of the mains circuit.

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