Watch the Shuffle Up #1 online guitar lesson by Jeff McErlain from Solo Factory: Chicago Blues
On this tune, and quite a bit of Chicago blues, I am using the major pentatonic scale primarily to get that brighter sound. This sound is also prevalent in British blues players like Eric Clapton, Jimmy Page, and Peter Green. A generalization is that Texas blues is more of a minor pentatonic sound and Chicago is more of a major pentatonic sound. THIS IS A GENERALIZATION, but a nice rule of thumb is when describing this sound or when someone asks for a "Chicago blues thing" you know what they mean. When some one says they want a Texas blues sound I automatically think of SRV and tunes like "Texas Flood" or "Pride and Joy". When I think of the Chicago sound of soloing I think of BB KIng and major pentatonic.