Welcome to AC Sharpei!!!
Assuming your preamp and amp both have balanced (XLR) connections then you should have no problem doing what you propose. Just turn power off to the amp first to avoid thumping your speakers. It is pretty difficult to harm a CIA amp, they are well protected. If you have a high gain model amp CIA (intended for a passive preamp) then you may find that your volume control has a small range of motion before it gets too loud.
Hope to see you posting on AC in the future.
Rich