Hey. Tried and failed to resurrect old thread: http://audiokarma.org/forums/index....assive-pop-when-low-filter-is-flipped.588093/ Reposted here: Thank you, ahead of time! problem description almost matches an issue I have with my otherwise very lovely and beloved 828. Periodic, random loud crack/pop. Volume up or down. Sitting at idle, no load on it. Other than that, heh, she is fine. Same possible source? Q? "Coupling caps" described above are on which board? Schematics of Tuner and AF Unit show cap numbers that go that high. Thanks again! Jimmy UPDATE: Other Post appeared under DIY. Sorry about the double post. L.