Inside the house I have had some trouble with all my detectors do to EMI of one kind or another, outside it all goes away.
In 3 years and several hundreds of hours hunting with my Compadre, with the sensitivity turned up to the max internally so it is very "hot", I have only come across one site where I had to turn up my disc knob high to stop noise that was higher than I really wanted to do.
Even near or under power lines, in direct site of towers, up a mountain withing direct line of site of every radio, tv station and cell tower for miles around and all other situations I have come across there has never been one site where it became so noisy it was unusable.
Most times a slight turn on the knob from my usual low area of all metal or iron gets rid of any noise in the very rare times it does happen, not enough to really matter and it never enough to affect my hunting or the things I can find.
Don't worry, take it out and start hunting with no worries.