Installed an Alpine head unit, But getting turn 0n thump from factyory subamp?? | Ford Explorer Forums - Serious Explorations

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Installed an Alpine head unit, But getting turn 0n thump from factyory subamp??

New Ford Guy

New Member
August 20, 2006
Reaction score
City, State
Moncton, New Brunswick, Canada
Year, Model & Trim Level
2003 Eddie Bauier
Hi Members, I installed a Alpine 9835 head unit in my 2003 Eddie Bauier with the proper Metra wiring harness with the factory sub input. But i'm getting turn on thump from the factory subwoofer amp. It Only thumps when turned ON not when turned off. I tried manually delaying the amp turn on with the blue amp turn on wire....we still had the THUMP?? So I unplugged the RCA's from the head unit to the subwoofer connection(to check for ground loop)...we still had Thump?? Anybody else had this problem? Anybody have a Solution?
I Have the Audiophile factory system with factory Sub.(only the sub has the factory Amp). I just need to get rid of the THUMP !!!

Thanks in advance...New Ford Guy :exp:

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I used to have the same problem when I had my old system in my truck, have no idea what caused it. Gonna be putting a new system in my truck and am curious as to what causes the turn on thump.

Anybody have any answers????

I dont think its anything to be concerned about, start a computer on with the speakers on and you usually get a thump. Might just be from turning on, first bit of power that goes to it, did you try turning it on without the head unit on and see if it still thumps?

I had the problem along time ago and I was told that the preamptive outputs were bad in my head unit. I replaced the head unit and problem solved.

If you've already tried unplugging the RCA's, the only thing I can come up with is there is something wrong with the amp.

In pro audio, the thump, or in the case of pro-audio, pop, is caused by the amp being on before the audio source, in this case the headunit.

In this case I would say your amp is screwed up however.

Id be curious to know if it happens to thump if you just turn the amp on manually (jump the amp on wire?).

I'd venture a guess that it comes from the "meshing" of sorts between the aftermarket head unit giving the factory amp turn on power, whilst the factory amp is already turned on on. The remote signal delay from the Alpine would be fine for aftermarket amps designed for it, but if what im thinkin is happening is that the factory amp is on before that.