EL DAC II+ uses ES9018K2M, as THD+N rating is identical to ES9038Q2M, and the 9018K2M has no output stage. This means we have full control over designing and tuning the analog stage in the 9018K2M. Also, 9018 runs cooler and is more affordable, so there is little incentive to use 9038Q2M except for simpler marketing! People assume bigger numbers are better--ESS is quite arbitrary with their naming assignments.