I am using an AMPEG 4-PRO head. The cabinets I'm using (Basson) state to use 2 pin Sockets set at +1/-1 and MUST use a 2 pin cable speaker cable. Is the NEUTRIK Speakon NL2FC correct to use? I was told at a Music store I can use the NL4FC cause they were out of the NL2 but I see that the NL4 has 4 pins. I'm sure they are wrong. Is my assumption correct?