A player with only RCA outputs paired with an amplifier that only accepts XLR, or a balanced cable you would like to keep using with an unbalanced input: as a system evolves, the two standards often end up crossing paths. Cardas hand-assembles a pair of adapters that bridges the two worlds in its workshop in Bandon (Oregon). Each adapter pairs a Neutrik XLR plug with an RCA connector made by the brand itself.
A Neutrik plug and a Cardas connector
On the XLR side, Cardas turns to Neutrik, a Swiss manufacturer whose plugs are the professional industry’s benchmark for mechanical strength and locking security. On the RCA side, the connector comes from the Cardas workshops. Its body is made of brass with a high copper content, a non-magnetic alloy: there is no ferrous metal in the signal path. The contact surfaces are silver-plated with a rhodium coating. Silver conducts electricity very well, while rhodium, a hard metal in the platinum family, protects it from oxidation and wear caused by repeated connections. Inside, the two plugs are connected using the brand’s internal hookup wire and soldered with Quad-Eutectic alloy, an in-house solder with a low melting point.
Four configurations depending on the connection direction
A male plug carries the pins or center pin, while a female plug receives them. The adapter comes in four combinations: female RCA to male XLR, female RCA to female XLR, male RCA to male XLR, and male RCA to female XLR. To choose, simply look at what will plug into each side. A female RCA to male XLR version, for example, receives the end of an RCA cable and plugs directly into an amplifier’s XLR input. A male RCA to female XLR version does the reverse: it plugs into an RCA socket and accepts the male plug of an XLR cable.
Internal wiring of the XLR pins
An XLR socket has three pins: pin 1 for ground, pin 2 for the signal, and pin 3 for an inverted copy of that signal. An RCA connector has only two contacts, the center pin and the ground ring. In the Cardas adapter, pin 2 connects to the center pin and pin 1 to the RCA ground. Pin 3 is connected to ground on three of the four versions. On the female RCA to female XLR version, it is left floating, with no connection.
This conversion has consequences worth knowing about. The connection becomes unbalanced, and the interference rejection inherent in an end-to-end XLR connection is lost. When a device with an XLR output feeds an RCA input, only half of the balanced signal is used, resulting in a level around 6 dB lower: simply turn the volume up a little. Finally, connecting pin 3 of a balanced output to ground poses no problem for most devices, but some output circuits do not tolerate it well. The source device’s manual remains the best way to check.
Adapter or dedicated cable, depending on the installation’s duration
Cardas itself recommends reserving its adapters for temporary use: testing a device, troubleshooting, or a temporary setup. If the RCA/XLR pairing is to last, an interconnect cable terminated with RCA at one end and XLR at the other avoids two additional contact points, and all Cardas interconnect cables can be ordered in this form. The brand also points out that a device with RCA sockets for both outputs and inputs is best kept connected via RCA: using an adapter to connect to an XLR input offers no benefit. Weight must also be taken into account. An XLR plug and its cable weigh more than a simple RCA plug, and the assembly acts as a lever on the device’s RCA socket. Leaving a little slack in the cable and supporting it behind the cabinet reduces strain on the socket’s solder joint.
