QED Signature Audio 40 RCA Interconnect (0.6m Pair)

The Signature Audio 40 sits at the top of QED's three-tier Audio 40 analogue interconnect range, above the Performance Audio 40i and Reference Audio 40. Developed to mark QED's 40th anniversary as a British cable manufacturer, the design focuses on a single engineering priority: minimising capacitance across the signal path to preserve timing and recover fine detail from a two-channel source.

Construction

The conductors are silver-plated 99.999% oxygen-free copper (SPOFC), high-purity copper with silver plating for improved high-frequency transmission. The dielectric is PTFE (Teflon), chosen for its low dielectric constant, which limits signal energy lost to cable capacitance across the audio band. Capacitance measures 63 pF/m, inductance 0.37 µH/m, and loop resistance 0.072 Ω/m.

The geometry is an asymmetrical twisted pair, which is the basis of QED's Complementary Conductor Technology. Two conductors of deliberately different diameters carry the same signal simultaneously. High-frequency components tend to favour the thinner conductor due to the skin effect, providing an alternative pathway and reducing the time-smearing that occurs when all frequencies share a single conductor.

Shielding

Electromagnetic interference is addressed in three layers. An SPOFC braid provides 100% electromagnetic coverage around the signal conductors. Inside that sits an aluminium wrap for additional broadband screening. The outer jacket is a PVC compound loaded with zinc/manganese ferrite, a material that absorbs high-frequency interference rather than reflecting it back.

Cryogenic treatment

The complete cable assembly is cryogenically treated at temperatures below −190°C. QED states that deep cryogenic treatment eliminates dislocations and fractures in the copper's micro-structure, and their listening tests consistently favour the treated cable over an otherwise identical untreated version.

Analoc2 connectors

The Analoc2 RCA plug is a QED-designed connector developed specifically for the Audio 40 range. The signal pin is hollow and rhodium-plated: the hollow construction reduces mass and addresses skin effect at high frequencies, while rhodium provides a hard, corrosion-resistant contact surface. The plug body uses high-rigidity thermoplastic rather than metal for both the inner support structure and the collar, eliminating eddy current distortions associated with metallic connector bodies. The ground connection is made via a dual-blade arrangement that increases contact area, and a locking slip ring on the barrel tightens the blades against the socket as the plug is secured, improving both ground continuity and mechanical stability.

At 0.6 m, this is the shortest option in the Signature Audio 40 range, suited to systems where the source and amplifier sit close together on the same rack.