"BOOM" noise when ignition turns off?

[RSR33]

This one has me scratching my head.

When I turn the car off when the volume is up a bit the subs make a loud boom or pop noise. I thought at first it may have been a poor earth to the amp, but after reading the forums I have it earthed to the same point everyone seems to suggests (using the same point as the battery is earthed)

If the volume is turned to minimum then it doesnt do it and if i turn the deck itself off it doesnt do it either, only when the ignition is turned off with the volume up.

The amp is an Alpine 1507, could this cause the problem? Front speakers which run off a kenwood amp dont do it which make me think its not the deck.

Any help any one?

[JR]

what sort of head unit is it? i had a trusty alpine headunit for 18 months never had a problem with it, sold it, my mate bought it and it did this in his car, it ended up getting sent away to alpine australia, and it turned out it was the alpine player didn not like the fusions amps in his car, and alpine fixed it free of charge

[RSR33]

iNTERESTING....Its a JVC Chameleon(?) deck, Had the same set up in my pajerio with no dramas, but in the line its another story.

I Thought it may be the deck but then why doesnt it do it to the front speakers wired through the kenwood amp?

[RSR33]

Cmon guys, someones got to be able to help??

[Fhrx]

Certainly.

I have installed many of those amps before and not once have I ever suffered from turn on/off thump.

Have you upgraded the battery negative as well as all the amp negatives? Try this for me.

1. Disconnect your remote wire from the head unit.

2. Run a seperate wire from your battery to the amp.

3. Turn the system on.

4. Now feed the amp with 12 volts on the remote.

If this turns it on and off with out the thump, then you'll know it's either the Kenwood amp of the deck. This is the first step in the process of elimination. I'll await your reply before suggesting anything else.

[RSR33]

Thanks, will try tonight.