Bananas Vs Spades???

Yes, this is the main drawback of using bare copper, it oxidises fairly rapidly. We can therefore assume that the signal will degrade over time also. A gold plated end sleeve will prevent this, but how to get a good connection with these? I do feel that manufacturers can do far better in this area?

Ps

Spades hands down. Better surface area contact, can be torqued down extremely tight and less vibrations. They sound more powerful on same cable used.

Dave_b is correct. However, just remember Frank Schroder's famous comment "the next step after really tight is totally loose...

Yep, I believe I did tighten some spades once that became loose....uh, broken:O(