I can’t return the sub because I bought it from the original owner who also bought and didn’t use it. Also don’t have the box.
i am looking into conversion adapters while also list it for sale and trade.
rec out is not an option as the sub will stay at the same volume regardless of the amps volume setting.
as far as google, I’ve always thought of forums like this as places to seek help and share with others interested in similar pursuits.