Behringer ultracoustic acx guitar amplifiers behringer acx450 the 45w behringer ultracoustic acx450 guitar amplifier features two channels and is the ideal amp for a one person show with an acoustic guitar and a mic for vocals if youre just getting started as a guitarist this is a great way to play along with your favourite tunes or if youre playing an extended set you can use the cd in section to provide music during breaks the acx450 features numerous audio solutions at the tou