Korg Monotribe: How to silence oscillator when filtering external audio

One of the downsides with the monotribe is that you can´t switch off the oscillator when you are processing external audio. There is a way to get around this problem though: the trick is to modulate the oscillator with the LFO so its constantly above the audible frequency range (and also above the highest cutoff frequency of the filter), this way you can´t hear the oscillator anymore and you can filter any external source with the monotribe!