We have an Angelcare monitor as well & found HUUUUGE interference with it, but I unplugged my phone charger one night & there's no more buzzing at all!

I haven't used the pads even though there is a history of SIDs in my side of the family. I think it's worth the money, but we couldn't use it -FYI if you use a Snugglebed the sensors don't feel the movement through the 2 mattresses.