I have an old jukebox with limited speaker output (switchable 2W, 4W, 8W, 20W). I would like to connect it to a 100W bluetooth amplifier so I can connect some external speakers to give more volume (and also play music from my phone). Can I connect the old speaker output (presumably at 2W) directly into the RCA auxillary input of the amplifier? There is no 'line out' as far as I can tell. If not, is there a work-around?