Originally Posted by K3cT
It's probably something like upgrading from a good DAC to a great one.
That's kind of what I'm afraid of... It's REALLY hard to tell those apart. For example, the Benchmark DAC1 HDR is a good DAC, but not perceived as a "great" DAC by many. The DAC in the Marantz SA-7S1 is supposed to be better, and in my experience it is indeed better, but only very slightly so. After much A/B testing, I found very few cases where I can tell for sure that it sounds a tiny bit better. However, these tiny differences are way below the threshold of something that you would notice unless you were specifically looking for it during A/B testing. For all practical purposes, these DACs sound the same. I can say the same thing about the DAC1 vs. the Bel Canto DAC 2.5. The DAC 2.5 sounds very slightly better in some cases, but the difference is so minute that it's way below the threshold of what I would obsess about (even though I tend to be a perfectionist).
Similarly, I haven't been bothered by any differences between the 323S and the KGSS so far. In this case, I haven't done side-by-side testing, but after listening to the KGSS for 4 years, I don't notice any deficiencies now that I listen to the same familiar music on the 323S. The KGSS may be technically superior (in terms of amp design), but I don't hear this superiority reflected in the actual sound it produces with the SR-007.
On the other hand, the deficiencies of the unmodded 727 and the 007t are noticeable to me, and these are above the threshold of what I would consider to be significant.
I guess I need to listen to the BHSE to figure out if the advantage it provides over the KGSS is like the advantage of the SA-7S1 over the DAC1 or the KGSS over the 323S (which are insignificant to me), or like the advantage of the KGSS over the unmodded 727 or 007t which I find significant-enough to care about.