Amp or speaker first, upgrade

I will also add my vote to keep the Krell. It’s an excellent piece of equipment if you know what to expect from it. The Krell equipment use bipolar circuits (as opposed to FET based circuits). They are higher bandwidth and higher resolution circuits so make sure you have a very smooth/refined source (i.e. DAC) as the Krell can be very revealing of any flaws or digital like character coming from the DAC (there’s nothing laid back about the Krell). That being said, the Class A preamp circuits are excellent. If you want laid back, look into something like the McIntosh stuff, which is very full-bodied, but very laid back (very forgiving of a bad source). To me, the McIntosh stuff just has no excitement or life, but that’s my personal preference - as many love McIntosh.

I have never been a fan of Definitive Technology speakers. They tend to be very bright in the high frequencies and the bipolar speaker design can cause the highs to be very messy and bright/harsh. There are certainly much better speaker choices to select from.

The Aerial 10T’s are a very nice older speaker. I know somebody who has them and they are very nice with the Krell KAV-280p preamp he uses. They are looser in the high frequencies (not as controlled) and they do not have as much midrange body as something like a B&W speaker, but they are very nice. I have not heard the newer 20t that uses a ribbon tweeter.