Dedicated PC as in? Would I not be able to install the Plex media server in my laptop and cast content stored in my laptop (say MP3s) to a chromecast dongle attached to a HDMI port in my av receiver?
Harsha
Yes, for your use case of streaming audio from laptop, Plex seems good. I will give it a try too, just for fun

By dedicated PC I meant, you will always have to have the laptop, which can be inconvenient at times. If your audio content is in cloud, then you can use any basic android device to stream to chromecast. It is just about ease of use.