You all may laugh, but my go-to amps for this application are Hartke 12' Kickbacks (KB12). The latest one is the best so far. It has a '500 watt peak 250 RMS' amp that can be removed easily to drive a 15' cab if you need to use it That way. A little pricey, and now made by Samson I think, but can"t be beat for what it is: a hybrid aluminum-coned 12' speaker driver driven by a 500/250 watt amp with tone controls. Just right for grab and go mono, and works a charm for more lows with my QSC K8.2s or my Spacestation SS3. I just got an open box KB12 from Sam Ash for $380. New, they"re closer to $500. Built rock solid. Some fan noise.
And it has an XLR output, +9dB, so no direct box needed.