I've been suing a non-speedball 1.1 crack for a few months now. When I first put it together, there is no hum, after a while, it develops a low humming noise which sometimes would go away after I knock on the wood enclosure pretty hard (I would hear a blip buzz then hummin stops). But that method doesn't work anymore, no matter how I knock on the wood, the humming continues at the same low level. A few details about the hum:
- The humming starts right away after the unit is powered up, and stops when the unit powers down, regardless of the music playing or not
- The humming sounds in the 100-200hz region, it's moderately loud, and stays the same loudness from low to max volume.
- The humming doesn't interfere the music, even when playing very loud music, the hum stays there almost like a separate instrument, other the hum, there is no significant change in the sound signature for the rest of the music
- Other than the hum, there is no crack or popping sound whatsoever
- My two red leds on the power tube is lit as usual
I thought there might be something loose, but I can't visually see anything that's loose, or touching
