Re: What Spade Size for M30 Speaker Terminals?
I have measured a gold binding post of the type we've used for about 5 years. I measured the central pillar as 8.3mm diameter and I suggest that about 8.5mm would be a nice snug fit. 9.0mm would be a little loose but would still make good connection. You could probably bend inwards the tips of an over-size spade to improve its contact area.
In my opinion, it makes no real difference whether you connect your spades to the upper or lower terminal pair if the biwire links remain fitted.
Alan A. Shaw
Harbeth Audio UK