It is important to make sure that you use gold plated contacts with gold plated pins, and tin plated contacts with tin plated pins. When gold and tin are mixed by putting gold plated contact against a tin plated pin or vice-versa, the direct contact between the two dissimilar metals causes a chemical reaction over time. It can take months or even years to happen, but tin oxide will build up on the gold and eventually, cause the electrical connection between the socket and connector to become unreliable. While you may get away with mixing gold and tin in the short run - eventually you will start getting errors resulting from the oxide buildup.