I realise we are 7 pages into things. However, back to the beginning... What you are asking is easily done using an ESP32 or an ESP8266. I have done it with the latter ESP8266. This is a screen shot of my phone.Hello,
i have "audiophile" hifi system, even components are old the rpp is around 8000 euro.
The amp has manual power on/off switch / same for DAC and these are two components that i want to control via smart home.
For that purpose i want to create custom module that will be installed between 230V power socket and SUPRA MD06-EU MKIII mains.
The intent is to use Omron relay https://eu.mouser.com/new/omron-electronics/Omron-Relays to control Phase/Neutral/Ground (3 separate circuits) or only Phase (?)
The relays will be somehow controlled by some esp32 module (smart home).
The end2end scenario is that
- amp switch is power on permanently (musical fidelity nu vista m3)
- DAC switch is power on permanently (burson audio)
- custom made module will control relays and Power on/off whole system via esp32 automation
Is that doable or does it make a sense?
Thanks

With some code adjustment they could auto turn on in a sequence or as seen here they can be turned On/Off manually in any sequence. This is done over my LAN (Local Area Network. There are other wireless solutions as for example wireless relay cards like this one. I have not reviewed all the post so if this was covered my apologies.
Ron