How to bypass factory amp?

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Joeydreamz
Posts: 1
Joined: Mon Feb 06, 2023 12:37 am

How to bypass factory amp?

Post by Joeydreamz »

Hello.

I just bought an '03 Vibe.
Pulled my radio kit/harness from my totaled '04 Matrix & transferred to the Vibe, plugged right in & everything lit up but no sound from head unit. Realized the Vibe has a factory amplifier under the seat. Is there a plug-and-play harness that will get my aftermarket CD player working? Do I need a line level converter somewhere in line?

Also, what if I just want to bypass the amp altogether?
I have brand-new 4-ohm coaxials for the rear door & new JBL component speakers for the front doors that I'd bought for the Matrix, but I understand that the factory amp drives the factory speakers at 2-ohms. I don't want to be stuck using paper speakers just because of some low-power amp I don't want to use anyway. Anyone know which wires are what at the amp (esp. the speaker outputs), or is there a by-pass harness?

Thanks!
Joey
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joatmon
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Joined: Fri Mar 21, 2003 5:19 am
Location: SMC MD

Re: How to bypass factory amp?

Post by joatmon »

Welcome to genvibe!

I haven't seen anyone cite a pre-made amp bypass harness

Some people have needed to use a level converter between an aftermarket head unit and the factory amp to eliminate loud pops, but I never went aftermarket head unit so I don't have first hand experience with that.

The attached gif shows the pinouts/connections from the factory head unit to the factory amp. It's possible that getting sound out of what you have may be as easy as connecting up what the diagram calls "Antenna Amplifier Positive Voltage" which I assume is a 12V to turn on the amp when the head unit is turned on (but that's an assumption) Diagram doesn't show it, but you also need to run that to the antenna base, or your radio reception will be poor (although I don't know if that affects AM, FM, or both)

If not, then the pic should give you a clue on how to cut and jumper wires to bypass the amp altogether.

03 Vibes had an optional package called "Moon & Tunes" which included the moon roof, the amp under the front passenger seat, and tweeters in the front doors at the side mirrors. For what its worth, the crossover for the door tweeters was internal to the factory amp.
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SlammedNiss
Posts: 505
Joined: Tue Apr 02, 2002 1:11 pm
Location: Chitholé, KS
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Re: How to bypass factory amp?

Post by SlammedNiss »

Would this one work?

https://axxessinterfaces.com/product/AXABH-TY1??

You'll probably still have to run 4 sets of speaker wire from the dash to the OEM amp though so I still wouldn't consider it a "bypass harness".
2003 Matrix Xrs Automatic - SOLD :'(
2011 Rav4 Sport
chromelampshade
Posts: 59
Joined: Mon May 23, 2022 2:50 pm

Re: How to bypass factory amp?

Post by chromelampshade »

Typically doing a factory headunit swap with a different headunit in the vibes can be tricky, since different units output different high level voltage, it can be tricky finding one that works with the factory amplifier. As for the headunit not outputing any sound, did you verify all connections? not all wire colors on harnesses arent always the same, do not ever match by color, match by verifying what wire is for what (LF, RF, etc) considering you pulled the unit from your totaled vehicle, chances are the unit could be damaged, if not, check the fuse on the headunit (if it has one).

There is many ways you can go about upgrading the sound system, you can use line out converter, but if I were you in your case, try to find a decent 6ch headunit, or, 4ch, utilize the preamp rca outputs on the unit, dont bother with the high level speaker wire, just wire the main connections (12v constant, remote, ground, etc.) and use the 4ch rca to signal to a 4ch amplifier (unplug and remove factory amp) and then, utilize sub out preamp, to power monoblock amplifier to drive a woofer, or you can buy a 5ch amplifier to make it easier. From there just normally run wire from the amps to your speakers, and walla.

sounds complicated and alot of work, but honestly its worth it. And i can tell you from experience working with the vibe has been extremely easy.
We do live in difficult times and things are expensive, but if its something you'd be interested in (its a nice hobby too!) im always more then welcome to help you find the best quality for a budget, and help you work your way through getting some awesome audio.

Me personally I went through 2 headunits, going to get a new one soon, a double din touchscreen. ive added a sub amp, and pretty soon going to remove the factory underseat amp and put a 4ch amp to drive door speakers etc..



If you want to go a easy route, (after you solve headunit issue), you can find some 2.5ohm final midranges that are made for factory amplifiers. But even then me personally I am running 80w rms 2 way components on my doors and a tweeter upfront (4ohm final), and the factory amp certainly gets the job done considering the output ratings, aslong as your speakers are 90db+ sensitivity, and around 30 - 50wrms, you should be happy with it
2003 Pontiac Vibe AWD Base "Bass Mobile"
320A Autotech Engineering Alternator
1/0 Oversize Sky High "Big 4"
Optima Yellow Top 55aH AGM
B2 Audio Rage 2500.1D V2 > DDX 10
6th order bandpass series tuned 27/50hz
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