Ok so a few weeks ago my amp started making popping noises so I decided to replace the tubes. Both sets of tubes were replaced with the recommended tubes stated in the manual. Upon firing up the amp and letting it warm up for 10 or so minutes I kicked the standby switch off and the amp made one pop and then no sound at all came out. I've checked the 2 known fuses that I know of and they are fine. Soooooooo what is going on??? Why am I not getting any sound?