Best practices when conducting a DAC comparison

@georgehifi   Is there a 'cheater' way to get close enough? : )

I can do so, if you and others believe it is critically important.

@rbstehno   I have a long history of audio bricks as doorstops. : )

It would have been nice to have. In the end it wasn't a deal breaker for me.

@georgehifi Is there a ’cheater’ way to get close enough? : )

No.
If you do it by ear, you could be as much as 3db out on level matching.
Cheers George

@david_ten 

As I mentioned in my 11-06-2017 1:17pm post, "I ensured the volume control on my amp never changed". So while I do not disagree with George, it could be a moot point and you may want to forgo the hassle of precise level matching. Why, because the difference among the DACs may (and likely should or will) be audible from a tonality, dimensionality, or other characteristic that can be readily detected irrespective of level matching. Personally I'd "worry" about precise level matching only when and if you're at the stage when all else is equal. 

"I ensured the volume control on my amp never changed"
  it could be a moot point and you may want to forgo the hassle of precise level matching.

All dacs have different analogue outputs levels even if it's by a 1/10th of a volt, how can anyone compare dacs sound, if the levels are not matched, even a minute increase in level will favour that dac in an A/B comparision.

Cheers George