Amp install
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=23737
Printed Date: June 12, 2024 at 7:53 AM
Topic: Amp install
Posted By: chan4202
Subject: Amp install
Date Posted: January 01, 2004 at 8:14 PM
I have a Rockford Fosgate 1001bd amp and Jl audio 300/4, which combine for 1300 rms watts. I dont know what gauge wire to use. The amps are going to be about 15-20 feet from the battery. I am thinking 0 gauge, but I would like to get away with 4 gauge if possible. Also do I need a capacitor? And if so, do I wire it to both ams, or just to the sub amp. Also what gauge speaker wire should I use and what type of rca's. I would think that the expensive rca's would be better than the cheap ones, but I just dont know. Any help would be great. Thanks Chandler ------------- Chandler Martin
Replies:
Posted By: bberman1
Date Posted: January 01, 2004 at 8:32 PM
You will be fine with a 4 gauge for your main power cable, as far as the cap goes the rule of thumb is 1 farad for every 1000 watts rms, so you would need a 1.5 farad cap but it never hurts to go larger. As far as the cap goes you do really don’t need one your better off investing that money into a high output alternator. However if you do install the cap you can install it before the amps distro block or inline with either amp. As far as the speaker wire goes you can use 16 or 14 gauge for your mids and highs, and 12 gauge for your subs. Their are several types of rca's out their that all claim to have the special patent that makes their brand better then the rest, but from my experience if you just get a decent set you wont be able to hear a difference between them and a $150 set. Personally I use Knukonceptz Krystal Konnectz series https://www.knukonceptz.com they have some excellent quality cables at reasonable prices.
Posted By: chan4202
Date Posted: January 01, 2004 at 9:48 PM
What size fuse do I need to use, The Rockford Fosgate amp says a 100 amp fuse, and the Jl audio amp says a 40 amp fuse. Do I add these together and get a 140 amp fuse? Or do i just get a 100 amp fuse?
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Chandler Martin
Posted By: bberman1
Date Posted: January 01, 2004 at 10:20 PM
From my calculations with 1300 watts rms you should be pulling about 100 amps.
Posted By: Alpine Guy
Date Posted: January 01, 2004 at 10:25 PM
you may wana go 2 guage for that amount of power and distance, it will just cut down on the resistance to a safer level.
Posted By: Durwood
Date Posted: January 01, 2004 at 11:25 PM
bberman1 wrote:
From my calculations with 1300 watts rms you should be pulling about 100 amps.
Even being generous and assuming the RF amp and the JL amp are 75% efficient, you're still looking at closer to 150 amps, not 100. And that's for the RMS load, not the peak load. I'd definitely go with 2-gauge for this. Scott Gardner
Posted By: Durwood
Date Posted: January 01, 2004 at 11:27 PM
chan4202 wrote:
What size fuse do I need to use, The Rockford Fosgate amp says a 100 amp fuse, and the Jl audio amp says a 40 amp fuse. Do I add these together and get a 140 amp fuse? Or do i just get a 100 amp fuse?
Go for at least a 140-amp fuse at the battery. You can go higher if you want - the fuse near the battery isn't to protect the amps, it's to protect the wiring in case part of it shorts to ground. Put the 140-amp (or larger) fuse as close to the battery as you can, since any wire between the battery and the fuse won't be protected from shorts. Scott Gardner
Posted By: fuseblower
Date Posted: January 02, 2004 at 7:46 AM
Looks like you have the wiring down but as far as a Capacitor you might want to save up a few dollars more and upgrade your alternator. Your car would love you for it.
Posted By: bberman1
Date Posted: January 02, 2004 at 11:49 AM
Durwood wrote:
bberman1 wrote:
From my calculations with 1300 watts rms you should be pulling about 100 amps.
Even being generous and assuming the RF amp and the JL amp are 75% efficient, you're still looking at closer to 150 amps, not 100. And that's for the RMS load, not the peak load. I'd definitely go with 2-gauge for this. Scott Gardner .
3 I can almost guarantee you if he used a 100 amp fuse he would never blow it. That setup will never draw anywhere near 150 amps
Posted By: Durwood
Date Posted: January 02, 2004 at 3:22 PM
Are you saying that the RMS numbers for those amps are BS, or that the amps are significantly more than 75% efficient? If we believe the RMS numbers and assume 75% efficiency (which I feel is being generous), then the current required by the amplifiers to provide 1300 WRMS is about 145 amps. Current required for peak output will be significantly higher than that. Scott Gardner
Posted By: Durwood
Date Posted: January 02, 2004 at 3:32 PM
chan4202 wrote:
What size fuse do I need to use, The Rockford Fosgate amp says a 100 amp fuse, and the Jl audio amp says a 40 amp fuse. Do I add these together and get a 140 amp fuse? Or do i just get a 100 amp fuse?
Just to make sure you're clear on one point. If you put a 100-amp or 140-amp fuse near the battery, that's NOT a substitute for the recommended fuses near the amplifiers. I can't recall if the 1000bd or 300/4 are internally fused or not. I just didn't want you to think that all you needed was a single large fuse at the battery. Scott Gardner
Posted By: forbidden
Date Posted: January 02, 2004 at 5:07 PM
If the amplifiers are not internally fused then he will need a fuse for each at the rear of the vehicle, a fuse of a value of 100 amps or greater than the combined value of the 2 amps should go near the battery. While it is true that even though the amps say they need 140 amps of fusing, this is for a maximum power output, not a sustained and constant listening level, most fuses will not snap at the rated value's, especially the larger maxi fuses, wafer fuses or even breakers, they are designed with quite a high tolerance for over current draw in most applications. I 100amp breaker or fuse should suffice for most people, but I would err on the safe side and use something a little larger.
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Top Secret, I can tell you but then my wife will kill me.
Posted By: chan4202
Date Posted: January 03, 2004 at 6:47 PM
Now if I run two 4 gauge power wires, with 80 amp fuses, an then each to the respected amp, will I be fine? I read that the rockford fosgate amp pulls only 50 amps while playing music and 80 amps peak.. I dont plan on having the bass turned up very much, so my gain will be turned down. What would this cause to happen, would the amp just not perform, it wont hurt anything right?
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Chandler Martin
Posted By: Durwood
Date Posted: January 04, 2004 at 7:15 AM
chan4202 wrote:
Now if I run two 4 gauge power wires, with 80 amp fuses, an then each to the respected amp, will I be fine? I read that the rockford fosgate amp pulls only 50 amps while playing music and 80 amps peak.. I dont plan on having the bass turned up very much, so my gain will be turned down. What would this cause to happen, would the amp just not perform, it wont hurt anything right?
Are you talking about running two separate 4-gauge power wires all the way from the battery back to the subs? That's kind of overkill. Just run 4-gauge from the battery back to a distribution block, and then 4- or 8-gauge from the distribution block to the amps. Put a 150-amp fuse as near the battery as you can. If your amps don't have internal fuses, then put the recommended fuse sizes between the distribution block and the amps. If you do use 8-gauge coming out of the distribution block, put a fuse on the 8-gauge wire as close to the distribution block as you can. Scott Gardner
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