Last night, during rehearsal, I tried a second hand Ampeg SVP Pro with an Ampeg Power Amp (can't remember the model but 400W@4ohm) on a Genz Benz 1x15" cabinet. I liked the sound but was little confused by "lack" of power : gain in middle position, 2/3d in volum, input -15Db because of my active Bartoilini pickups (perhaps I should have let it at 0db ?). I still had a hard time being heard sometimes. Any advice, experience on that kind of rig ? What cabinet should go with it ?