I'd been using my old GK400RB to power my Eden Navigator preamp through Eden 410XLT cabinet, since I had it lying around doing nothing, but I'm looking to upgrade the power amp now with a little more power/headroom. The GK400RB is only 200w @4ohm, I believe). Any advice/suggestions? I don't need mega wattage, just something within the 400w @ 4ohm/600w @ 8ohm area within a reasonable price.