Roadster Channel 1 Issue

[knotts]

I noticed the past few weeks that my roadster makes a crackling sound only on CH1. If I switch to any other channels it goes away. It happens after it's been on for a little while. Any thoughts on the problem would be greatly appreciated.

 

[knotts]

Just to throw this out there because it's still happening. I recently changed all of my preamp tubes from V2 to V6 and the crackling continues. Is it likely that it's the V1 preamp tube? Strange that it's only on Channel 1. When I switch to any other channel it stops immediately.