Another reminder again to make sure you press the manual button before you tweak any settings to your liking. The amp will sometimes weird out if you happen to be in channel mode (1 or 2) and you go turning dials on the amp. It should let you modifiy the presets ok...but watch for any weird sounds or dramatic volume changes. It won't hurt the amp at all...it just isn't the best way to tweak sounds as you won't get accurate settings. Try to get into the habit of hitting the manual button anytime you want to change stuff on your presets or your channels is all.