I have a DM 4800 with 2 Tdif extension cards. Neither card seems to work at high sample rates (88.2/96) but they do work at normal sample rates (44.1/48). When set to high sample rates, the cards only pass loud white noise and a soft distorted audio signal. I tried different clocking scenarios without success. Do these cards not work at high sample rates or are my cards or my board defective?