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I need an expert opinion on amp install

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Old 05-09-2008, 12:30 PM
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Originally Posted by grandprix104
When the amp is plugged in it sucks the battery voltage down pretty quickly. Even with the car running, the volt-meter on the dash is well under 12v, but jumps to 14 when the amp is unplugged.
That is not right. No amp should do that. You definitely have a problem in the amp itself. Get your money back.
Old 05-09-2008, 09:01 PM
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Test for DC voltage on the speaker outputs of the amplifier. Use any DC voltmeter, set to a range of about 50 volts. If the meter pins negative just reverse the tester leads on the speaker outputs.

A blown amp is pretty easy to diagnose, you'll usually get a power supply rail at the speaker output.

Also, you said you're using high-level inputs on your amp, so you're running the wires that used to feed your factory speakers to the amp'* high-level inputs, is that correct?

Some of the factory systems use a common signal ground, while some amplifiers may require an isolated signal ground. In order to convert the factory common to isolated, you can use a device like this:
http://www.sonicelectronix.com/item_...OEM-GM21C.html
(There are different models depending on what factory head unit your car has.) An additional advantage of using this type of adapter is that it will supply a line-level signal source to your amplifier.

Can you possibly use any small source, such as an iPod or walkman-style CD player as an input to the amp on the line-level inputs of the amp? That would be a better indicator of whether your amp has a problem, or whether you just goofed the connections.

I personally think the advice to change your power cables to the amplifier, while well-intentioned, have nothing to do with your problem.
Old 05-09-2008, 09:22 PM
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Originally Posted by Bugsi
Can you possibly use any small source, such as an iPod or walkman-style CD player as an input to the amp on the line-level inputs of the amp? That would be a better indicator of whether your amp has a problem, or whether you just goofed the connections.
I did. It works ok off the RCA input from my Ipod but still goes into protect when i touch the gains.

Also, I spliced into my old speaker leads so i have a wire coming from and one going back to each speaker.

Does anyone know what system, isolated or common, the 01 base model stereo with cd/tape uses?
Old 05-10-2008, 02:33 AM
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Is there any range on your gains where the amp does not go into protect? All the gains are for is to match the level of the input signal to the input stage of your amp. Your gains probably have significant gain, and if you feed a line level signal (on the order of 1 to 3 volts peak-to-peak) to it and turn up your gains, it'* probably normal to be able to trigger it into protection. You just need to find a range that works correctly, then dial them in to the higher end of that range.

You should still test the speaker output terminals on the amplifier for DC voltage. If it'* working, it should have zero across each terminal pair when you have the volume turned all the way down. If you have significant DC voltage, then you have a bad amp.

I think if you're going to run an aftermarket amplifier with your stock headunit, you'll need the adapter that I linked to earlier. That will maintain your stock wiring harness but give you line level outputs tapped off your head unit. You'll need to run RCA'* from that to your amp. It'* okay to use your stock speakers with your amp (if you must), if you already cut the wires, just put some tape or crimp one half of a wiresplice butt-connector on the ends that come from the head unit so they don't short out on any of the car body. (Or with each other. Do NOT connect the loose ends together!!)

But I think there'* basic differences between your stock speaker output and the inputs on your amplifier. Your amp no doubt has a single-ended input referenced to ground. The output of your stock car head unit may be a bridged differential pair where the + and - lines of each speaker pair are a signal and inverted signal pair, rather than a signal and ground for each pair.

Presuming that'* the case, you'll need the PAC adapter to run an aftermarket amplifier with your stock head unit. Fortunately, they're relatively inexpensive at the company I linked you to. I just bought an adapter for my wife'* 2001 Grand Prix GT with the Bose system, in hopes of keeping the Bose system'* integrity with the heads up unit, steering wheel controls, and OnStar system, while still using a better amplifier to feed better speakers. The PAC adapter is absolutely necessary to do that. I think you'll need a PAC adapter too.
Old 05-13-2008, 01:36 AM
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GrandPrix104

How do you have your speakers wired on the amp ?
Each speaker to an individual channel or do you have multiple speakers hooked up to each channel.
Example: 2 speakers on one channel or bridged across 2 channels.

How are your speakers wired to the amp and what are the restances of the speakers 2 Ohm, 4 Ohm etc.

Get rid of that residental ground wire and use a piece of proper Auto power cable the same size as your main power feed for the amp. The wire only needs to be 4 feet or less and should only run you about $10.

Also you should never "Center Tap" a Battery with power wires.
The Amp needs to be able to dump power to ground as fast as possible.

Relocate your ground wire to the body or frame and sand the paint to shinny metal

My guess is that wiring is the issue with the amp or you might just have really bad luck.

Regards,
Dutch
Old 05-14-2008, 10:26 AM
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ok I havnt had time to mess with this much lately but I'll answer some questions.

first I am using aftermaket speakers rated 50w @ 4Ohms for all four channels. Each speaker is wired to an individual channel. The sub is rated 200w @ 4Ohms. The speakers were each wired directly to the head unit with the factory wiring. Now I have spliced in between the speaker and the HU and run signal wires back to the trunk for the front speakers and done the same on the rear speakers as well. At any rate the amp goes into protect the moment you adjust the gain on Amp1 but you have a litttle leway on amp2/3. If the music hits a low bass note the unit may go into protect anyway. It does this on HLI or Low level inputs. I will test the speaker outs when i find my multimeter. I want to know more about line level converters though. That is how i had my RF amp hooked up as it didnt have speaker ins. Problem was it sounded like crap and had a bunch of other adjustments that I couldnt get right. I'm not a big fan of them. Thats why I bought an amp with speaker Inputs. PayPal still hasnt gotten back to me about getting my money back. I am thinking of getting a HiFonics Zues 5 channel amp for the same price that is new. Any thoughts on that brand?
Old 05-14-2008, 11:33 AM
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of the 2, i would take a new amp over refurb. anymore both are mass produced amps..so you don't have the quality of the old school days...sigh...

ive never dealt with inputs you speak of. I could never see spending money and time into a stereo to retain a factory deck. deck can make a ho hum stereo into a omg stereo quickly....just opinion..everyone is different though.
Old 05-14-2008, 12:04 PM
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I have to agree with the previous response. While this is sidetracking a little bit, -is there some reason why you're keeping the factory head unit? You could do a whole lot better than the factory unit, and you can get real line level outputs intended to drive an amplifier, instead of converting speaker outputs into amp inputs just to drive speakers again.

If it'* possible, seriously consider an aftermarket head unit. You can also get much better functionality in an aftermarket these days, with support for mp3CD and good iPod connectivity.
Old 05-14-2008, 12:51 PM
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exactly. depending on your tastes, if you are on budget, some shopping on ebay for used can get you into a nice unit as well. i have been extremely pleased with my kenwood excelon decks over the past 6 years. i have had probably 3-4 of them. i have 1 in my fun car and 1 in my daily. i will say though, stay away from D Mask decks..problems there..the newer ones are away from it though. that is reason for so many in years past..d mask messed up. i think i gave just under 100 for each my cd players i have now. both excelon models. Thing i like about them is that they have built in crossovers in them for highs and sub as well as sub output control. i pod connection, mp3 ability..so on. list is looooooong. plus, you can switch them to red as well....not all red display, but primarily red. to each their own though.... i have owned pioneer premier, sony mobile es and kenwood excelon.....i have always liked my kenwoods best. price per feature is good.

anyway, something to consider. for another 100 lets say...your stereo could sound WAY better.
Old 05-15-2008, 02:59 AM
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Grandprix104

When you say you have "spliced in between the Factory HU and the Speaker" what do you mean ?

Did you cut the wires in half and connect to the speaker side and run that back to the Amp ?

OR

Did you just tap into the wire like a "T" connection ?


If you just tapped into the wire without cutting it in half then you are showing the Amp the resistance of both the speaker and the HU.
This would cause the Amp to go into protection.

Also how are you getting your musical signal back to the amp, which speaker wires did you tap into for signal and how many pairs ?

Regards,
Dutch


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