Hi all I have a problem with a Beolab 1, it emits a 'thump' sound when the signal is removed, or when the volume is reduced. This is the speaker as i have changed leads, signal source and sswapped speakers. I have included an attachment that demostrates the sound emitted. My thoughts are a cap has gone low ESR internally, but before i pull the amp board and start investigating i wonder if anyone else has experience or suggestions with this? Many thanks Michael