QED Supremus Zr Speaker Cable (2m Pair)

The Supremus Zr is QED’s flagship loudspeaker cable, sitting at the pinnacle of the Signature range above the Genesis Silver Spiral and Golden Anniversary XT. Developed without compromise, it represents more than five decades of technological evolution and refinement in cable engineering, designed to bring the amplifier electrically closer to the loudspeakers and enable tighter control over the drive units.

Aircore Construction

At the heart of the Supremus Zr lies QED’s Aircore technology. Thirty-two solid-core conductors are arranged in a twisted spiral around a hollow central tube, a geometry that minimises skin effect by ensuring each conductor carries a proportionally equal share of the signal. The spiral construction, combined with polyester insulation, also reduces the proximity effect — the tendency for current distribution within adjacent conductors to become uneven at higher frequencies. The result is more uniform signal transfer across the full audio bandwidth.

Conductor Specification

Each of the 32 conductors is silver-plated, 99.999% oxygen-free, polyester-coated copper. The combined cross-sectional area of 6.2 mm² (10 AWG) delivers an extremely low loop resistance of just 0.005 Ω/m, making the cable particularly well suited to long cable runs or systems where maintaining amplifier damping factor is critical. The dielectric uses a combination of foamed polyethylene, LDPE, and air — materials chosen for their low dielectric absorption characteristics.

Cryogenic Treatment

The copper core undergoes deep cryogenic treatment, a process QED states improves the microstructure of the copper by eliminating crystalline dislocations. This results in a more homogeneous conductor structure with fewer grain boundaries for the signal to traverse.

Zirconia Plugs & Airloc Termination

The ‘Zr’ designation refers to the plug barrels and boots, which are machined from zirconia — an advanced ceramic chosen for its durability and resistance to performance-affecting eddy currents. The rhodium-plated beryllium copper banana plugs use QED’s Airloc cold-weld termination system: a high-pressure process that compresses the conductors and plug together, creating a cold-welded joint where conductors and plug effectively become one. Because all air is removed from the joint, there can be no oxidisation or degradation in conductivity over time. The locking mechanism securely clamps the rhodium-plated pins into the speaker terminals, and the very smooth rhodium surface increases the contact area, further reducing resistance.

Designed & Engineered in the UK

QED has been designing and manufacturing cables in the United Kingdom for over fifty years. The Supremus Zr carries the inscription “Designed and Engineered in the United Kingdom” on its outer sheath.