The way I figure it, the sounds you get are exactly what you'd get if you mic'd the amp itself, including any noise that's present. That's why it's so great... instead of just modeling the amps sound, it accurately reproduces an actual amplifier. To lessen noise or feedback, try doing what you would do with an actual amp... use less wattage, mic the amp from further away, turn down the treble or presence... last but not least, use a VST EQ to dial out the frequencies that are bothering you.