Amp not working, amp or wiring?

[j2000]

Hello. I have a basic system, front speakers and sub connected to my amp, and rear speakers connected to radio. I had the amp installed by a shop, and it worked fine, but only for a month. After that, the amp started going into protect mode. I am unwilling to go back to the shop, as I now question their reliability. I looked around on the internet, and emailed the amp manufacturer and they said they think it's a problem with the amp. I sent them the amp, and they sent it back ("repaired"), and it still didn't work. I don't know at this point if it is the amp, or the wiring that is the problem. I have a new amp to use, but I am now afraid to plug it into the wiring, since I'm not sure if that is the problem. I have inspected the wires, and don't see any obvious problems, but I am by no means an electrician.

What is the proper way to test the wires to make sure they work? Can I test them without plugging the amp in? Thank you.

Click to read more...

 

[wew lad 5,000+ posts]

What amp is it? Your wiring is likely fine, if you inspect the wiring along the entire length and see no obvious cuts or points where the wire is crushed then your wiring is probably ok.

However, you may be starving the amp to death causing it to overheat and protect if your amp is pulling more current than your car can provide. You could also be driving the amp with too low of an impedance, make sure your sub is not wired to a lower ohm load than the amp is rated to handle. Another option is the gain set too high on your amplifier, make sure you don't turn the gain up to max because it's "louder." Match the gain with your headunit preouts.

 

[wew lad 5,000+ posts]

the ca.com server decided to go slow as hell and double post - disregard this..

 

[j2000]

Thanks for the response. It is a PPI P900.4. The gain definitely wasn't up too high, but it is certainly possible that the amp isn't getting enough power. Do you know how to check this? I have a multimeter, but I am not totally sure how to use it. I have also heard that you aren't supposed to test wiring when it isn't active. I appreciate any help.

 

[wew lad 5,000+ posts]

If you're using 4 gauge copper from the battery to the amp then your amp should be getting plenty of power, PPI900.4's can use about 100 amps of current peak, although i doubt you're pulling any more than 60 or so. Put your multimeter on voltage DC and probe the positive and negative before you turn up your music and after, if the voltage you read is lower than 12 at any time you're pulling too much current out of your car or theres a spot of extreme resistance along your power wire.

you need to look into how you have your subs wired. the amp cannot handle a 1 ohm load. If you have your sub wired to 1 ohm the amp will overheat or protect.

 

[j2000]

It is 4 gauge OFC. I will try the multimeter when I do get it hooked back up. Also, the amp is 4 ohm and I'm bridging it on the 2 rear channels, I'm confident that had nothing to do with it. Thanks for the help!

 

[hispls 5,000+ posts]

If you're unsure of things, use a very small fuse on the amp's power wire, (3A or 5A) for low power testing. This way if something is wrong you won't be able to do any damage to something. You can get a fuse holder at any parts store or radio shack for about 3.50$

 

[seedlings]

Can you take a pic of the amp's chassis ground connection?

CHAD

 

[j2000]

I will try this, thank you!

What should be my actual process in hooking the amp up? I have the fuse in the power wire removed now. Is it okay if I hook the amp wires up, then install the fuse in the power wire, and start the car up? What is the likelihood of damage happening do it this way? If my amp is getting UNDERpowered, how long will it take for that to do damage?

 

[j2000]

So I tried hooking it up today. I used 5a fuses on the amp, and I used a multimeter to make sure its getting the right voltage. It said it was getting 12.7, so I tried turning it on. When it came on, it was in protect mode. There was nothing hooked up but the power, ground, and remote. I immediately turned it back off when the protect mode light came on. Any ideas as to what it could be? Also, now that it has been in protect mode, will it come out of protect? Any helpful info is appreciated!

 

[wew lad 5,000+ posts]

did you check the internal fusing for the amp?

it sounds like a faulty amplifier to me

 

[j2000]

I did not. However, I am almost certain it isn't the amp. I've had these problems for a while, so I contacted the manufacturer of my amp. They said to send it in, and I did. I ended up getting a new amp, and it still isn't working. So, I'm sure that isn't the issue.

 

[speedyjuarez Premium Member]

are you sure you have the subs wired correctly to the amp?

what are your gains etc set to?

Try running the amp with no speakers or sub connected, only have power, ground, remote and rcas. turn up the volume and see what happens, then connect one speaker at a time.

 

[wew lad 5,000+ posts]

If you connected the amp with power gnd and remote properly and those were the only wires connected and itvstill protects then its a bad amp. there's nothing else it could be besides a low/high voltage input , bad internal fuses, or incorrect polarity at the inputs.