Hi - I have an original sprout that was formerly connected to a subwoofer that had RCA connections, and everything worked perfectly.
I had to buy a new subwoofer though, and am using Kef’s HTB2 sub. The issue is that this sub only accepts LFE cable (hope I’m saying that properly) and I cannot for the life if me figure out if I can connect the Sprout to my new subwoofer.
Yes, connect the Sprout 3.5mm analog output with and adapter to a RCA plug and you will get sound. The details and pictures are in the Sprout owner’s manual.
The problem is the Sprout is sending a full range signal, not just limiting it to below 120 Hz. You may get some distortion. Your KEF sub does not have a Low pass filter built in. It is designed to be used with a receiver that has a subwoofer output filtered by a crossover.