Reply to Will my old speakers work?

I have 2 old Yamaha speakers that i found in my house, they are top of the line (for they're time; late 90s early 2000s). But they only have the input for regular speaker wire not RCA cables. I have 2 RCA to speaker wire cables but was wondering if i just hook that up to my S2 (which should be coming in the mail today) adnd use the level knob to control the volume would it work, or do i need to use a amp.