I think I understand you, but you’re mixing subjective impressions (that only you understand) with technical points about ‘power’ which others correctly point out is more than adequately provided by a DAC with a 4 volt output.I dont think most people who only recommends the rme are realizing the issue I have.
the RME ADi-2 sounds good with SCM7 and SCM19. But 40A is a different kind of beast!
I can not explain it but its like it needs double what RME can give. It needs a wider soundstage.
Its highly unlikely anyone here has compared as you’re going to, so rather than hope for validation here, it’s probably better to decide for yourself with your dealer’s support. By all means let us know what you find though. Bon chance!