Original radio modification

I may be getting a little ahead of myself as I have a crap load of work to do to get my project running much less listening to the radio but my mind and my ideas never stop lol. So I have an idea but im having trouble figuring out all the details I have my original solid state am radio I want to keep it stock appearing I dont want to cut a hole in my dash to install a pioneer so what i came up with is a simple and affordable Bluetooth converter it links to my phone and plugs into some speakers which im gonna hide away and plays without a radio. Here is my problem how do I power the speakers without hooking them into a stereo? Im open to ideas if anyone has a better idea.