So the other day I bought a ts-9 tubescreamer from guitar center. Everything seems to work fine except that the turn on/off pedal itself doesnt seem very responsive. I sometimes have to hold it down for a few seconds because if I just quickly press down it turns off as soon as I release. Its like it needs some time to engage. Could this be because im using the battery and not an ac adaptor, or is this something that I should take back for a replacement?