Hello everyone, anyone can recommend or advice me where or what kind of switches/amp I may need. Here is what I want to do. Take the audio source from the computer, RCA or optical (SB X-Fi HD) or motherboard built-in sound. Amplifies and output to a pair of small speaker (Polk Audio Monitor 30), and can also output to a headphone (Sennheiser PC360). On the device Ibe able to switch between the 2 and a volume control.