Hey everyone. I'm new to the forums, and I was going to ask for some help regarding my new "Line 6 Spider IV 120w". I just went to my local guitar center today, and purchased my new amp. They were out of stock so I just got the floor model. So already people have tried it out, and I was told it has only been there for about a week. So nothing was really wrong with it. When I try to play it sounds great. But when I switch it to the metal sound I just want to make it louder, but whenever I try to adjust the master volume it just makes a really loud screeching sound. Is there any way that I can adjust the volume without it having to make a screeching sound? Or it just normal? Thanks.