When you were changing a disc? How close were you to the speakers when you noticed the sound? Is it a hiss or a buzz? Is it equal level in each channel?
If it's a hiss only heard an inch or two from the tweeter then I would agree with Elizabeth. If it's a buzz then you might start checking tubes (the MC402 is a tube amp, right?).
If it's a hiss only heard an inch or two from the tweeter then I would agree with Elizabeth. If it's a buzz then you might start checking tubes (the MC402 is a tube amp, right?).