Why not go modern? Bluetooth, whether you mound them and wire to 12v or just a small, portable variety, really work well for me.
Those little ones sound really good, and I can move it close to me, turn it down, and not bother my neighbors when I am listening to Tony Bennett.( seems they always want Pearl Jam)
Denny, Rosie and Josie the Beagle
2016 Allegro 36 LA
2016 Mazda 3