So I recently bought a Digitech Digiverb and when I first played it with a battery in, it was sounding fine until about 30 minutes later when the sound just cut out. I tried many things to fix it, but nothing really worked until I changed battery, from which it worked for about another hour. Now the thing is, when I tried to build up volume in my playing, it will just cut out and I'll have to re-plug the battery in for it to work again. I'm thinking it could be that it eats up battery power stupidly quickly, or that a 9v battery just doesn't have enough power to support the louder sounds, but I am not entirely sure.

As a power adapter costs around 20-25 pounds, I am fairly hesitant in buying one, and so I wanted to check if any of you think it could just be the battery or the pedal itself. I am prepared to buy an adapter, but only if that is the problem. So, any ideas? Thanks in advance.