Wiring in a Stereo Amplifier...??

[MDF99]

Howdy, I need to a get a power wire out of the fuse box that's on only when the ignition is on. How do I go about doing this? This wire will let the amp know that the radio is on. The actual power for the amp comes directly from the battery. Do I just stick a wire onto one of the fuse blades or remove the fuse box and attach it to the back? I was thinking of hooking into the power window fuse. Thanks

 

[EMDDIESEL]

I would just pull a fuse and stick the wire behind the fuse blade. You wont hurt anything by doing it this way, and if there is ever a problem, its easy to disconnect. ALthough, if you want to be super neat about things, you could take the whole fuse box out and run a wire behind it. As for the power window fuse, thats a good choice, you could also use the wiper fuse.

 

[mikel]

Take alook at the wiring diagram for the radio in your truck. My factory radio has a switched 12v lead that I used to activate my alpine amp when I installed it. The amp does not need to be switched anywhere else. It gets a ground and a full time positive 12v connection and then a small low current activation signal that the radio can provide. Wired this way the amp only runs when the radio is on.



hope this helps,

Mike



Edited to clarify that I am using the FACTORY RADIO and not an aftermarket radio.

 

[SLang]

Use the power antennae on your head unit. If it is an aftermarket that's the blue wire. This will reduce turn on / turn off tump produced from the amp being on. If you use ing. the amp may be on and the radio off. Turn on tump will damage speakers!

 

[Cooker]

You could also draw wire from any 12v ignigition (so you don't accidentially leave the amp on when you turn the truck off) source and put a switch on it. That way you can turn the amp off, if you wish, while still listening to the rest of the stero.



If you use the power windo circuit the amp won't work when the key is in accessory.



Are you running the factory head unit? If not there are almost always power antenna or remote turn on leads on the back of aftermarket head units.



-Ryan

 

[MDF99]

It's the stock radio, premium sound system (6 infinity speakers... 2 in each door, 1 on each side behind seat). I used a line signal converter wired into each of the rear speakers to get the music signal for the amp via the RCA plugs. I hooked the accesory wire into the windshield wiper fuse, it works great! It's true that the amp is always on now whenever the ignition is on, but I always have the radio on when i'm in the truck anyhow so no problem. The amp works when I turn the key back to accessory as well, like the wipers do. The new speakers little 6" subwoofers mounted tubes that I strapped onto the big tray behind each seat. I still have storage underneath the tubes. The amp is 75watts x 2.

 

[SLang]

Another thing I forgot to mention, hook the power wire up to the drive side battety. I do not know why but if you hook it up to the secondary battery (passenger side or one with out ing. on it) it will kill it. I'm a EE and don't know how that happens, but I killed a couple in my Chevy before switching over to dual alternators and seperate power systems.

 

[Cooker]

SLang,

I'm hung up on this drivers side battery thing? The batteries are run in parallel and it should be fine to do, unless the two batteries are different ages, sizes, or are different batteries all together. Hmmm...



-Ryan

 

[EMDDIESEL]

My friend has his Amp power cable coming from the passenger side battery for 2 years now with no problem. What problem did you have?

 

[SLang]

It may be a distance thing. I had a spare battery in the bed of my Chevy.



At first I ran 1 alternator and 2 batteries. If I played the stereo hard (about 140-150A on the line side) the second battery would go dead. I had a 170-180A alternator so power supply is not the problem. This battery was killed in about 6 months. I changed to a D-8 dozer battery for the rear hoping the 225+ minutes of reserve would cure the problem. The battery would have the same problem. After 5-6 passes at compatition with the engine running I would have to let the truck sit on a charger to regian full stregnth. I put an ammeter on the line going to my amps. During comp. it would pull 160+A and when sitting and charging with stereo off it would pull 5-6A until charged and then pull <1A.



Got pissed and put a second alternator on and ran a seperate power system for the steroe. Upgraded to 3 D-8 bateries and called it quits. No charging problem.



Now as far as the 1 alt. and 2 batt. problem. I can not figure it out. Could have been differance in batteries. Or the voltage drop across 14 ft. 1/0 power cable. Or the amps just sucked on the rear batt. so much the resistance went high. I'm not sure and I'm an electrical engineer.



When I seen the dual bat. with out an isolator in our cummins I figured they got away with it by using the drive side as a primary and pass. side as a secondary bat. That is why everything (charging and load) is hooked to the driver side. That is why I suggested and going with my experience to use the drive side only. Logic says its all one node, but does it actually act as one node?



Edit- Just for completeness I was Running 3000+ Watts, 4 orion 12's, 14 high end speakers, 2 180 amp alternators, 3 D-8 (dozer) batteries, dual 1/0 runs from second alternator, and 4. 0 farad of caps.

 

[Turbo Thom]

For a power lead call Genos and get you a Painless Wiring 7 circuit system. 3 constant hot and 4 ingnition hot. I put one on my truck and it really is the trick. I mounted it on the fender well and ran the wires through a piece of clear tubing through the fire wall. Having a wire for all needs is nice and convenent'.

Preston