I have a boss subwoofer amplifier which I recently discovered was causeing the distortion I have been hearing in my car. this amplifier consists of a PWM powersupply turning the 13.5v from my on car to a +45 -45 power supply. Then there are 8 mosfet transistors, 4 in parralel powering one phase of audio, then another 4 in parrelel powering the other phase of audio. I am reading on my DMM that the amp when put to the max I can get a 40 ish volt output which is plenty more than I need and to be expected. But when the amplifier is hooked to my 2 subwoofers at 2 ohms (which the amp is rated for) I can get an absolute max of only 14-ish volts and a lot of distortion. This sounds exactly like the power supply pukse width modulator is not working correctly. So I checked all of the power supply switching mosfets and they all work. so then I replaced the modulator chip itself expecting that to fix the problem and yet it did not. any ideas?