Replace Switch to power AV Receiver
You were going in the correct direction. Try this circuit, it should work like what you need. It will accept 1-12V at input. 

This is the most basic configuration. It should work in most cases. If you don't want to load the control signal, you can increase the base resistor to 2.2k, 4.7k, 10k or 22k. But to use larger resistor than this, you may also need to consider how much current you need at the output.







simulate this circuit &ndash; Schematic created using CircuitLab