On one receiver, I have a 12V trigger. Is that 12V linked to ’power on/off’ of the receiver? How many mA can those 12V triggers typically produce (to directly control a relay)?
Receiver 12V trigger output usually can provide up to 50-100mA. If you want to directly control a relay, my suggestion is utilize solid state relay since its input is optocouplered and only require a few mA to activate. To control 1500W power amplifier, choose a SSR can handle 40A or higher.
Will now try if the big phat 1500W power amp can be controlled (I assume it has a ’softstart’ to not smoke that power strip right a way.
If your ’fancy’ power strip ’controlled’ outlets can’t handle the load of 1500W amplifier for long run, I suggest diy a box with 120V power relay/contactor controlled outlet plug into the power strip.