I’ve been using my RME ADI 2 Pro as a preamp direct to power amp (tube, soild state, and class D) for a few years, as well as a headphone amp, without issue.This should never have been bought up in the first place, the REM ADI 2 has 100ohm output impedance, with enough voltage to drive ANY amp into clipping, balanced and SE. Shows how things snowball without any reason to.
Cheers George