Understanding the LT3045 based SLS-HPULN module
The SLS-HPULN power supply consists of "two rails in series", each can deliver up to 2.5 ampere from 5x LT3045 (parallel) regulators, resulting in an Ultrahigh PSRR of 76dB@1MHz for EACH rail. This is pretty good, so good that it doesn't make sense to power it with another regulator, an audio grade transformer is definitely a good decision to deliver power here. Nevertheless some customers have other concepts of recification or buffering power, in this case a rectifier / diode would waste power resulting in unnecessary heat. In this case one is good to decide for "DC" as an input option.
Read also our blog "How to maximize PSRR" to understand more, how the SLS-HPULN power supply helps to reach this goal.