Rockford fosgate would rate their amps to 2 ohm but could run all day at 1 ohm. Many brands do not rate to max. Would whyni think home audio brands would be different when they over charge for gear all the time Or lie about the quality of parts they use.
OK, time for a quick lesson- those Rockford-Fosgate amplifiers were wired to one or more car batteries and their power supplies weren't tightly regulated, so when peak power was needed, the batteries provided more current than a wall outlet could provide. Cranking batteries are rated at more than 800CCA- directly applied power is calculated by using P=IE, where 800 x 12V = 9600W and at 120VAC, the circuit needs to deliver 80 Amperes to achieve that power and neither is going to be 100% eficient. Not gonna happen. Class AB car amp efficiency can be assumed to be about 50%, on a good day.
Also, the only way those amplifiers could run all day at 1 Ohm is if the voltage doesn't drop, cool air was blown on the heat sinks, the amp wasn't mounted directly on a carpeted panel and wasn't mounted upside-down. I have seen Rockford-Fosgate amplifiers that stopped working because they became so hot that component solder joints melted and parts fell out. It wasn't Rockford's fault, the amps were installed incorrectly.
The little transformers in audio equipment could never deliver the current needed for this level of power. Direct Current design and circuits are very different from Alternating Current. Power supplies that plug into a wall outlet deliver higher voltage to the rest of the amplifier than a car audio amplifier needs in order to develop high power- again, P=IE, so if the battery voltage is only 12VDC, power isn't going to be high, so back in the dark ages of the 1980s, MOS-Fets became popular because the amp manufacturers started providing the high voltage needed for the output transistor power supply rails by incorporating an oscillator to create AC voltage which is far easier to increase using a transformer while this can't be done with DC.
