Not sure what you're trying to do.
1.5volt AC is 2.1volt peak and 0.9volt DC after the bridge rectifier when smoothed.
The normal way is to rectify/smooth AC first, and then drop that (12*1.4) -1.2 = 15.6volt with a divider to what you need.
Things ofcourse only work that way when the AC source is 'floating'.
Leo..