You're not comparing two seperate sub amps are you? Even if they are the same model the gain won't be in the exact spot on both
x2
and the h/u has to do at what level the amps will start to clip, different h/u send different amount on voltage to the amps so if you have an amp that does not clip with one h/u it dont meant it wont clip when you install it to a different h/u
He changed out the sub amps, not the head units
just letting him know that an amp can clip even if it wasnt clipping on an earlier install, if i remember correctly he said he bought the amp from someone else used plus he is testing 2 amps and trying set them the same, even if they are same brand same model it will clip and different gain settings