As above really strange problem...

Basically fitted my sub / amp today to the Golf. Head unit is an Alpine jobbie, amp is a Phoenix Gold monoblock and subs are 2x 12" JL's in a double sealed box. I also run a Phoenix Gold Pro Line Driver in line. Had this setup in most of my cars with no problems.

Anyway, all wired in ok, when turning on everything powers up fine. If the volume is set to 0 on the stereo (ie - no noise) as soon as you go up a notch to start turning it up you get a loud thump through the subs (only one thump). Once the volume is up a little and further adjustments are made its fine. If you change track when the track starts it thumps to begin with. Its as if its only when there is no noise --> first bit of noise.

Things I have already tested:

Bypassed the Pro Line Driver - made no difference

Ran another RCA lead outside of the car from head unit to amp - no difference

Tried another RCA output on the Head unit - no difference.


Any ideas? Could it be a bad earth to the amp? Fooked head unit? (not sure on head unit as it done it on all 3 RCA channel outputs?)

Cheers
Chris