Problem with electrical feedback on valve phono stage?
I have recently purchased my first valve phono stage (second hand) which sounds absolutely great. However, at switch off the amp makes a thump – if I am not mistaken only on the left channel - there is some sort of electrical discharge that perhaps shouldn’t be there? The thump can be heard irrelevant of whether the volume has been turned up or down.
What is this problem most likely to be and is this an easy problem to rectify?
Thanks for any hints or relevant info. in advance. Much appreciated.