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Bypass / Replace OEM Amp

V

vtav

Full Member
Joined
Jun 24, 2002
Messages
14
There is a GM amp behind the glove box. I have upgraded the factory head unit, but it still feeds through this factory amp. I probably could find a way to hardwire and simply bypass the amp and use the clean power from the new head unit. If the amp is the same quality as the rest of the GM system, it should go!

Another solution would be to replace that OEM amp. If I mount in the same / near location, I could use the amp factory output harness that runs to all speakers. This would simplify the amp installation and prevent me from running wire from the amp to every speaker.

Any ideas???
 
Hey Goo . . and other audio experts . . . where are you!

I didn't know that the Av had an external amp - thought it was all in the head unit - we need some expert insight!
 
Yes, grab a flashlight, open the glovebox and take a peak behind it. If you went to an aftermarket head unit (including using the on-star adapter) and plugged into the factory wiring harness to feed your speakers, you are running through the OEM amp.

I have no data on the amp itelf. I assume it is not a high quality unit based on my current results and am looking for ways to either bypass or replace with minimal installation time.
 
wrchism said:
Hey Goo . . and other audio experts . . . where are you!

I didn't know that the Av had an external amp - thought it was all in the head unit - we need some expert insight!
Click to expand...

Sorry about the delay. ?

I am normally busy over in Accessories or Cruises ;D ?The real experts on this stuff are carrerarod and Rocknz66. ?

Yes, vtav is correct about the location of the amp. ?It is a pain to get to if you are thinking about feeding the factory wires from a decent AMP. ?For the best results, we have run new wires to the speakers from the new AMP. ?Hopefully, you are upgrading the paper factory speakers for some with more acoustical sound and depth. ?Replacing the factory speakers was the least expensive and the received the most return of my audio upgrades.

my .02 ? :rolleyes:
 
I guess you could bypass the amp all together but I doubt you will be happy with the results.

Not sure I would mount a new amp in the same location either. Consider heat and ease of accessibility to make any adjustments you might need to make. Also, most modern amps are pretty big and the manuf. usually recommend it mounted flat with enough room for the heat the exit.

Using the wire harness may save you time but as you clearly realized, the wiring is as cheap as the rest of the system.

My $0.02.... ;D
 
I just put a new amp in my AV and it is under the center of the rear seat. Fit there fine. My next addition will be a Sub woofer which will fit under the driver side rear seat. I am still thinking about a new head unit. I am looking at 2 models..Both Pioneer. (it has to be a Pioneer) a friend works there so I can get employee price.approx 45% off.) The first one is a large radio similar to the one that comes with the truck. My second choice is an AM FM CD DVD (P7000) radio. I already have the Pioneer satelitte radio. I am toying with the idea of adding dvd screen to the back seat. Any suggestions? I do want to keep the Onstar system working also.
 
I'll check out if it is possible to attempt an aftermarket amp in the stock location.

The location under the rear seat with running new speaker wire is more work than I wanted.

What subwoofer did AEGIS find that could fit under the driver's seat?

For what it is worth: I replaced the factory head unit with MP3/CD + 10 disk changer in console + all speakers and the system sounds magnitudes better than stock.

Shame on GM for putting such junk audio in a $38K vehicle! :D:
 
I'd be curious to hear if you come up with a solution for getting an aftermarket amp in the stock location. As I mentioned before, seriously look at the heat dissapation issue. The harder you push your system, the hotter the amp will get. You must ensure that your amp stays cool enough or it will start clipping and shutting down. Heck, if Goo had his amp mounted in that location I think he would melt his whole dash off! >:D

I agree with you that GM should be ashamed for putting such a dinky system in the truck. But if it makes you feel any better, you should see what they put in a $100k Porsche. Worse than what GM gave us!

Keep us posted!
 
Yep . . I too am dissappointed in the Av's sound system - my little Saturn's stock system is much easier on the ears. I'm not looking to shake the earth - I just want a system with good performance at reasonable listening levels. My biggest complaint is the Av's boomy base - is this GM's feeble attempt at subwoofer imitation? Will swapping speakers fix this - or is more serious surgery necessary to get what I want?
 
wrchism: IMHO to take care of the "boomy" sound, I believe replacing the amp first might give you want you want.

the speakers are not that bad in the AV. the amp quality is worse that the speaker quality and the amp is the weak link. a couple of years ago i took the phased approach to replacing the system in my '00 Tahoe (same system) I was going to rip the speakers out first but a good friend told me to do the amp first with the stock speakers and see what I thought. well he was right. a new amp with stock speakers completly transformed the system (i also did a new head).

now you won't win any competitions with this approach but it sounds like this is not what your goals are. I feel pretty confident that if you were to get a decent 4/5 channel amp and use the stock speakers you would be more than pleased. Just keep in mind that if you have onstar you might have to do a little more work to get your whole system dialed in.

good luck.
 
Carrerarod . . thanks for the input - I was hoping for the easier route, but maybe that's not to be. So, I'll follow this thread regarding an amp swap in the stock location. No On-Star, but I'd probably keep the stock head unit. Again, THANKS!
 
I put a 10" sub behind the passenger seat (rear) Had a box molded to fit seems to work fine.
Click to expand...

Aegis could you be a litlle more specific. I am desperately trying to find somewhere to put a sub. Did you put it under the passenger seat.

Anyone else got any new ideas. I'm not ready to give up my centre console yet.
 
Talk about a BAD system - the stock Blazers are HORRIBLE. The Av sounds awesome compared to the Blaze.... So good, I still have $1800 worth of stereo stuff I yanked out of the Blazer that I haven't feel the need to start installing yet.

When was this amp added by Chevy? Did 2000 Blazers have it? (it had the same looking hardware throughout, just different locations)

I imagine that if the stock amp will hamper a system install, someone will have a bypass harness or some instructions on how to bypass it, soon enough. It shouldn't be that hard to figure out at all with a simple schematic of the stock stereo system.
 
I think this is the same problem that i'm having with my new sound system. I recently installed a new 5 channel amp and replaced all my speakers with MB Quartz...I kinda went overboard...the sound from the speakers is great but now I hear this whistling/fan-like noise every time I press on the gas. I was told that the problem was with my GM head unit. However, I also heard that you can fix the problem by bypassing the factory amp. If anyone has had the same problem and knows how to fix it, then please let me know what I can do.

 
I think the answer lies in a unit called a PAC OS-1. (found at www.crutchfield.com ) According to the units description, it interfaces between your new head unit and onstar. It provides speaker outs for onstar so you can now use your pre-amp outs off your radio to go to a new amplifier...bypassing the amplifier behind the glovebox. Youll just have to run all new speaker wire to your door speakers.

This is the route I am going next month. Hope this works and hope someone tries it and lets me know.



 
sleepyhead4: if you installed an aftermarket amp then you are are not using the OEM amp. your wiring should go somthing like head unit to amp and then amp to speakers. if you have onstar then you have the OS-1 and have to conenct a few wires there. with an aftermarket amp you will probably need to install a separate speaker for the onstar.

anyways, i hate engine whines. there are hundreds of possibilities. a couple of ideas. make sure the power wires for the amp are routed cleanly as far away from the engine or anything that draws power like A/C, etc. Make sure you got a clean ground. This is important. Take a look at your amp. you should have gain adjustments. you might have to adjust these, in my porsche i had the input gains on my equalizer too high and would cause a whine. the fix was to decrease the input gain on the processor/equalizer and increase the output gain on the amplifier to keep the same decibel levels.
 
Hey Aegis! I'm going the same route as you. It goes in next week. I'm putting a low profile 1100 watt Class 'D' amp (much less heat) under the seat behind the driver for the 15" sub-woofer and it's lil' sister under the seat behind the passenger. I'm having my installer buddy do it due to I just don't have the patience to mess with wiring like that any more and he'll do a good job. I already replaced all 4 door speakers with Infinity 652i's ($200). An improvement, but just not enough power for me, esp. with the windows down and sunroof open. The sub will be moveable so it can go in the box or in the cab with me when the seats are down in back. The box is kinda cool, it's done up in box liner type material so it's rough and won't slide around. Plus there should be enough room (and power!) to add another setup like it if I need more. When I get this all done I'll post a review and maybe some pics on picturetrail.com or on another site I'm building. Stay 'tuned'! (y)
 
carrerarod: Is it possible that the engine whine might be because the new amp is going through the old amp? I don't exactly know how they installed the new wires but it looks like the new wires are not going straight from the head unit. Maybe the problem is from the conversion of the old wires into the new RCA wires via the harness...the engine whine is really driving me nuts. Thanks.
 
Sleepyhead3: you might have to try a few things to isolate your problem. I am assuming you can reproduce the "whine" at will so this is what I would do 1st. I would try to rule out the amp power/ground. Disconnect the RCA cables from the amp to the headunit. rev the engine and see if you hear the whine. if you don't then you know its somewhere in the RCA run or wires with the headunit. if you still hear it, might be the ground to the amp (easy to check). i doubt it's the speaker wires.

you never did mention if you have a stock or aftermarket head. assuming an aftermarket, the RCA cables from the amp should run directly into the preamps of the head. no old wiring there. if you have OS-1 there will be a few splices from the head to the OS-1 and a few out of the OS-1 but none of these should be the speaker wires. you should have a standalone speaker for onstar.

the only other thing i can think of this early in the morning with only 2 coffee's in my body is turn down the volume on the OS-1 itself. It might be acting as a processor and distorting the signal.....

Good Luck!
 
My 10" sub is under the passenger side rear seat. The box was molded to fit in the space cut out under the seat. The amp is next to the speaker> I will put the dvd behind the drivers seat rear..
 
STOCK AMP REPLACEMENT:

I scoped it out and it DOES look very feasible.

The Alpine amp I had in mind measures about 9x10x3. It will fit behind the dash. A custom bracket could use the stock mounting locations.

As far as heat dissipation, I think this could be better than under the rear seats. Heat rises and there are plenty of places for the heat to escape the dash. If you are really cranking up the power, you could open the glove box for more air.

It would be really trick to do this location, but I don't have the time to play with it right now. I think an audio expert on this forum would be up for it. If you are successful, let us know!
 
Too get rid of the damaging heat, is there any way to install some type of fan similar to what is used inside computers to cool the CPU and other components?
 
Let me get this straight...If I buy an aftermarket head unit with aux input, OS-1, and an amp, I can efectivly bypass the entire stock system and still have On Star work through the entire system?

PS I will repace speaker cords too obviously since new amp install.
 
Wiki: that is correct. I have an aftermarket head unit w/ OS-1 and installing a US Acoustics amp this week. This setup will bypass everything that was stock.

Keep in mind one thing, you will need to install a couple of external small speakers someplace for the Onstar. The Onstar will not play through the factory speakers with this setup. I may have a workaround to this but won't talk about it until I can verify that it works.
 
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