How to link two cores with TRS connector?

[Aliasing]

I must connect the signal (the level,3.3V) with the analog input(MIC LINE/GUITAR IN) of MOTU4pre by 1/4" balanced TRS. In other words, one channel (signal and ground, two cores) is linked with TRS connector(three big core, Positive(+or hot), Negative(-or cold) and Ground).

Could you tell me the idea's feasibility? How to do in detail?

Thank you.

[lfm]

TRS Ring and ground to ground/shield.

Signal 3.3V to tip.

Line input would be the one I tried first, if that has enough attentuation.

[BertKoor]