The mAMP you could call our 'third generation' series amp and is quite a different beast than the SX series amps. It utilizes different circuitry, a redesigned input stage, different topology, the latest ICE module technology and is housed in a completely redesigned chassis. The result is an elegant looking, compact and very efficient amp that delivers a more liquid, organic sound with slightly wider bandwidth compared with the SX amps. However, if you need more than 250 watts of power in 8Ω (doubling at 4Ω), than the SX-1000 with 500 watts of power in 8Ω (doubling at 4Ω) is definitely the way to go.