The MAC 500 and 600 can be modified to accept 5-pin XLR connectors. One option is to use Neutrik D-series 5-pin XLR PCB-mount connectors. On MAC 600s without locking connectors, these can be substituted directly. On MAC 500s, and MAC 600s with locking XLR connectors, the panel cutout must be enlarged approximately 2 mm in diameter and new fixing holes must be drilled into the connectors (not the panel).