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

 

im not an expert, but i would try another head unit, cos you say it does it from zero volume going to 1 and when changeing tracks, gary

 

Have you made sure the BLUE remote wire is connected correctly???

Sounds like you have a wire round the round way somewhere which is causing interference

 

Check the earths on the amp with a multimeter, also the head unit earth

Could be so many things tbh

 

Fook knows!! I dont think it will be the head unit as its only about a year old and never had any probs with it. As you say it could be loads of things. It does sound like an interference type thump (hence trying the RCA's outside the car) but could be something behind the head unit I suppose. On Alpine units is it the blue/white or the blue that is remote turn on? (the other is the aerial I think).

Chris

 

Blue is remote

 

USE A MULTIMETER!!!!

 

bad eirth to the headunit

 

If I use a multimeter what current should I expect through the earth Stu?

Mark - not the head unit ground as its been in the car for months....

Chris

 

the thump is the amp kicking in
you need to stop the sudden power surge going to the speakers from the amp, possibly crossover isses

 

but it hasent had an amp on it till now

 

more than likely a bad earth had this on my system and everytime the amp came on a thump came from the subs turned out that the earth connection on the amp had worked loose slightly

 

Deffo bad earth,had this myself. Not as bad as my wiring fault last week though! i put an amp and bass tube in my van,and managed to cross my live and earth feeds to the amp. the head unit coming on of it's own accord was interesting.

 

Well ive just been out there, checked the remote and all is good (i've even run a remote lead on the outside of the car direct to the amp to confirm there is no short!). Also changed the earth for an even better connection than there was and unfortunately no difference . So looks like its either the head unit or the amp??

Chris

 

i had the same prob for ages i just put the amp on a switch now so i can turn it off , dont notis it when the amp ect is on nice and loud so jts left it to get on with its self lol