[Edit – I was wrong. Please see the discussion below: Low volume / distortion with xlr microphone ]
Sure. Under fairly loud test conditions (94dB, 1kHz) the microphone @dylanious is using produces an output voltage of a millivolt or two, with an impedance of about 290 Ohms (see “Sensitivity” and “Output Impedance” specifications here: https://audixusa.com/docs_12/specs_pdf/OM6_v3.1_0719.pdf )
Most guitar amps are expecting an input voltage maybe 100 times bigger than that, but with a much higher impedance in the 100s of kiloOhm range. I’m making these number up, but they’re probably in the right ballpark. This is why, when plugged directly into the Duo, the microphone has such low volume.
If you put a transformer with, say, a 1:100 turns ratio in between the mic and the instrument-level input, you can step up the voltage from mic level so that it’s closer to what the Duo is expecting.
It turns out that a 1:100 transformer also raises the impedance of the signal by a factor of 10,000 (that is, 100 * 100). So this would take the 1.5mV, 290 Ohm signal and step it up to a 150mV, 2.9 megaOhm signal. This is just about in the right range for instrument level inputs like the ones on the Duo. You’re still better off using a good mic preamp like the ones on a mixer, but this will work in a pinch.
Does this make sense?