gvl

Is pre-out just hardwired to the RCA output or there’s more to it, eg it’s taken before tone controls?

Me too!

In case of no filter the HF droop that begins around 6khz is most certainly audible on 44.1khz sampling.

Is distortion in high frequencies of any consequence? I can’t hear above 14khz or so and cannot be bothered by harmonics of >7khz...

You apply a set of specific EQ corrections for each headphones, they will then sound better across all genres/songs. That said, you can...

Yes, as long as RCAs and XLRs are independently buffered.

To use EQ properly you’ll need to learn how to take acoustic measurements with a microphone and derive necessary corrections from them...

Is that number already adjusted for tariffs?

How common is this? Basically one needs to have multiple devices with volume control upstream, I suspect not very common. As you say an...

Sounds like you’re a corner case.

Do tell.

Is there a common use case that multiple inputs in a mono power amp serve?

Valid points, but DACs have to be stacked by performance somehow, hence the SINAD-based ranking/chart.

If you were impressed by (mostly placebo) effects of a new filter, maybe try better cans, you’ll be blown away.

A lot of industry still thinks we don't exist.