An electrical connection system for providing an electrical signal to a detonator of a perforating gun is provided. The system includes a tandem sub operatively coupled to a gun housing and having a sub body having a bore defined therethrough, a bulkhead assembly having a bulkhead electrical connector securable within the bore, and a printed circuit board assembly. The PCB assembly includes a cartridge having a connection bore adapted to receive the bulkhead electrical connector and define a sliding connection between the cartridge and the bulkhead assembly, and an addressable switch located within the cartridge body and in electrical communication with the bulkhead electrical connector. The detonator is located within the cartridge body and is in electrical communication with the addressable switch. The bore, the bulkhead electrical connector, the cartridge and the detonator are concentrically disposed relative to one another and extend along a common axis.