Ah yes, the old audio taper pot. I use them for tone pots on my guitars. CTS and Bourns are some of my favs in that realm.
But I can appreciate the design and benefits of actual stepped ones.
I'm drawing a brain fart in the connection aspect, getting old. Assuming a completed amp, I cut the + connection at the RCA input. Each end of the resistive strip, lug 1 and lug 3, go across the + and - lugs of my RCA input, the wiper goes to the + input of the amp.