for fork sake !!

Read the AMP application notes about "gas tight connections".
We found in our final test system of appliances, that the communications through crimped on spade terminals under barrier strip screws were 15 year reliable, even on dry circuits.
The pressure of the screw holds out the oxygen. The pressure of the AMP crimp terminal barrel melds stranded wire into a mass that excludes the oxygen. Similar looking terminals from ali,ebay,Radio Shack don't have enough metal to exclude the oxygen.
I find the spade lugs under binder terminals on my home amp speaker connections, never need cleaning. By contrast internal punch blocks in the commercial amps, have channels drop in and out occasionally. Punch blocks were invented by Bell for 48 v telephone signals. Those were not dry circuits; the voltage would burn off the oxide. Delta relay catalog said dry circuits were those under 50 v and under 50 ma. The signals that drop in & out in my old pa amps are under 2 v, thus they are dry circuits.
 
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