I tried the Wall Mart 9v battery. It worked for a little while and in fact I recorded a short (30 min) set with it in the field with a 2GB card. However, on another date when I tried a 4GB card and let it run, it seized after about 10 minutes. End of 9v use, but fortunately no permanent damage to the deck. I'm back with a new set of rechargeable AAs.