The original Evolution bridge model did exactly what Steve Vai wanted it to do: kick butt and produce serious scream. Then he wanted something a little more complex--the same basic tone with increased headroom and dynamics. so that the sound kills on 10 and cleans up when the volume is rolled down. With a little less power than the original Evolutions, Evo 2 balances perfectly with the Evolutions neck model and performs equally well with high gain and vintage amps.