2 amplifiers, 1 pair of speakers

Any ideas on the best way to achieve this? My friend has a sony multi-channel amp for HT and a Cary SLI-80 for 2 channel listening. The speaker wires are currently plugged into the Cary. For movies, the Sony runs the surrounds and uses the pre-amp out to the Cary for the main speakers. The sony is off for 2 channel.

He would like to preserve the tubes for 2 channel only but needs a separate amplifier A/B type switch. Online searches have lots of speaker switches but we can't find any quality amplifier switches. One that accepts the spade terminations of quality speaker cables not the spring-loaded type for lamp cord.

Any ideas?

Thanks