Watch the Jazzy Clean online guitar lesson by Jeff McErlain from Guitar Effects Survival Guide
The classic jazz guitar tone is usually a hollow body or semi hollow body guitar like a Gibson L5 or a Gibson 335. The big hollow body guitars are often referred to as a jazz box due to their size. Since most of us don't have a cool jazz box we can kind of fake the sound to a certain extent buy using the neck pickup and rolling back our treble, this will warm up the sound and get us in that ball park. The use of a boost pedal will fatten up the tone and help emulate the sound of a jazz box, not exact of course, but in the ball park.