Now, I´m designing alarm tone generator with microcontroller. Microcontroller generate square signal output at 1450Hz. This output have a voltge divider and low pass filter for volume control and attenuation at frequencies outside the audio band. I don't be sure to use a rigth opamp type. In diagram is OPA134 but could be OPA1604 for impedance coupling. Then audio is converted in balanced audio by DRV135 and so transmitt a large distance to amplifier equipment. Opamp use a dual supply voltage +/-15V from DC-DC converter isolated and microcontroller use a regulator voltage +5V, all type of voltages have a unique source from 24VDC but differences references.
My questions ,Could I have problem in amplification of audio signal from microcontroller with reference different of opamp since opamp use reference from isolated converter? and Voltage divider P1 is rigth for volume control where this signal converted to balanced will be amplified by amplifier equipment with input mic?
Thank in you in advace for your asisstance.