I recently purchased an RA180 along with the RS130 and RD160. I had heard that the subwoofer output doesn’t work for anyone since its volume doesn’t change, but was hoping they fixed it with a firmware update. Well, it seems it is a useless output and really shouldn’t have been included on the back panel.
I purchased an SVS Speaker Level to Subwoofer Adapter, in hopes that it would solve my problem. It in fact does not, as it cannot be wired up in the conventional way. I contacted SVS and spent some time with them working through the problem. It seems to be that the device needs to be wired up in a specific way to work without crackling noise coming from the speakers with what they call a differential amplifier (I’m not clear on that terminology yet, as they say this is rare, but I think it just means a fully balanced amp which is not rare at all).
I have done this and it works! Subwoofer levels now match the volume of the amp. (Shouldn’t be this hard…)
The solution is to connect the positive terminals to the RA180 and the adapter (normal way), then connect the negative terminals of the adapter to the RA180 chassis ground screw under the power inlet, and NOT to the RA180 negative speaker terminals.