QED PROFILE Audio RCA to RCA – 3 m

The QED Profile RCA to RCA cable in its 3 metre length is a stereo analogue interconnect with two phono plugs at each end. Three metres is the length that covers the common situation where the source and the amplifier are not in the same rack: a turntable or streamer on a sideboard, an amplifier on the floor between the speakers, or a subwoofer positioned in a corner away from the electronics.

An interconnect carries a line-level signal, which means a fraction of a volt and almost no current. That has an important consequence: unlike a speaker cable, its conductor cross-section is largely irrelevant to the result, while its shielding is decisive. The signal is small enough that mains hum or radio frequency energy coupling into the cable is a real and audible risk, and the screen is what prevents it.

The 3 metre length is also long enough to make routing worth a moment's thought. Keep the interconnect physically separated from mains leads and from switch-mode power supplies, and where a crossing cannot be avoided, cross at ninety degrees rather than running alongside. If there is surplus cable, lay it in a loose S rather than winding it into a coil.

One further point applies specifically to systems with a mixture of grounded and floating equipment. If a hum appears only when this cable is connected, the cause is almost always an earth loop through the system rather than the cable itself, and the cure lies in the equipment's earthing arrangement, not in a different interconnect.