Adding treble on my bass amp also adds a hum to it; Anyway to cancel it out?

Whenever I add some high on my equalizer, it adds a hum or fuzz. And then when I add distortion with high or treble, it amplifies it..A LOT. Is there a problem with my amp itself, or is a bass never supposed to have that much treble..? (Around 6/12 on the band) Thanks.