Is it possible to locate the output of the preamp an an audio interface to connect it to a different A/D converter. Or are there more complex ground looping and impedance issues here?

 

Is it possible to locate the output of the preamp an an audio interface to connect it to a different A/D converter. Or are there more complex ground looping and impedance issues here?

Do you think that all "audio interface" and "A/D converter" follow the same design?

 

gain is more likely an issue to check. A standalone mic pre-amp might have between 40 to 60 db gain and will bring the output up to line level,
A standalone AD converter would I suppose (having never had one) expect the same level. The specs of the unit will tll you.
The signal level at the point between the two in a integrated design could be quite different and you would need to make measurements.
The final output stage of a modern pre-amp circuit is probably an op amp and I wouldn't have thought there will any impedance matching issues. If there are, they will be easily seen when making the connection.
Ground loops are always a possibility when interconnecting audio equipment and the only thing you can do is try it. Then track done the cause if there is one.

blocco beat me to it ! But I didn't answer the first question. Of course it's possible to locate the point where they meet. Question is can you ?