Probably, if you use batteries, its direct current while if you use the adaptor, its alternating current. Plus, batteries do strange things when they start to die.
it is true, the batteries do make alot of hum, and when they start to die they massacre you tone
R.I.P brother dime

Reppin for the new york death metal scene
what makes a man?balls and weiner my friends, balls and weiner
I used batteries in my Boss wah pedal, and they lasted a few hours (they were new).
Batteries suck.
Been away, am back
It is better to use an AC Adaptor because batteries will only last a few hours in your pedals, and even when you haven't turned on the pedal, if it is linked in a pedal chain, I have heard it still uses up the battery. For the price of an AC Adaptor, after a month or so of buying good quality batteries, you'll have spent the same amount that an adapter costs, and it saves you the hassle of changing battery.

The 1 Spot AC Adapter. It's brilliant, and the combo pack only costs 35 dollars at Guitar Center. I'm currently using it to power every pedal I own. It's a fraction of the price of one of those power bricks, and (according to the packaging) is more effective.

What I did was disconnect the batteries (but still left them inside the pedals) and hooked up the cables to each pedal. Then I plugged the AC adapters from the 1Spot into each pedal, and left the 1 spot unplugged. This way, all I ever have to do is plug in the 1Spot, turn on the amp, and plug the end of my effects chain into my guitar and I'm ready to go. No power being sucked from the batteries OR my wall outlet when not in use.