Hi there, I was hoping someone could help me identify a problem that has developed with my amp. I purchased a Marshall Astoria Custom 4 weeks ago and it was great at first. But yesterday When I first turned it on a noticed the hum was a lot louder than before and then it made a couple of popping sounds. now when I play certain notes I'm getting a terrible buzzing sound. I've tried several different leads and guitars to ensure the issue is with the amp. the hum and popping sounds happen even when no guitar is plugged in. Unfortunately I don't really have any experience dealing with amp issues. I've attached a couple of youtube vids for examples. Any help would be greatly appreciated. I have messaged marshall and they just told me to return it to the retailer for an exchange or refund but the retailer no longer has the amp in stock so I don't know if they can do an exchange and I don't really want a refund because I loved how the amp sounded before today.