One wonders if Jimi Hendrix had the blues students of today in mind when he said, "Blues is easy to play, but hard to feel." However, when the self-invented wild child of blues, Debbie Davies, hits the stage, it all makes sense! From my first "plug-n-play" of Davies in my studio at a small stick in New England, Davies' manipulation and passion of the strings ignited the station populace. The Duchess of Blues was loose and out of control. Every lick had fever pitch. It was the blu …