Hi all.
I am in the process of designing a new 8 channel DAC/active XO/preamp for my active 4-way system and I want to add a 12V trigger out to remotely start the amplifiers, four Fosi Audio ZA3.
The DAC will have a 5V SMPS to power the standby/activeXO/MCU circuit (Raspberry Pi based) and a linear PSU that provides 5V for the DAC digital circuit and +12V/-12V for the output stage (a simple opamp based I/V circuit).
My concern here is how to provide 12V to the trigger out circuit, in special how to avoid introducing noise and how to avoid ground loops. My previous experiences with Fosi's trigger in was terrible. The port doesn't seem to be isolated from the main circuit so, if you connect a noisy device, the noise goes directly to the audio.
In my current design, I used the 12V line from the linear PSU (the same that powers the I/V stage) through optocouplers to ensure the complete isolation between the MCU circuit and te 12V circuit. My concern here is to introduce noise in the I/V stage, coming back from Fosi's trigger circuit.
Another option that I see would be to add a new tiny 12V PSU just for this circuit (a linear or a filtered SMPS as Fosi's trigger in will introduce noise into the system).
For the experienced electronic circuit designers here, would you please recommend the best approach? Maybe adding filter caps in the trigger circuit?
I am in the process of designing a new 8 channel DAC/active XO/preamp for my active 4-way system and I want to add a 12V trigger out to remotely start the amplifiers, four Fosi Audio ZA3.
The DAC will have a 5V SMPS to power the standby/activeXO/MCU circuit (Raspberry Pi based) and a linear PSU that provides 5V for the DAC digital circuit and +12V/-12V for the output stage (a simple opamp based I/V circuit).
My concern here is how to provide 12V to the trigger out circuit, in special how to avoid introducing noise and how to avoid ground loops. My previous experiences with Fosi's trigger in was terrible. The port doesn't seem to be isolated from the main circuit so, if you connect a noisy device, the noise goes directly to the audio.
In my current design, I used the 12V line from the linear PSU (the same that powers the I/V stage) through optocouplers to ensure the complete isolation between the MCU circuit and te 12V circuit. My concern here is to introduce noise in the I/V stage, coming back from Fosi's trigger circuit.
Another option that I see would be to add a new tiny 12V PSU just for this circuit (a linear or a filtered SMPS as Fosi's trigger in will introduce noise into the system).
For the experienced electronic circuit designers here, would you please recommend the best approach? Maybe adding filter caps in the trigger circuit?
Use the 5V supply and MCU to drive an optocoupler and its secondary transistor maybe used by the downstream amp at any suitable voltage, as opposed to 12V only.