The Sonos Amp is designed to be connected directly to speakers, as it has a built-in amplifier. It is not designed to be connected to a receiver/amplifier. If you want to connect a Sonos device to your receiver, you want to get a Sonos Port.

From Sonos:

Can Amp connect to a multi-channel AV receiver?

No. Amp only has speaker outputs. It does not have any analog or digital output for connecting to an AVR.

If instead you mean a Sonos Connect Gen 2, then the answer is yes. On the other hand a Sonos Connect:Amp, no.