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Running 12G power wire through firewall for stereo 45W amp

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Old 03-08-2019, 09:21 PM
  #21  
auburn2
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Ok a few things.

First if you are using a factory bose head unit and speakers this can get complicated real quick. I would do more research if you are going this route.

If you are using a good aftermarket head unit your sound quality is going to be mostly dependent on the speakers. Problem is you will likely ruin good speakers in a year or so if you don't have an amp. Distortion destroys speakers, especially at high volume. Cheap speakers never sound good so they don't deteriorate. Good speakers with a good head unit but without an amp are going to sound great the day you install them but degrade quickly (months to years) due to distortion. Any good amp will clean that up and they will last indefinitely as long as your amp is powerful enough for the volume you run. Always buy more amp than you need, the rating on the speaker is not really relevant. Some people have say 50 watt speakers so they think buying a 100 watt amp will hurt the speakers. It will actually be better to have a 100 watt amp with it running at half volume than a 50 watt amp and running at max for the same sound level. The latter will destroy the speakers a lot quicker.

When it comes to your power wire the right way to do it is wire directly to the battery and drill a hole in the firewall and install a grommet. If you cut into an existing grommet you are asking for a leak in my opinion.

You should wire directly to your battery to avoid noise. Ideally you should wire your head unit and amp to the same power and ground wires. That can be a lot of wiring so if you want to try it with the head wired to the stock wires go for it, but if you get noise then wire them together.

Using an amp is going to result in more noise and less distortion compared to not using one in the same conditions. Noise is different from distortion. Noise is do to interference of some sort, it is a "real" signal your amp is picking up from something else and will amplify it. A amp has a higher sensitivity, and therefore picks up noise easier. Distortion is based on the quality of the amp, its dynamic range, spectral purity and how loud you run the volume. Distortion is related to how much the signal degrades when it is amplified, the louder you turn it,the more you push the amp, the more it distorts. This is why you want more amp than you need. You can usually eliminate noise with wiring and shielding. You can't typically eliminate distortion other than buying a better or higher powered amp. As I said earlier, distortion will kill good speakers, noise typically won't unless it is outside the frequency response of the speaker.

Last edited by auburn2; 03-08-2019 at 09:30 PM.
Old 03-11-2019, 10:27 AM
  #22  
hcbph
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Originally Posted by Roys92BlackRose
If I remember right there is a 12 V tap underneath the console where the seat switches are for accessories and such. I don’t know what the fuse rating is on that circuit but it is worth checking out because it is a convenient point of connection for a small amp.
I don't know about a power tap under the console, but if yours is like mine, power seats are controlled by a 30 amp circuit breaker in position 20 of the fuse block (4th from the top, closest row to the front end). It controls the power seats, hazard lamps and power locks.

Last edited by hcbph; 03-11-2019 at 10:28 AM.
Old 05-26-2019, 06:47 PM
  #23  
colter
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I got a Crutchfield 12AWG amp wiring kit and will put a 15AMP fuse in it. I was able to fit the wire through the bottom of the rubber sleeve of the hood release cables and pass the 12AWG wire through the firewall. Though I did heat shrink down two layers of tubing on the power wire in the area that passes through the firewall to give it extra protection. Plus the covering of the Crutchfield amp wire kit looks like silicone, which I think can tend to crack over time.

I'll probably get an Alpine 1DIN head unit. Though don't like the idea of a USB drive sticking out the front.

The Alpine 445U 50W small amp uses a 16AWG wire for the power wire in the Alpine wire harness. Which will connect to the 12AWG wire I'm running. I was looking at connecting that power wire to the 12V Junction Block behind the battery and would connect the headunit to the factory power wire.

Would that small 50W amp be small enough of an amp draw that it would be safe to connect there to that 12V Junction Block? I'll connect both amp and headunit to the same ground wire that'll go to the nearest ground junction at the front of the door.

I was reading around and saw that if you connect too much stuff to that 12V Junction Block, that it could overload the large wire that connects to the battery. Specifically the comment by DUB in this thread:

https://www.corvetteforum.com/forums...o-battery.html
Old 06-11-2019, 04:30 PM
  #24  
bud40oz
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Originally Posted by auburn2
Ok a few things.

First if you are using a factory bose head unit and speakers this can get complicated real quick. I would do more research if you are going this route.

If you are using a good aftermarket head unit your sound quality is going to be mostly dependent on the speakers. Problem is you will likely ruin good speakers in a year or so if you don't have an amp. Distortion destroys speakers, especially at high volume. Cheap speakers never sound good so they don't deteriorate. Good speakers with a good head unit but without an amp are going to sound great the day you install them but degrade quickly (months to years) due to distortion. Any good amp will clean that up and they will last indefinitely as long as your amp is powerful enough for the volume you run. Always buy more amp than you need, the rating on the speaker is not really relevant. Some people have say 50 watt speakers so they think buying a 100 watt amp will hurt the speakers. It will actually be better to have a 100 watt amp with it running at half volume than a 50 watt amp and running at max for the same sound level. The latter will destroy the speakers a lot quicker.

When it comes to your power wire the right way to do it is wire directly to the battery and drill a hole in the firewall and install a grommet. If you cut into an existing grommet you are asking for a leak in my opinion.

You should wire directly to your battery to avoid noise. Ideally you should wire your head unit and amp to the same power and ground wires. That can be a lot of wiring so if you want to try it with the head wired to the stock wires go for it, but if you get noise then wire them together.

Using an amp is going to result in more noise and less distortion compared to not using one in the same conditions. Noise is different from distortion. Noise is do to interference of some sort, it is a "real" signal your amp is picking up from something else and will amplify it. A amp has a higher sensitivity, and therefore picks up noise easier. Distortion is based on the quality of the amp, its dynamic range, spectral purity and how loud you run the volume. Distortion is related to how much the signal degrades when it is amplified, the louder you turn it,the more you push the amp, the more it distorts. This is why you want more amp than you need. You can usually eliminate noise with wiring and shielding. You can't typically eliminate distortion other than buying a better or higher powered amp. As I said earlier, distortion will kill good speakers, noise typically won't unless it is outside the frequency response of the speaker.

yes this for the most part is correct, until that day comes when you decide that song really sounds good and keep cranking it up until you melt voice coils, then you get a lot of smoke and the speaker stops moving entirely



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