Can I use 2 amps with same wire?

Yes. You can splice the tip of the remote wire, just before you reach an amp, and tap 2 wires, one from each amp. Ive seen some people put a jumper wire from the remote terminal of one amp to the remote terminal of the 2nd amp. It works.

Do I need a relay for 2 amps?

You dont need a relay if you just run a switched 12v wire from the fuse panel. You can just tie all the amps to that wire. The circuit will be beyond strong enough to handle whatever you throw at it and it will be fused at the panel. Just use like a 2A and youll be fine.

How do you connect amps together?

2:326:07HOW TO Strap Amps - Linking Two Strappable Mono Amps!!! - YouTubeYouTube

How many times can you split RCA?

RCA Splitter Cables (Hook-Up Two Channels with One RCA Jack) As you can understand from the picture the complete function of RCA splitter cable. You can get 2 from 1. With this cable, you can connect with 2 amplifiers even if your system has 1 RCA jack.