Guitar/music question...
I've picked up a couple cheap Fender 15w practice amps that have RCA inputs for a CD player (or really MP3, phone, anything).
I got them so guests could jam with if they were so inclined.
They are likely the kind that comes in the $150 starter set with a guitar, bag, pics, etc.
They sound pretty good, and the most I've paid is $25.
I've not used the RCA input and I don't know how you control the mix.