Hello,
I also have to agree with daltonlanny about the JC-1's. I own a pair, and could not be happier! They synergize with my system really, really, well.
The Parasound HCA-3500 does at first sound more transparent, clearer, and livelier than the JC-1's, but over the long haul I could never live with them because they are slightly grainy and etched, and can become very fatiguing because of their high harmonic distortion.
I do feel that there is probably some room for improvement, especially in the mids and highs, cause nothing is perfect.
I however, do not feel that they are "closed in", "boring", or "lacking life" in the mids and highs at all.
In my system, they are all the things daltonlanny described above and more. They are very lively, extremely detailed, exciting, and sort of upfront in my system. Never dull!
If they are not fully warmed up or fully broken-in, they can sound lifeless, dull, and boring or closed down in the mids and highs.
I simply do not have this problem at all in my system with these amps. I luv 'em!
Angela