[salamander]

On US and Canadian MC452 amps, the correct way to insert banana plugs on the output terminals is the way you originally had them, inserted vertically into the hole on top of the lock nut (page 9 of manual). The banana plugs fit a little more than halfway into the output terminal. When you loosen the lock nut, the lower hole exposed below the McIntosh cylinder is for attaching bare wire, or a spade around the post the hole goes through. Although it may be a bit disconcerting to see some of the banana plug exposed when plugged into the top of the output terminal, quality plugs fit very snugly. I have tried both banana plugs and spades on my MC452 and both sounded great. I really could not distinguish a difference in sound quality and ultimately chose to use the banana plugs mainly for ease of connecting/disconnecting.