@jbhiller If this problem continues, one of the more common reasons is failure of the bypass capacitor on the power switch. This can result in a loud pop at times, depending on the Voltage of the incoming AC line when you shut it off. So it can seem to come and go.
DC Offset Issue in Don Sachs Preamp
I have a nice Don Sachs preamp. It's making an incredibly loud popping sound on power off. Obviously, it's always good to power preamps first then amps and reverse the order for power down. But, I'm still concerned about potential damage to my loudspeakers.
Would this be do to a leaky coupling cap at the output stage? Or not enough uF/capacitance to take out all the DC?
I could email Don but I bought the amp used and I got the sense he may have retired.
Any insight is very welcome. Thank you.