\n| NL8<\/td>\n | 4<\/td>\n | 4<\/td>\n | 8<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Read together with the cable range, this is the whole decision. A four-pole connector with a four-conductor cable feeds two circuits; a four-pole connector with a two-conductor cable feeds one circuit and leaves two contacts unused.<\/p>\n Pin numbering: what 1+, 1−, 2+ and 2− mean<\/h2>\nBuyers rarely ask for a connector by pin set. They ask for it by pin marking \u2014 “pin 1+”, “the 2+ contact”, “a 4-pole with 1− on the left”. The same contact is written two ways in the trade: 1+<\/strong> on the connector moulding, and often +1<\/strong> in a written specification or an RFQ. Both mean the first pin set, and the numbering is what makes a multi-pole connector unambiguous once the drawing leaves your desk.<\/p>\n\n\n\n| Connector<\/th>\n | Pole markings on the body<\/th>\n | Circuit 1<\/th>\n | Circuit 2<\/th>\n | Circuit 3<\/th>\n | Circuit 4<\/th>\n<\/tr>\n<\/thead>\n | \n\n| NL2 (2-pole)<\/td>\n | 1+, 1−<\/td>\n | 1+ \/ 1−<\/td>\n | \u2014<\/td>\n | \u2014<\/td>\n | \u2014<\/td>\n<\/tr>\n | \n| NL4 (4-pole)<\/td>\n | 1+, 1−, 2+, 2−<\/td>\n | 1+ \/ 1−<\/td>\n | 2+ \/ 2−<\/td>\n | \u2014<\/td>\n | \u2014<\/td>\n<\/tr>\n | \n| NL8 (8-pole)<\/td>\n | 1+ to 4+, 1− to 4−<\/td>\n | 1+ \/ 1−<\/td>\n | 2+ \/ 2−<\/td>\n | 3+ \/ 3−<\/td>\n | 4+ \/ 4−<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Two rules follow from the markings. A pin number is not a circuit: 1+ and 1− together are one circuit, so a four-pole connector carries two speaker circuits and not four. And polarity is decided by which conductor sits on which marking, not by the colour of the wire \u2014 if 1+ lands on one conductor at the amplifier end and on the other conductor at the cabinet end, the cabinet receives an inverted signal. The symptom is not silence: it is a thin, low-output result when two cabinets stand side by side, and it is very hard to trace once the rack is closed. Mark both plugs before soldering.<\/p>\n Bi-amp: which pair goes where<\/h3>\nA four-pole connector hands you two pairs \u2014 1+\/1− and 2+\/2− \u2014 and that is exactly what a bi-amped cabinet needs. Which pair feeds the low-frequency section is set by the cabinet and the amplifier, not by the connector: brands differ, and a cabinet that uses 1+\/1− for its full-range or LF input is not the same as one that assigns the pairs the other way round. Take the assignment from the label on the cabinet or the amplifier manual, write it on the specification, and terminate both ends to match.<\/p>\n Compatibility, correctly understood<\/h2>\nThe formats share a common locking principle and the smaller formats fit the larger sockets by design, so an NL2 plug can be used in an NL4 socket. What is not shared is the circuit count: fitting a connector does not add circuits.<\/p>\n When replacing a connector, match the pin set count to the existing cable, not to the socket it happens to fit.<\/p>\n Why the connector is not just a plug<\/h2>\nProfessional twist lock connectors are built around three practical requirements: a locking mechanism that will not release under vibration, a cable retention system that grips the jacket rather than the conductors, and a housing that survives being stepped on. A chuck or clamp retention system holds the cable by its outer jacket, which is what protects the terminations when the cable is pulled.<\/p>\n What to write on the specification<\/h2>\nState four things and the ambiguity disappears:<\/p>\n \n\n\n| Inspection point<\/th>\n | What to write<\/th>\n<\/tr>\n<\/thead>\n | \n\nConnector format<\/strong><\/td>\n| NL2, NL4 or NL8 \u2014 or simply the pole count<\/td>\n<\/tr>\n | \nCable conductors<\/strong><\/td>\n| How many, and the mm\u00b2 of each<\/td>\n<\/tr>\n | \nChannels required<\/strong><\/td>\n| How many speaker circuits the run has to carry<\/td>\n<\/tr>\n | \nGender<\/strong><\/td>\nPlug or socket, and the count of each<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\nReplacing a connector on an existing cable<\/h2>\nWhen a connector is being replaced rather than a new cable being built, the cable in hand sets the limit. Count its conductors first, then choose the format that matches:<\/p>\n \n- two conductors \u2014 NL2, or NL4 with two contacts unused<\/li>\n
- four conductors \u2014 NL4<\/li>\n
- eight conductors \u2014 NL8<\/li>\n<\/ul>\n
Choosing a larger connector than the cable supports does not add circuits. It leaves contacts unconnected, which is a common source of confusion when the system is later expanded.<\/p>\n Retention is not a detail<\/h2>\nA twist lock connector holds in two places: the lock that stops it releasing, and the retention system that grips the cable itself. A chuck or clamp that grips the outer jacket protects the terminations from strain. A retention system that grips the conductors instead puts the load on the smallest part of the assembly \u2014 and for cable that is coiled, dragged and re-terminated, that difference decides how long the assembly lasts.<\/p>\n | | | | | | |