That demo didn’t really sound like shellac to me at all: it sounded like a distorted Les Paul. Just my ears. I didn’t come here to debate those tones though, but to say that I get a good shellac vibe running the Black Spiral through a bridge single coil pickup with the tone knob maxed on the guitar. The Black gives that very cutting high end, that I hear in shellac guitars. The Black allows your picking attack to be defined and doesn’t muffle up your clean tone like other fuzzes do. To me, those are the characteristics: Treble presence, strong guitar attack and likely lower gain dialed up than what our ears perceive on those recordings.