So...I recently pulled the trigger on a new Matchless Spitfire Combo. It sounds just great! I've had it for less than a week, and when I plugged my Tele in today, and rolled my volume up, I get a low level crackling noise...almost like a campfire in the distance. I swapped cables, guitars, and even put all new fresh tubes in, and it's still there! I run the amp through a Furman power conditioner as well! Just for kicks, I set up my trusty 1968 Fender Princeton, plugged into that, and SAME CRACKLE from that one now! Same thing with my Tweed Harvard. I will say that the crackle goes away in the hum-cancelling middle position. There is ZERO crackle from any amp with the guitar volume rolled down. Of course, I'm grounding the strings with my hand, and the tiny bit of 60 cycle hum with the single coils is totally acceptable. I tried different outlets in different parts of the house...same thing. So...I've ruled out the guitar, cable, tubes, amps... What else could it be? Bad AC in the house? I turned the Air Conditioning off to see if that made a difference...but it did not! Any thoughts? Thanks!