Hi, I just put in a new set Winged C 6l6gc's in my '66 fender bf bandmaster. I biased it and cleaned the tube sockets. When I lightly tap(or wiggle it) on one of the 6l6 tubes I hear a gentle pop/crack. Cleaned the tube socket again it was less but the pop/crackle was still there when I tap on the tube. Not always, but sometimes it pops/cracks. So it is a little bit better. Should I repeat cleaning a couple of times or is it something with the socket? Maybe very dirty? Didn't checked solder joints jet. I cleaned it with contact cleaner with lubricant (was all I had around). Want to order a good Deoxit without lubricant soon. The Winged C's sounds great btw.