Audiopipe APCL1500D1 went into protect mode today (been running it daily for about 2 years on 2 12D4 Type R's at 1 ohm). Used a DMM to check voltages, 14.0 V at the +/- at the battery, 6.2 V at the +/- terminals at the amp, 1.2 ohm resistance at the +/- speaker inputs on the amp, and less than 0.05 ohm variance at the sub +/- terminals. Ground is clean, remote turn on voltage is proper, fuses look good. I'm thinking a budget beater amp can only go so far and the amp itself is toasted.