Swap your tubes, only one at a time, left channel for right channel to see if it is indeed a tube problem and to identify which one if so. (Power-down the amp while removing and installing tubes.) At whichever step the problem moves to the other channel, then you've found your bad tube. If nothing changes, then tubes aren't your trouble. Report back after testing to let us know.
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