X4 Block MKII UK

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    X-Block MK.II

  • Superb value, high-performance audio-grade mains extension

  • NEW Ground terminal & 10A IEC mains output socket

  • Features Russ Andrews UltraSockets™ treated with DCT and DeoxIT®

  • Internally wired with Kimber Kable® TCX™ cable

  • Incorporates Russ Andrews Silencer™ mains filter and SuperClamp™ for mains noise reduction

Why X Blocks™?

Designed and built by us, X-Block™ mains extensions use our superb UltraSockets™, are wired throughout with Kimber Kable® and are fitted with our Silencer™ mains filter and SuperClamp™ surge protection. The MK.II version adds additional functionality in the form of a Ground Terminal to allow integration with our grounding ecosystem. The second improvement is a 10 IEC output allowing the connection of a second block or component.

Bettered only by our Signature PowerBlock™, X-Blocks are our best value mains extensions and can be used in a vast range of systems; from a small CD/amp, to a high-end system comprising up to eight separate components.

X Blocks are hand built to exacting standards by our highly-skilled manufacturing team and are guaranteed* to provide a lifetime of listening enjoyment.

    X-Block MK.II additions

    The X2, X4 and X6 Blocks now incorporate a ground terminal, which is useful if you want to use it with the Russ Andrews Grounding System. It can be used in a couple of ways – you could use the ground terminal on the X-Blocks as a way of connecting an RF Router or SuperRouter to earth – simply link the output of the Router to the terminal on the X-Block. This is a simple way of implementing our grounding if you are not able to install an external earth rod.

    If your Grounding System features an external earth rod, you can get great results by integrating the X-Block. Using Technical Ground Weave, connect from the terminal to a terminal on the Router.

    The second update adds an output IEC socket to the end of the X-Block which allows you to daisy-chain an additional mains extension. It’s useful if your system has grown in size and you have run out of sockets.

    Another use is to use the output socket to connect a mains filter, such as an AbZorber or Power Purifier which means you aren’t using one of the 13A sockets on the X-Block.

    Example of the new feature in use.

    X Block MK.II features

    • 2, 4, or 6 UltraSockets™. X Blocks are fitted with our superb, high-performance power sockets to ensure the very best connection. UltraSockets have a very high build quality and, for good measure, every UltraSocket is Deep Cryogenically Treated and treated with DeoxIT® contact enhancer.

    • Kimber internal wiring. We only use Kimber’s high purity TCX™ copper cable for wiring X Blocks. This ensures full performance is maintained throughout the block with minimum impedance – each socket is optimised so there’s no restriction on where high-power components can be plugged in.

    • Bespoke ABS anti-shatter casework. We use ABS because of its combination of strength, rigidity and acoustic neutrality. It also keeps the pound-to-pleasure ratio high too!

    • Silencer™ filtration. Each X Block is fitted with our highly-rated Silencer mains filter to reduce mains noise interference. It works passively, meaning that it has none of the drawbacks of many other mains filters – drawbacks such as loss of musicality and reduced dynamic range. It’s wide-band too, effective at filtering over a wide frequency range. For the techies amongst you, it is a 'passive differential and common mode inductorless non-resonant harmonic filter'!

    • Ground Terminal. Each block is fitted with a grounding terminal, to allow you to add an additional ground to your Hi-Fi system in conjunction with our RF Router™. The high performance, nickel plated terminal accepts cut & stripped wire, a 4mm Banana and 6mm spades.

    • SuperClamp™ spike and surge protection. SuperClamps not only offer protection for your system, they also bring sonic benefits by addressing minor spikes and surges that appear on the mains on a regular basis. In our opinion, these high voltage spikes can raise the background noise level in amplification circuits which is why it makes good sense to try and reduce them.

      We recommend factory replacement of all SuperClamp components every five years to maintain their effectiveness - click here to read more.

    • 10A IEC Input socket. X Blocks are fitted with a 10A IEC socket, allowing you to choose the level of mains cable you desire. We recommend a minimum of the Evolution-100 PowerKord™

    • 10A IEC Output socket. MK.II X-Blocks have an additional mains outlet at the other end of the case from the mains inlet. This allows you to daisy chain a second block (to extend the number of sockets) or to attach a mains filter such as our PowerPurifier™. The outlet is a 10A female outlet socket. We make special IEC to IEC cables to utlise this connection.

    • Need more sockets?

      Click here for the X8
      (not currently available in MK.II specification).

      Money Back Guarantee

      Don't forget! We are so confident in the performance of this product that it is covered by our 60 Day Home Trial with Money Back Guarantee. Buy the product and if you're not completely satisfied, you can return it within 2 months for a refund.

      For full details click here.

      Upgrade Scheme

      You can upgrade to the X6 Block (and get up to 100% of the original cost of your upgrade back) from any of the following:
      PowerBar 4-way, PowerBar 6-way, all PowerLinks, all SilencerBlocks and all YellO extensions. Sorry, but you cannot upgrade an original X-Block to the X-Block MKII.
      For full details of our Upgrade Scheme, click here.


      6 UltraSocket™ outlets, treated with DCT and DeoxIT®

      Wired with Kimber TCX™ cable

      Russ Andrews Silencer™ mains filter

      Russ Andrews SuperClamp™ surge filter

      10A IEC mains socket allows you to connect your choice of mains cable (not supplied)

      Impact and fire resistant ABS casework

      High performance Ground Terminal

      10A IEC Female Output socket


      The 2, 4 and 6 way Height and Depth dimensions of the X-BLOCKS are the same, only the length differs. Length includes Ground Terminal. The height includes the feet and sockets.Height: 65mm
      Width: 85mm

      2 way length: 190mm

      4 way length: 310mm

      6 way length: 430mm

      Please note that X-Blocks do not include a mains cable - we recommend a minimum of our YellOPower and ideally an Evolution-100 PowerKord or better; click here for details


Currently the X8 is not available in the MK.II specification but is shown here for comparison. We hope to introduce the MK.II modifications later in 2024.

8 way length: 525mm


"By allowing your electronics to give their best, this mains block is worth every penny"

Read more about the What Hi-Fi review here

[allows your system] "to truly perform as it should without sounding held back... recommended without hesitation"

Read more about the What Hi-Fi review here

"will provide an enhanced performance for any hi-fi"

Read more about theaudiophileman.com review here

"worked very effectively, giving a smoother and more relaxed sound"

Read more about the Hi-Fi Choice review here

Customer Reviews
Overall product rating 0 / 5