Most definitly.

I left the amp in my car on over a weekend.
Battery was dead as door nail.

Install a remote switch (just don't forget to turn it off!) or wire to stereo/ignition.

I have the same problem with my Optima stereo battery. I am on my third one. Time to install an on/off switch.

if your amp is wired up correctly, it will only power up when the stereo is on as well. That is what the remote wire is for.

If by AMP you mean stereo amplifier, there should be a wire for remote on/off that you should hook up to the stereo or a switch. Sorry not from the US so my english isn't that good....

Check the orange wire on the back of your alternators. Its your charging wire.