My amp. a 10 year old Pioneer has outputs for connecting speakers for surround sound. I'm looking at Brookstones cordless speakers. The manual says to use the RCA pin plug output on the amp to connect to the input on their cordless transmitter. In the absence of that I can use a 3.5 mm connector. My amp has neither, just traditional speaker wire connections to r and l surround speakers. The Brookstone manual says not to hook the "dual RCA cable to speaker terminals on your audio source or you may cause damage." Are they talking about the RCA plug itself? Why can't I use a connection with bare wire on one end -my amp-and the RCA plug to the imput on the Brookstone transmitter for the r & l speaker connections?