Hi everyone, this is my first post and I was hoping someone can help with a problem I'm having with my 11 Rack. So I bought it used a few months ago and everything was working fine but now when I play, it will work like normal for 10-30 minutes when it will suddenly make a loud static/popping sound. When I quickly turn the volume off to save my ears there is no sound at all when I turn the volume back up except a subtle pop every time the volume nob is moved. I've tried changing cables with the same result. I am using the XLR out into a Tech 21 power amp. If anyone has had a similar issue or has any suggestions it would be much appreciated. Thanks.