Krell S300i vs Hegel H100 vs Parasound

I'd strongly recommend finalizing your speaker choice first so you can optimize synergies in the critical amp/speaker pairing. I'd also greatly favor running a good integrated rather than pairing a good amp with your Rotel. I also had an older Rotel pre/pro (RSP 980 I think) and while not horrible it cannot provide the tonality, imaging, or overall refinement that the preamp section of a good integrated will provide. Don't make the mistake of underestimating the critical importance of the preamp in the audio chain. Hope this helps and best of luck.

Agree with Paraneer you made the right choice and congrats. Given your preferences I'd recommend the Hegel over the Krell. If you read the reviews the Krell excels in power and control and from the mids on down, but since you don't listen all that loudly I'm not sure the power and control would be all that important to you. Of more concern is the treble that has been described as thin and brittle and upper mids as nasal and more rosin than tone on strings. For those reasons the Krell doesn't seem like a good fit for you, but the Hegel on the other hand would seem to be an excellent fit with its more refined or less pronounced upper mids/treble relative to the Krell. Hard to see you being disappointed with the Hegel.

If you can stretch your budget and would consider buying used, some other brands worth considering would be Ayre, Pass Labs, and maybe Musical Fidelity. Or perhaps even going higher up the Hegel line. Given you're running $7500 speakers I'd think they would reward you the higher up you go if you can swing it. Best of luck in whatever you choose.

How much higher is hard to say since it's so subjective. I just think you've got excellent speakers that would justify and greatly benefit from higher quality amplification. And if they're rated at 4 Ohms it's a good bet they drop below that in at least one point along the frequency curve. One example of a higher level integrated would be a Pass Labs INT150 that's for sale here listed at $3700. It puts out 150W and doubles into 4 Ohms that I think your Dyns would appreciate, and it operates in pure Class A up to 10W that would probably be where you'd do most of your listening. I think this could be a great fit both for your speakers and your listening preferences, and it should be much more than an incremental improvement over an H100 or H80. There are several reviews from Stereophile, Positive Feedback, 6 moons, etc. that would be worth reading. I think it's more on par with the quality of your speakers as well. It's like buying a sports car -- you could put cheaper tires on it and it will still run, but it's capable of providing much better performance with better tires.

The Halo is a nice recommendation, but the treble is likely to be a little hotter than the Pass. Not sure if it would be too much or not -- that's entirely your call, but the risk of you finding the treble irritating is probably higher with the Parasound.

I think you're greatly limiting your choices by requiring an onboard DAC. And the way technology is changing I'd recommend buying a standalone DAC, which would also give you more choices there as well. For better or worse.

Using an external DAC or not doesn't really have anything to do with speaker EQ, room correction, etc. If you don't have a well-designed and treated dedicated audio room I think speaker/room correction is one of if not the most significant and cost-effective improvement (depending on what product you use) one can make to a system. The demonstrations I've heard were pretty much jaw dropping in terms of the improvements, and just goes to reinforce how big an influence the oft-neglected room plays on the sound we hear. There are several products out there, but for effectiveness, cost, and overall ease of use I like this well-reviewed unit:

http://www.dspeaker.com/en/products/20-dual-core.shtml