Have a newer (about 6 months old) tube amp. Last night I was noodling around and started hearing a ragged secondary tone coming from the amp. If I plucked the D string, 5th fret the proper tone would sound and also the ragged secondary tone. Only happened from a portion of the fret board. Its happened before with different strings/frets. and I believe different guitars. Later the amp started putting out a fairly loud steady tone of its own. Couldn't tell where it was coming from at first but I walked around and shut off all the electrical stuff I could and the tone was coming from the amp. Cycled the amp and all is well. This amp has made popping and snapping noises intermittently since I got it. It made one particularly loud snap/pop just after I got it and plugged it in for the first time. Don't think its from the guitar. This was my old standby SAS. Anyone care to speculate as to what the heck is going on? Thanks, Bob G. Also getting an intermittent buzzing. No floresent bulbs running. Will try the tube tapping discussed in earlier thread. No Ideas??