I stick with mainly old school Zed amps,and a couple others within that ERA that were rated at 11.6-12.9 v,that were not regulated,and that were under rated even then,so at our now 13.6v-14+v, those amps see more power,and deliver.Not only as that, but the TDH seems to be some much cleaner,as well as having a higher DB level,of 100+...Cheater Amps:awesome: Its Funny to see a 66 watt amp bridged @2ohms beating the garbage out of a 1000rms sub woofer @50% and the size of less than a sheet of paper.