This amp is the best external sub amp I’ve ever owned. I’ve also owned several SA-200 and SAM-200 from RBH. They are all tremendously powerful, but the sa-400 is something special. It pushes so much current, yet stays cool. At times, I’ve driven two 1010-sen/reference subs with a single amp without issue. It’s the quality of the low end that’s remarkable. Immensely deep and produces waves that roll through your body. I have used them with multiple RBH subs models from 8” to big 12”. I’m currently testing out a pair of JBL subs (LE14H-1 woofers) both showing a combined load of 3 ohms. The amps always cool, and it brings out the very best sound from them. I’ve swapped several other amps, both pro and not. The RBH sa beats them easily. I own three SA-400 right now. I expect they will last my lifetime.

They don’t make them anymore.