QED XT25 Performance Speaker / HiFi / Cinema Cable 1x 2 Metre
Terminated with QED ABS Banana Plugs
Using Airloc Technology on ALL Banana Plugs
(You are buying 1x 2 Metre cable with 2 QED ABS Forte Plugs on each end of the cable)
(Please put “ 2 “ in the quantity section, if you are wanting a pair of cables)
The multi-award winning Silver Anniversary XT cable delivers superior performance for all your hi-fi and reference home theatre needs
A REPUTATION FOR EXCELLENCE
QED has an extensive range of high-quality products from entry level to high-end cables. Learn more about QED cable technologies.
X-Tube Technology
Calculation can accurately predict the maximum skin depth at a given frequency for a particular conducting material making it possible to keep the diameter of the cables below the critical size determined by the maximum frequency expected.
QED cables above 1.5 mm2 cross-sectional area utilize air core technology to obviate the skin effect by bundling several smaller cores together to make up a larger CSA.
As frequency increases electrons flow more and more towards the periphery of a conductor so that if the frequency is high enough only a very thin layer (or skin) on the outside of the conductor is used.
This skin depth varies for different materials at a fixed frequency and in copper it means that if a conductor has larger than 0.66 mm2 cross-sectional area not all of that area is available for an analogue music signal to use.
In previous QED cables the skin effect problem was effectively eliminated by the use of X-Tube™ Technology which works by placing all of the conducting material around a central hollow insulating rod.
However, for ac signals, changing magnetic fields generated by the flow of current set up eddy currents in nearby conductors which force current to flow only in areas furthest away from conductors carrying current in the same direction and vice versa.
This proximity effect has a detrimental influence on current distribution in a speaker cable even if it utilises X-Tube™ Technology.
With XT25, QED’s engineers tackled the proximity effect and the skin effect by combining QED’sexisting Aircore™ and X-Tube™ technologies.
Air Core Technology
In loudspeaker cables electrical current does not flow smoothly because - rather like in a river - small eddy currents are formed.
Eddy currents in one conductor can affect the current flowing in an adjacent conductor so that currents flowing in the same direction move away from each other.
This "Proximity Effect" increases resistance as frequency increases which has a detrimental effect on the fidelity of the sound you hear.
QED Aircore Technology builds on the science of X-Tube Technology and eliminates this problem by using individually insulated twisted strands arranged around a hollow core to solve both the proximity and skin effects.
What is Airloc™?
Airloc™ is a form of cold weld system that permanently attaches QED Forté™ banana plugs to our entire range of speaker cables.
One of the main reasons for choosing a QED speaker cable is the superior d.c. resistance characteristics offered by our exclusive use of 99.999% oxygen free copper conductors.
It seems a shame then to ruin all this attention to detail by neglecting the most vulnerable area of the speaker cable chain - that of the physical interface between cable and amplifier or speaker terminals.
Seen under a microscope the surface of a typical copper strand is very rough and so using normal screw type terminals - such as found on binding posts or cheap banana plugs - electrical contact is only made in a relatively small number of places.
Add to this a layer of oxidation - which is inevitable if copper is exposed to the air for even a short time - and the combined resistance of the cable and its termination can creep back up to levels present in a more inferior cable.
By using a cold weld crimp type termination Airloc plugs squash the conductors and plug together to improve contact area and reduce resistance.
As can be seen in the graph, by the time the full pressure has been applied the resistance of the joint has reached a minimum value.
Now, because all the air has been removed from the joint there will be no oxidisation of the contact surfaces either so the low resistance will remain for the lifetime of the cable. During the cold weld process the cable and plug become one solid piece of metal.
Since the copper contact has been effectively removed from the resistance equation we can concentrate on the plug to terminal resistance.
If a bare wire termination method is used the exposed copper quickly oxidizes increasing the resistance of the cable, which has a detrimental effect on the fidelity of the sound you hear.
Available as an option, QED Airloc plugs eliminate this problem by preventing oxidization and providing a gold plated mating surface which remains low resistance for ever.
What are Forté™ Plugs?
The plugs themselves are made of solid brass which has roughly twice the resistivity of copper.
For this reason our 4mm banana plug was devised so that its cross sectional area would be at least double that of the cable to which it was connected effectively cancelling out the extra resistance of the plug material.
QED then plates the connector with high purity gold which has a resistivity almost as low as copper but more importantly does not oxidise in air.
The relatively smooth gold surfaces provide a larger contact area than the uneven copper strands in the cable and because the gold will never oxidise the contact surface remains clean and low resistance for life.
The new Forté plug pin section is designed to maximise contact area throughout the wide tolerance range encountered in 4mm amplifier and speaker sockets.
Here some are quite tight whereas others are loose, so the spring loaded Forte blade is designed to fit into smaller and larger sockets with equal insertion force.
This means that the contact area is maximised and the connection remains uniformly tight.
QED Forté with Airloc technology
guaranteed low resistance and strength - for life.
Low DC Resistance – 2.5 mm2
QED have long recognised that low DC resistance of the loudspeaker cable is of paramount importance for high fidelity signal transfer.
This is because the speaker presents a frequency dependent load to the amplifier of which the cable forms a variable proportion.
If resistance is allowed to be too large, then audible changes to the frequency response characteristics of the loudspeaker will be introduced which cannot be corrected for by the amplifier’s negative feedback loop.
In order to improve upon previous budget cables, QED’s first target was to increase the CSA without increasing the overall size of the cable substantially.
To that end, combined with QED’s exclusive use of 99.999% oxygen-free copper, the CSA has been increased from 1.5 mm2 to 2.5 mm2 which instantly gives the new cable a considerably lower dc resistance and therefore a higher fidelity musical delivery.
Low Loss Dielectric
It is not generally appreciated that the electrical signals moving at or near the speed of light in a wire do so via the medium of electromagnetic (EM) waveforms which exist within the dielectric which surrounds the conductors as well as within the conductors themselves.
The movement of electrons along the conductor merely facilitates generation of the EM waveform as their drift velocity is much slower - being only a few centimetres per second.
It is therefore important to ensure that the dielectric material used to insulate and protect the central conductors of the speaker cable is of a type which ‘permits’ the establishment of EM waveforms without appreciable loss.
Dielectric losses are directly proportional to the permittivity of the material used and as this a measure of each material relative to that in a vacuum it should be as close to unity as possible.
Like its predecessors, XT25 uses a specially formulated low-density polyethylene (LDPE) dielectric which at 1.69 has the lowest relative permittivity practically available.
QED’s research has shown that low capacitance cables are generally preferred in listening tests over high capacitance counterparts and this is usually because low loss dielectrics have been utilised.
The use of LDPE and careful control of conductor spacing results in a cable with a very low capacitance per meter and a dissipation factor (loss tangent) of 0.0001 at 10 kHz
99.999% Oxygen Free Copper
Speaker cables have to carry a lot of current. If the electrical resistance of the cable is too large, part of the music signal will be lost, causing a detrimental effect on the fidelity of the sound you hear.
To stop this from happening QED makes the resistance of their speaker cables as small as possible. This is done by using the largest practical cross-sectional area of copper within the size constraints of each cable.
In order to squeeze the last drop of performance from the conductors QED make sure that there are no impurities in the copper which would defeat the object of making them so large.
That’s why they use 99.999% oxygen free copper exclusively.
What is the result of all these improvements?
The graph below shows how the dc resistance of XT25 remains effectively unchanged across the entire audible frequency band when compared to an ordinary cable of the same cross-sectional area.
Combined with the sonic advantages of a low loss dielectric these improvements place the new cable in a unique position to rival its own illustrious stable mate.
QED, unlimited lifetime guarantee
Unlike most other manufacturers QED offer an unlimited lifetime guarantee
SPECIFICATIONS
K6Believes
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Domestic Shipping
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International Shipping
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This has been recommended for its costs and efficiency for both ourselves and you the Customer.
These items will be sent to a Global Shipping Programme (GSP) depot in the UK by ourselves, then the GSP will then take over the shipping process.
(if Size or Weight allows, we will try our best to bundle items together if ordered in separate transactions)