To enhance something means to intensify—exceed what we might find in a natural state. Which raises an interesting question. Is it actually better or merely different?
Let us be clear. Enhancement is qualitatively different than what we generally look for in equipment: moving closer to purity. Lower noise, better linearity, are all moves toward purity that do not claim to enhance. Instead, they do less harm.
Changing a digital audio cable to a lower noise version would qualify as a move towards greater purity. Its bettered performance is a result of inflicting less damage.
A tube buffer would qualify as an enhancement since it is additive. (Despite your possible opinion that it is merely colored).
One big question in this same vein concerns preamplifiers. Do they enhance or purify?
We know that inserting a certain quality of preamplifier between the DAC and amplifier improves performance. But why? Is it an enhancement or is it doing less harm?
Over the years I have come to the conclusion it is doing less harm—isolating the digital side of things from the power amplifier’s analog purity.
But, I remain open to further learning on the subject.
If you want to dig a bit deeper, I’ve recorded my thoughts on video. Watch Do preamps enhance sound?