Quantum units can be applied to almost any hi-fi or AV system with results that far outweigh their cost. Their impact is neither subtle nor hard to hear (or see), but in the case of a hi-fi system, there is a simple approach that will make appreciating the Quantum effect even easier:
The music will seem louder, clearer and more natural, with greater presence and a more coherent sense of space. Over time you’ll also notice that you are hearing the system less and the performers more, something which is particularly apparent on intimate or live performances, voice and piano (think Holly Cole). Once you’ve heard the Quantum affect, you’ll always hear it, whatever the music, and whilst you might hear it first or most readily on something small scale and acoustic, the results on larger scale music can be even more important.