Sweep picking has been talked about so much here. I think someone on this forum did put i video of them sweeping picking once.
http://www.guitartricks.com/forum/showthread.php?t=9114&highlight=sweep+picking
Thats one thread from a while back where i explain the basics of sweep picking.
I think if you just go to "home" on this site and search for "sweep picking" you will find some very usefull tutorials too !
By virtue of their electrical properties, tubes generate a special waveform when they're saturated, which is why tube engineering has tremendous tonal advantages over solid state or DSP solutions, particularly for crunch and lead sounds. Tubes enter the saturation zone gradually or softly, which lends tube-driven tone its trademark yet totally unique character.