sorry to crash your forum but i have the same problem with my system.
Had a sub and amp in previously with no probs.
tried with 6x9s and it began to cut out!
I was going to purchase a new headunit anyway so i got the Alpine cda 9853r at a good price BUT the problem still persisted. I tried another amplifier but no luck still.
checked all the wires to make sure that there was good connection.
but now that one of the posts indicates is that it could be related to a weak power supply and my battery does not seem to last more than three days without me driving it.
maybe i knackered the alternator when i had the sub in previously??? help please..
have a cda 9853r headunit
car is a MK1 GOLF CAB 1.5
have an alpine amp around 500w rms
4 gauge wiring
4 6x9s alpine and infinity at the moment just for some crisp sound..