Signal cable makes speaker cables with smaller spade connectors for older amps. I use their cables on my Scott 299. Should be the same size for your Mac.
Spade connection size for McIntosh MC2155 Amp
I recently was given a McIntosh MC2155 as a family hand me down. I would like to incorporate this into a 2nd system. I'll be pairing it with a set of XR16. I would like to order some new cables but am not sure what size spades are needed for the amp side connections. Any recommendations on decent cable brands that accommodate the vintage sized spade connections?