Was thinking you might benefit from being able to use Krell's current mode and cast system if you get a Krell preamp. Since you're looking for a single box, here's an Evolution 222 available now...
https://www.usaudiomart.com/details/649506480-krell-evolution-222-stereo-preamplifier/ but there are some Evo 202s available too. Then again, there's also this special situation on an $18k Krell Illusion preamp...
https://www.audiogon.com/listings/lis9df6c-krell-illusion-solid-state
Also, here's a nice Vitus pre that retailed for over $14k in your price range.
https://www.audiogon.com/listings/lis9d723-vitus-audio-rd-100-reference-series-dac-preamplifier-in-g...
Best of luck!
https://www.usaudiomart.com/details/649506480-krell-evolution-222-stereo-preamplifier/ but there are some Evo 202s available too. Then again, there's also this special situation on an $18k Krell Illusion preamp...
https://www.audiogon.com/listings/lis9df6c-krell-illusion-solid-state
Also, here's a nice Vitus pre that retailed for over $14k in your price range.
https://www.audiogon.com/listings/lis9d723-vitus-audio-rd-100-reference-series-dac-preamplifier-in-g...
Best of luck!