vox amplug

I just bought the Vox amPlug2 for the bass. I had a very early version of the same device for guitar. I was surprised at how nice it sounded for both guitar and bass; although the advert was for guitar only. I bought it when my 2 year old son (now 8) was receiving chemo and radiation...

So I just got an amplug 2 bass for some low volume jamming when away from home and there's a fair bit of white noise coming out of it. Worse on high gain settings and comes through whether the amplug is plugged into the bass or not. For those that have one -- is this typical or is my unit...