I note that PA-1 has like main output the Speaker Out.
To connect de device to an amplify that has only RCA input can I use the 3.5mm headphone output ?
In the manual the headphone output is declared only for temporany or setup use.
If not, how can I solve the issue ?
Thank in advance
As you are saying, the 3.5mm port is for installation and maintenance purposes only, not for the connection of other devices, so we strongly suggest to avoid using this to connect to a RCA input.
You would need an amplifier or a device able to get in between the PA1 and your amplifier, something able to get the audio from the Speaker Out (4W / 8 Ohm) and to get it to your RCA input.