I have my old 1970's vintage V-4B power plug hooked into a power strip. I have flipped the power strip switch to the ON position, with the amp still in the off position and have heard audible sizzles and crackle going on for a few seconds (sound is coming from the head). This is the first that I have noticed this. The amp works fine and gets great sound and has never quit. I have just found it odd that I am getting this noise with the amp power still off. There is something going on in there when the power cord gets juice. Any cautions or suggestions?