I take the 12V feed from the same empeg/headunit/speakerphone feed, not the amp.

I can certainly hear at least one relay in the ck3000 when mute engages or disengages, but it's also cutting off 8 speaker wires and inserting 4 of it's own at the same time, so the relay sound might take care of all of them, or just the speaker level signals. I'll use the diode.

Again, thanks.

-brendan