Hi, I played my bass earlier and my amp was fine but I've just had a quick play on my bass and my amp is making a really strange noise in the background. It's a kind of gurgly white noise, and it gets louder the lower the notes I'm playing, it happens at all volumes and is persistent through whatever I'm playing. I have a Carlsbro 150W Stingray 1x15 combo. Please help. Any more info you need just ask. Sorry it's not a very technical question but I'm retarded when it comes to amps.