I have used low voltage (120Vac - 6.3Vac) power step down transformers as audio output transformers in small amplifiers. Testing them has taught me that they make pretty good wide BW transformers. They will respond from below 50 Hz to beyond 40 KHz and are pretty linear. As long as you do not saturate the core of the transformer then the output should show a pretty good rendition of the waveshape of the 120V source. And the isolation provided, alone, makes it worth trying.