Congrats on the new preamp. Since you now have $1800 burning a hole in your pocket I'd recommend upgrading your amp while you're at it. If you sell the Rotel you could pick up either of these, which would likely show similar types of improvements to those you experienced by replacing the Cambridge with the Rogue.
https://www.usaudiomart.com/details/649542736-clayton-audio-m70-monoblock-amplifiers/
https://www.audiogon.com/listings/lis9fehd-mccormack-dna-1-smc-gold-special-solid-state?refsource=hi...
https://www.usaudiomart.com/details/649542736-clayton-audio-m70-monoblock-amplifiers/
https://www.audiogon.com/listings/lis9fehd-mccormack-dna-1-smc-gold-special-solid-state?refsource=hi...