I have a pair of these I'm going to pull from some old RCA monitor amplifiers, and convert into a passive stereo box just to send through for some color. I just am not quite sure how to read the diagram.
Am I correct in thinking that the in is 3, and the out should be 10, for the 600ohm?... but where is the ground?
Also, what effect would 150 have instead? I read somewhere some people wire switches for different tone using each ohm.
Also, where is the ground wired too?
So, not actually summing?
That's a 10 Watt part. You are not going to get "color" with line-level signals.
"Grounding" is not needed in your application as long as signal goes through.
Get a bag of clip-leads and some plugs, try it.