Hoping I can tap the braintrust here for a little help diagnosing an SVT-CL issue. (First, yes, I have some tube amp repair experience and know how to keep myself safe poking around inside one of these beasts.) This issue: when the amp is turned on, off standby and being played for a few minutes, I started to notice a crackle coming through the speaker. Sounds like static. It happens intermittently if the amp is sitting idle, and I realized I could make it happen by tapping any of the three driver/PI tubes on the back of the amp (crackles as I tap the tube). My first thought was to roll some new tubes and rule that out, which I did. Didn’t help. Re-tensioned the tube sockets and cleaned with dioxit. Didn’t help. So, next step was to pull everything out of the cabinet, fire it up on the workbench, and tap around a bit with a chopstick. Here are a few things I took note of: - the crackle actually happens when tapping anywhere on the primary (larger, bottom) circuit board. - the crackle is quieter (but still there) if the volume on my bass is off, regardless of the level of the Gain/Master on the amp. - the crackle gets louder as the bass is turned up, and is loudest when I’m actually playing something. Any ideas would be greatly appreciated. What does the behavior above indicate? Is it likely to be a bad component on the board itself, or in the connection of this board to other sections of the amp? Thanks!