Don’t use an RCA-Y. You could use a small, inexpensive mixer. Regardless, this is not recommended if you intend to have both TV’s operating simultaneously.

Note that when AMP is used to drive surround speakers, Line-In and SUB out are disabled.

I dont think you understand what I want. The tv will not be operating simultaneously. I want to share the sub with the 2 zones due to their close proximity and how large the sub is. The 1502 crown when bridged only uses Ch 1 input. I want both amps to input sub out to drive the amp. A autosensing selector from bobwire is $279. But would switch seamlessly between the 2 sonos amp sub outs. And if I were to listen to music on both they would be grouped so the zone 1 sub out is the main only needing 1 input. Just can't believe an auto switch for 2 rca inputs is $300.

A Y is exactly what I want. but can't get an answer about the sub out on a sonos amp is already auto sensing. It detects a sub when plugged in.

RCA outputs are normally low impedance, inputs are high impedance.

(Not your situation) Hooking two inputs together is usually not an issue as the output has the available power to drive two, or more inputs.

Hooking two outputs together often results in distorted sound as one output absorbs the signal from the other output, leaving the input seeing a distorted signal.

Using an inexpensive two input pre-amp (active, not passive) should avoid the impedance mismatch problem and also assist in level matching if needed.

Do not use an RCA-Y. Here is a simple mixer. It’s the operator’s responsibility to avoid playing audio from both. I’m not aware of any off the shelf, simple, foolproof automated scheme to do this. The operator can simply mute the audio from one source when necessary.

Here is a slightly different approach.

Thank you this may be a better solution i will look into it. My only worry would be input level i know some mixers are mic level only. Headed to read the specs thanks again.