if you have a multimeter, you should check the output voltages of your MicroBrute, just to be sure the converter is properly calibrated, and that you are using the good notes to get 1V and 4V.
You need to check:
for 1V: set MicroBrute to octave -2, hit left C.
for 4V: set MicroBrute on octave 0, hit center C.
the measurement should be accurate by a few mV(depending on your multimeter precision)