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The audio sounds terrible in my Impala. Output is very weak, though all speakers seem to be working. I've noticed that this happened once before last year on a cold day, but then went back to normal. I have the factory deck with the trunk amp. Is this an amp issue, or a head unit issue. Hoping someone knows. Most of the posts i've seen have to do with no sound at all.
 

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swapping the trunk amp would probably be the first step, actually with the power off unplug the electrical connectors and squirt with electrical contact cleaner on both halves of the connector . I do this routinely under the hood to all the metri-pack connectors...its like a tune up, hopefully it will fix your issue. I would not buy another amp see if maybe a salvage yard will let you swap knowing you will buy the amp if that is what is wrong.
 

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Mr. Handy
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Fyi: the wiring for the amp is different on different years. Don't just grab any one.

If the amp is indeed bad I would just bypass it. The trunk amp is less powerful than the stock headunit.
 

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Did you ever come to a resolution billeatman? I am having the same problem with very quiet speakers in my 2004 impala. I read alot online about people having no audio relating to a water leak corroding the amp power wire harness on the rear passenger side floor board, i checked it and mine seemed fine and was not wet, so im at a loss on what to do... Is bypassing the trunk amp easy and does it disable the rear speakers? Sorry for reviving an old thread, but I figured this would be better for anyone searching on here without making a whole new thread.
 

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I figured it was the amp and it was, after doing a amp bypass the radio now works, but the sound does not sound that great... would replacing the amp make the sound quality better?
 

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I figured it was the amp and it was, after doing a amp bypass the radio now works, but the sound does not sound that great... would replacing the amp make the sound quality better?
As I recall, there's a signal or wire into the head unit from the amp telling the head unit the amp is present. In response, the head unit sends out lower voltage signals to the amp. With the amp not there, the head unit outputs higher voltages suitable for driving speakers, but not as powerful as what the amp can do.

So that's probably why "the sound does not sound that great".

A new amp should make it sound louder, and hopefully better :)

Doug

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As I recall, there's a signal or wire into the head unit from the amp telling the head unit the amp is present. In response, the head unit sends out lower voltage signals to the amp. With the amp not there, the head unit outputs higher voltages suitable for driving speakers, but not as powerful as what the amp can do.

So that's probably why "the sound does not sound that great".

A new amp should make it sound louder, and hopefully better :)

Doug

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I will look into either a replacement factory amp on ebay (altough i've heard it is not that great to begin with) or an after market amp that is hopefully cheaper, I found this "conversion kit" online that supposedly lets your plug the GM amp connectors into some kind of universal adapter Car Stereo Add an Amp Amplifier Adapter Interface for some GM OEM Factory Radio | eBay any opinions on this?
 

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I will look into either a replacement factory amp on ebay (altough i've heard it is not that great to begin with) or an after market amp that is hopefully cheaper, I found this "conversion kit" online that supposedly lets your plug the GM amp connectors into some kind of universal adapter Car Stereo Add an Amp Amplifier Adapter Interface for some GM OEM Factory Radio | eBay any opinions on this?
I can't say I have any experience with it. I'm curious how it's wired together. The factory head units have 4 signals going to the amp, I think, so I'm curious how the two RCA jacks are wired in.

FWIW, I'm old school on this sort of stuff. I will typically strip the insulation off and solder new wires into the old ones , and avoid using new connectors. But, if you can get the right adapter cables, no doubt, it can save you some time and effort.

Doug

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@plano-doug on the 2000-2001, there is a 27K|47-pf network to ground on the AMP SENSE pin that causes the head unit to output differential line level signals. I don't think this signal is present on 2002-2005.

4-singals...kinda. There is differential in and differential out, so 8 wires. it looks like in the AMPS with the 12 way connector, there are front tweeter amplifiers adding 4 more wires.

The 2000-2001 ha a 6-way and 24 way connector.. 2002-2005, I believe has a 12-way and 24-way connenctor and both are wired very differently.

The corrosion behind the passenger seat doesn't exist on the 2000-2001 Impala.

There is a $5.00 part available from your dealer that will fix the water leak on a 2000 Impala anyway, it will take 20 minutes to install if there are no issues with the cowl trim. I had to repaint mine and add new weatherstipping. The water comes in through the cabin air filter. The dealer had it in stock.

For the 2000-2001 amp the amp has 4 LP filters and notch filters for each speakers. The notch filters are probably at the cabin resonance frequency. it looks like the 2002+ amp is speaker level inputs only. I know of 3 p/n's for the 2000-2001 amplifer and the 10309548 is supposedly the best sounding. I might figure out where the notches are.

I've located a service manual for the 2000-2001 amps and I believe I know why they die. It's probably the same reason why the 2002+ Amps die. My experience is that a jump start is likely to kill the amp. Two personal experiences. The amp may also turn on and off depending on temperature.

I'm in the process of making a test harness and test jig for the 2000-2001 amps.

At this point, I am nearly 100% convinced I can prevent the 2000-2001 amps from dying by installing 2 components on the main PCB and making a small PCB and installing it in an unpopulated location. The same (circuit wise), but different fix (implementation), can probably be applied to the 2002+ amplifiers. That space is occupied, but a flex PCB might work.

The turn-on circuitry is suspect when all channels die, possibly together with the amp IC's. I've already seen that. When one channel is out, I'm hoping its an amplifier IC.

 
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