Yeah, you're right, when differences are obvious a DBT isn't stressful, but who cares about differences that are so obvious?
When differences are
present, a DBT isn't stressful. It's a fun game, for those with the occasional inclination to nerdiness (see, e.g., your humble narrator) When they are
absent, it often is.
I don't need a DBT for the obvious, but long-term satisfaction is often determined by subtleties.
Long term satisfaction with audio electronics usually has little to do with how they "sound," and everything to do with other factors.
And different does not mean better.
Nobody, of course, claimed otherwise.
What was claimed is that absent difference in a given variable, there is no basis to form preference along that variable.
***The 707 weighed a ton. It also wouldn't load a CD fresh out of a factory-sealed box. Very annoying.
Now there's a great example of a non-sonic reason to prefer (or in this case, to not prefer) an electronic part!
A couple of years later I tested it against a Audio Research DAC-1-20 and with matched levels I remember I picked out the AR as "better" some majority of a small number of times. I was convinced enough to buy the DAC-1-20, which was expensive for me at the time.
Wasn't that the DAC that couldn't drive a paper bag? Like .7V maximum output?
Low maximum output levels is a likely culprit there.