sound system

[farmer]

hey I just put a cheapo walmart radio in my truck and wired up an amp and subwoofer i got for free. i have power to them amp but i think the blue wire from the radio is shorting, the amp wont come on. what is that supposed to have for power going through it? could i just run a toggle switch on an ign on circuit to the amp? I'm new to this audio stuff and I'm on a tiny budget

 

[ZackW]

It only requires like 0.3 amps or something like that, but I have wired the remote to a direct 12v (usually fusebox) source before without issue. Just find something in your fusebox that only comes on with the ignition and stick the wire in there, that way you don't have to wire a switch and the amp only comes on with the car.

also, radios generally have 2 blue wires on them, the other is for a power antenna, and usually doesn't have enough power to kick on an amp. So make sure you didn't use the wrong one first.

 

[farmer]

ok so i could just splice it into the ignition hot wire going into my radio? should i run a fuse in the blue wire too or not worry about it? and yeah I will double check to make sure i got the right blue wire

 

[baxtej44]

ok so i could just splice it into the ignition hot wire going into my radio? should i run a fuse in the blue wire too or not worry about it? and yeah I will double check to make sure i got the right blue wire

i would run a fuse, can never be too safe. gl

 

[ForOffRoadDriving]

your cheapo walmart radio should have a remote wire in the harness supplied with the radio, i would just hook it up to that wire since thats what its there for. unless theres something wrong with the radio and its not putting power out of the remote wire when its turned on, have you used a DVOM to check the electrical status of the wire?

 

[farmer]

yeah i checked the wire and its grounding out, so theres yer problem! i'll just run an ignition hot only wire to the amp

 

[farmer]

amps toast. theres power going into the blue wire at the amp, the power wire, and still no light, no sound

 

[ForOffRoadDriving]

2 other simple things to check since i didnt see them mentioned, check the fuse on the amp and make sure youre ground to the amp has good contact to the chassis and little to no resistance between the amps ground terminal and the chassis grounding point (use a voltmeter on the Ohms setting to check this)

 

[farmer]

yeah all my fuses are good. I'll double check that ground though...i kinda half assed it, it was late and my ground cable is wicked short. my setup right now is an unknown jensen-in-a-box (like the kenwood in your thread) with a Jensen amp that I found NO info on the internet screwed to the side of it and it sits behind the driver seat, where would be a good spot to ground it? and another dumb question while I'm here. i used 6 ga. wire and it doesn't really fit well into the amp, whats a good way around that?

 

[ZackW]

Those Jensens are generally fairly underpowered amps that most of the time only require maybe a 8ga wire ran to them. Hell, depending on the size of the amp, I used to run a lot of cheap jensens off nothing more than 10-12ga power/ground wire just fine.

Definitely check your ground though. I used a seat bolt for mine, and the amp would kick off completely for no reason. I couldn't figure it out as everything was tight and connected properly. I only just happened to notice a spark out of the corner of my eye that told me the ground wasn't getting a good connection. Moved it to the seatbelt bolt and had no problems since.

 

[farmer]

I'm using a jump seat bolt now, is the seatbelt bolt closer to ground? or is it just cleaner contact area? and the only reason for the overkill wire is it came in a kit from walmart, $35 how can you go wrong? lol

 

[farmer]

ok nothing worked... is there a way i can bench test the amp and take out all of the stupid variables in the truck before i toss it?

 

[RangerFabWorks]

if your sure the amp is getting power from the battery, run a jumper wire from that to the signal location, and see if the amp lights up. if it doesnt, and you have a good ground, toss it.

 

[ForOffRoadDriving]

you can also use a spare car battery and test it, just get 3 test leads (wire with alligator clips on both ends) and put pos to power on amp, neg to ground on the amp, then take the 3rd wire and clip it to battery positive and then touch it to the remote on the amp and see if it lights. by doing this you verify that good ground is present, batt voltage is good (if at or above 12.6v) and that your remote wire connection is good. one of my MTX amps had a burned out LED, so it never came on until i unsoldered it from the circuit board and intalled a new one from radioshack, now it works like a charm!

 

[farmer]

ok so i found the problem, someone had taken the amp apart before and didnt hook up the control panel, 5 minutes later, i have subwoofer
now the question is, can i run the subwoofer bridged off 2 channels, and my 4 cab speakers off the other 2 channels? its a 400 watt amp. or should I find a 2 channel for the amp and run the speaker off the 4 channel?