intermittently, 1 speaker on the car would player a bit lower than the other. this occurs once in a long time

then recently it happened again, but now, sometimes 1 channel also kinda pulsates in volume as if someones rotating the knob up and down and up and down

alpine 9857 head unit, boston pro60 components, jbl gto 75.4 amp

i swapped some wires around to trace down source of problem. seems like its the amplifier itself, that its sending out weaker signals from 1 channel (vs the other). this isnt even when the amp is WARM... this si when i just get into the car

so im pretty sure the amp is f'ed and theres no fix. anyone ever get similar probs?

 

get two test speakers, any kind. run speakers wires to the speakers outside of the car. as soon as you here the volume change on one of the speakers, mark that cable as the subject channel. switch the cable from the bad channel to the speaker on the other channel. see if it stops or continues. make sure both speakers do not have the connections reversed. sound will come out of a speaker that has the polarity reverse, but it will sound distorted.