There are some details missing from your question. Are your amps 600 watts each? If so, then you need to plug them straight into the wall unless you have PS AUDIO P15, at a minimum, or a P20 for optimal power availability to the amps. If your amps are 600 watts each, at full load, they may consume 600 watts or more each from your outlet and any PS Audio device. This would mean that you need at least 1500 watt power supply but you will be running that device at almost 80-90% load. Not too safe for long term use. That is why the PS AUDIO P20 is better if you want power regeneration. Keeping the sources separate on the PS Audio is fine as long as you do not run into ground loops which could create hum. If the PS AUDIO is plugged in the same outlet as the amps, provided you might be using an audio power strip to the other outlet plug in the same outlet, you should use a 20 amp circuit to provide maximum availability of power for all your devices.
If you don’t listen to full power, it may be safe to plug all into a 15 amp circuit, depending on how your amps turn on. This is related to power surge and draw at start up/turn on of the amps. With all connected and if you turn on amps and the power draw exceeds the watts/amps of the circuit, your circuit breaker will trip. That is one way to test if your circuit can handle all your devices in the same plug.
You should invest in a power/watt meter which will give you real time power usage of a device plugged into an outlet. This would be helpful to determine how much actual and real world power your amps are using. You can test one amp and then multiply by two to get the total estimated average power draw. You can measure each amp separately to get a more granular average of power draw from the amps.
Power Usage Monitor