I swear by the Spark Mini as the most transparent boost I have ever tried when you have an amp with killer core tone - not looking to tighten low end or roll of highs or anything. I picked up one of these full size Sparks and was blown away - it can be as transparent as the single knob Mini if that's what you want - but has endless subtle tone-shaping capabilities if the amp needs more or less of anything. $60 is a bargain. GLWS