Audio Systems: fault finding, channel amplifier, back doors

Question
hey again,
            i havefound out that all the speakers that are connected to my 4 channel amplifier (which are a pair of splits up the front and a pair of 6 inches at the back doors) are all cutting in and cutting back out. they dont completely cut in an dout but just drop off the volume a bit every now and then. when i turn the volume right down i can hear a fuzzy sound coming from the speakers. when the speakers cut out when the volume is on they go a bit fuzzy as well then when it kicks back in it goes back to being perfect. i have tightened all connections at the amp but it still does it. what do u think is wrong with it?

Answer
sounds like dirty controls to me. i'd get a spray can of 'de-ox-id' and open amps enough to be able to access the backside of the controls, find small opening and using spray extension tube, spray into control and work cotrol shaft vigorously for a few seconds. reassemble everything, hopefully this will help. if there was another problem, amp would just quit and not come back....good uck...