I don't buy the solder argument, unless it is a poor solder connection. I have no proof save my word, but many years ago I helped make up a batch of RCA interconnects using a variety of solders and we (store I worked for) ran a series of DBTs over several weeks inviting friends and customers to try. Nobody could reliably tell which solder was best. I think it more likely the differences heard, and with the same cable in and out, are due to wiping action of the contacts. RCAs are cheap and easy to use, but in terms of providing a reliable, consistent connection they suck (can I say that?) Since most of us do not often change connections, a more positive screw-on connector would be much better. However, it would be more expensive, and of course subject to the nut with the lug wrench who decides if tight is good, tighter must be better, and spins the jacks in the components...