Does the quality of the spades matter

OZ - yes and no.

Copper over time will oxidize and cupric oxides can tend to be semiconductive, thereby forming semiconductive films on areas that have been exposed.

Silver oxides (tarnish) are conductive and therefore do not exhibit the same potential for affecting the signal that the cupric oxides might pose.

Having said that, any good binding-post interfacing with a spade will render the junction gas-tight, therefore no distinct oxidation will occur. There may be other potential problems, such as metals migrating (i.e. a pure copper spade on a gold plated binding post is a place to watch for migration or "leeching").

Well, of course copper spades will have to be periodically cleaned and the connections retightened, that goes without saying and I doubt that a really gas tight junction can be made down to a molecular level and yes, metal migration is indeed a problem. Bad connections are audible. I can clearly hear improvement, especially in the highs, whenever the spirit comes over me and I clean them all. When sibilants become sssibilants, that is genereally the signal for me to gnash my teeth and rend my cloths first and then get going.

Heymable, thanks for the post and welcome to the world of Audiogon forums. I hope you will become a regular poster -- I didn't know silver tarnish was conductive. That's why we have these "discussions" here -- so we can all learn. I'm with Detlof that connections don't tend to stay air tight over time and an occassional cleaning is required, but I get your point and appreciate the response. All else equal (i.e., personal preferences to copper vs. silver), a silver spade might be the better choice.

I don't mean to put you on the spot, but could you explain a bit more about metal migration? What exactly happens? Do copper and silver behave the same way with gold. If the leeching occurs between the speaker binding post gold plating and the speaker binding post base metal, do you think the additional leeching of the speaker binding post gold plating to the spade might also affect conductivity? Thanks.