i owned a krc-3 for ~8 years & was sad to let it go recently. It's a very good pre-amp. I found it to be quite nuetral, letting source components sound, well, the way they sound ... good or bad.
i left mine on all the time, except for when i knew i would not be listening to it for extended periods of time. i shut my whole system down. as u know, the krc-3 doesn't come with a power on/off button so i think krell designed it to be left on all the time. i found it sounded its best, like the krell amplifier i also owned, after they'd been "cooking" for some time, at least 24 hrs. it runs hot so leave lots of room around it.
the krc-3 sounded its best when connected with balanced cables to the amplifier. i used MITs.
good luck.
i left mine on all the time, except for when i knew i would not be listening to it for extended periods of time. i shut my whole system down. as u know, the krc-3 doesn't come with a power on/off button so i think krell designed it to be left on all the time. i found it sounded its best, like the krell amplifier i also owned, after they'd been "cooking" for some time, at least 24 hrs. it runs hot so leave lots of room around it.
the krc-3 sounded its best when connected with balanced cables to the amplifier. i used MITs.
good luck.