Thanks for the ideas. Unfortunately the "popping" effect is rather elusive and would require more vigillance than I think is possible. The crackling sound that is like when a connection is loose is a bit more regular and seems to occur at about and hour to an hour and 1/2 into a dvd. I have bought replcement KT-88's so I'll see if replacing them solves all issues or if not back to the experiments.
My Amp makes strange popping sounds.
Recently my Cary SLI-80 tube integrated has been making strange popping sounds. CD playback has been fine and until recently so has LP playback. The amp and CDP are plugged into a PS audio Ultimate Outlet. I recently hooked up for HT and the DVD player causes scratchy electrical sounds periodically (maybe twice) during a movie. Now I just heard a popping sound while listening to a record. Any ideas? The preamp tubes are new and the 6SN7's are recently replacements. Could it be the KT-88 output tubes (this is the older Cary SLI-80)? The amp just came back from repairs so I imagine the internals are okay. Basically I don't know how to diagnose this problem and wonder if these symptoms are based on the tubes or should I be looking at power source and grounding etc. Any ideas would be appreciated. Thanks