Like i said in the last post i made i have never compared the 2 amps. The 1 thing i do know is that the z1 will heat up and fry before a 500.1 and is crap for daily. Diffrent setups yeld diffrent results maybe the z1 works better at a higher load then a 500.1. Just keep the 500.1 at .7 to 1ohm after rise and it will make good power.