How to expand of line inputs?

I have a Placette single linestage pre. I always thought that would be enough for my stereo needs. Then came PC audio. Now I would like to use my cdp and SB3 without having to plug and unplug. Do people have a suggestion (short of replacing my pre) for being able to connect both the cdp and SB to the pre? I'm thinking there must be some kind of splitter (perhaps with a toggle switch) but I'm not sure about whether it would degrade the sound quality.