Hartke LX8500 800-watt Bass Head The LX8500 is a compact 800 watt amplifier designed for the big gig. Lean and remarkably robust, the LX8500 brings the thump, growl and bite you expect from your favorite amplifier without the back-breaking setup. Weighing in at just 8.5 pounds, this amplifier features a responsive 12AX7 tube-powered preamp that adds plenty of warmth and bassy richness, backed up by 800-watts of real, continuous power.