I'm using the high-level inputs of my amp - why does it get hot and shut off?

I'm using my factory stereo with the high-level inputs of your amplifier. Why does the amp heat up and sometimes turn off?

I'm using the factory radio in my car with the high-level inputs on one of your amps. Why will it turn off for a second or two and then come back on? Actually, the answer to this question is quite simple. Let's look at this like we look at amplifier power: The factory systems in some cars are high-power and are already amplified. We know that an amplifier will make a certain amount of power in watts. We also know that signal power coming out of any amplifier is A/C (not D/C), and will be measured in Volts. Most factory source units make between 3 to 13 Volts A/C on their speaker-level outputs (2 to 42 watts with 4-ohms resistance), not including the amplifier. A factory amplifier can make the signal voltage jump from 10 to 20 volts A/C (25 to 100 watts at 4-ohms)! You can verify this by playing a test tone through the system and measuring the output with a multi-meter.

Since we know that most high-end aftermarket head units make 4-volts A/C on their pre-amp outputs, you can immediately see that line-level outputs from any factory head unit or amplifier are much higher in voltage than most pre-amp RCA outputs. Because of the problem of trying to integrate aftermarket amps to factory head units, manufacturers introduced high-level inputs on their amps, and other manufacturers made high-to-low-level converters. Both act in the same way - to reduce signal voltage by providing higher resistance and lower sensitivity. Since our new amplifiers handle up to 4-volts of input on the RCA's, and up to 11 volts on the high-level inputs, we know that any signal greater than that will cause the amplifier to "clip". Adjusting the Gain controls all the way down to their least sensitive 4-volt setting will help, but will not solve the problem of too much signal input.

Unfortunately, the factory systems will "peak" at higher voltages then many of the converters can accept. When this happens, it passes the additional voltage right to the amplifiers, causing the amplifier to "clip" due to the increased signal voltage input. This clipping is what's causing the amplifier to heat up, and potentially shut down or turn off briefly.

How do you fix the problem? Using a high-quality converter will help. In some cases, you cannot use converters or the amplifier's high-level inputs due to the power levels coming from the factory system. The only way to make it work at that point is to switch head units to an aftermarket one with dedicated low-level RCA outputs.