I am running an EA Iamp600. I play a Zon Sonus 4, Yancey 4, and Benavente 6. All things being equal with settings...basses set flat, EQ set flat on head, I'm only adjusting the pre-amp gain and the amp output. The Benavente sounds weak and clean, but it never comes close to clipping the pre-amp of the head with the Pre-gain maxed and output set to noon. The Yancey sounds clean but can get dirty as I increase the pre-gain with output set to noon. The Zon sounds clean, but it easily gets dirty and starts to clip the heck out of pre when I increase the gain to around 11:00. Why does the Zon clip the pre-amp so easily?