Strangely enough it is the interfaces between equipment that often determines more about sound quality than the units themselves—something disconcerting to those among us working hard to make the perfect sources and controllers.
And I don't just mean cables.
Take for example single ended vs. balanced. Running single ended between equipment is always an uphill battle, while XLR just cruises along. Or, input vs. output impedance. In professional equipment they're always matched, hi-fi equipment almost never. Amplifier to speaker, source to preamp, phono cartridge to phono input.
We've such an eclectic group of boxes available to insert into our systems that it's no wonder mixing and matching has such wildly varying results.
Standards would be nice, though I don't see them coming.
For now, it's skill and ears determining the optimum interface.