Just got an MTX amp to replace my 5 year old RF one.

The RF one got power to the unit just as of yesterday but wouldn't power my sub.

Well... today I have the amp. Simple connection so I thought. I had to crimp new split connectors to the 8ga power and ground wires and to the 14ga remote wire. Everything is attached fine and not changed from my previous working setup other than the crimps and the amp. The ground is short and attached to my rear seat buckle bolt with scraped paint. The power wire is going to the battery with a ring connector and fuse within 18in which is fine. The amp power led won't light up... I spent 5hrs today retaking apart everything, putting new connectors on, and can't figure it out.

I know one possibility might be the amp, the only other 3 things are the power wire, the ground, or remote. Would a weak crimp cause a problem? Any other things to look for? Is there a way to test the amp outside the car just to see if it can get power?

Thanks

 

A weak crimp wouldn't cause that, but a missed crimp could. Sounds like you know what you are doing though so I doubt thats it. How about the fuse on the power line? Or the fuse(s) in the amp?

If you are sure everything is good, I'd take the amp in to a stereo shop and have them bench test it for you. They can easily tell you if its the amp or your wiring. Most places will do it for free too.

 

Yup first thing I did was test the two fuses and they both appear to be a-ok. It's really bugging me because it's such a simple install. I definetely didn't miss any crimps, some didn't go as tight as I would like and I'd like a better power terminal on the battery but what I have there now worked before for 5 years.

I think tomorrow I will go to the car audio place I got the amp from and have them test it (hopefully for free), if it tests fine then I may just have to have them install it. I called them earlier to see what they charge for installing and it is $75/hr minimum 1hr ouch!! especially for something that is 99% done.

Thanks

 

$75!

yikes.

where in CT are you? I know a couple good places in Newtown that, last I checked, weren't that expensive, but did great work.

 

Your tellin me, outrageous, and the place is a tad bit ghetto if I say so myself.

I'm in Meriden (right in the middle).

Newtown is about 50minutes away, didn't know there was anything there. Lots of open space and big houses

 

i'd do what Beetroot said. get the amp tested and change all the fuses, even if they look ok.

 

ah, not worth the drive.

I think its newtown, 2 places right off exit 7 on the 84

 

Well I brought it in today and he said the amp tested out fine.

Went home, replaced the remaining crimps including on the battery terminal itself, pulled out the receiver and can't spot a thing, the remote line crimp behind the headunit seems to be fine. Very frustrating pulling the HU out though, cut my hand, and pulled a wire on the led for my alarm so another thing to get fixed.

Have an appt for saturday now for them to install it. Watch it be something else and it had better not be something stupid and simple that I could have done on my own in 10 minutes....!

 

even tho the fuses may look ok they arent. change them and see 5 bucks for fuses is better then 75 for install

 

Sounds cheaper to buy a voltmeter.

Allows you to measure DC voltage on the power wire and the turn on wire, the quality of the ground, and the resistenace across the speaker wires.

 

Well the thing is with that is today I did the ol' lightbulb test.

Test 1:
The power and ground to the lightbulb = Lights up the bulb

Test 2:
Ground and remote line to the lightbulb = Lights up the bulb.

So it appears that everything has power going to the end, which if a fuse was blown I don't think would happen at all.

I just don't understand if everything has power to the amp wire end then shouldn't the amp power led at least light up?

 

Not sure how to edit messages here....

Anyways yeah I thought about the voltmeter, looking to see if my uncle has one. I know with the lightbulb that it is at least getting power, I would just like to know if it is as least 12v and if the ground is poor.

Would a power wire putting out less than 12v still power on the amp with reduced power or would it not power on at all?

 

a better question would be what voltage will your bulb light up down to?

Every amp shuts down with too little voltage. The exact point varies.

Most amps shut down with shorts across the speaker terminals too.

 

I just got a volt meter from work Will be testing at lunch both on the wires, grounds, and at the contact points on the amp itself. Hopefully the problem will become blatantly obvious.

 

Well just tested with a voltmeter. Getting 12v at the amp side of the terminal from the power and ground wires and around 11.6v im estimating from the remote and ground. Not sure if the remote has anything less than 12v then it won't work...

 

That remote probably is OK... but with only 12V I would suspect your ground of being poor. That should show ALMOST the same voltage as your battery, which should rest in the 13's when the car's not running.

You should re-test that with the car running and see if it goes up. How old is your battery? Just wondering...

Now disconnect one pair of speaker wires at a time, set the meter to resistance, and see what the speaker wires measure. You should see above 2 or 3 ohms. If you see below 1 ohm you have a shorted speaker wire or shorted speaker.

 

Ok brought the volt meter home to test with the amp in.

The meter tests around 13V on the battery when the car is off, nearly 14V when the car is on. The battery is new and put in about 3 months ago.

The power and ground together test around 12V when the car is off and around 13V when the car is running. The remote line tests a little under 12V or almost at it when the car is both off and on.

I think I located the problem though today at home. The power and ground remember test at 12V-13V at the end connectors. Well as soon as I connect them to the amp and turn the unit on the power tests at 5V when the car is off and around 6V when the car is on. The remote still tests around 11-12V when the car is both off and on. So it seems the ground is ok, the remote is ok (if it doesn't need more than 11.5V average). It seems that somehow 7V is being lost in around 1inch of space or so at the amp itself. I can't figure out why as the connection is fine to the amp (screw down plate where the split connector goes). There is really nothing else you can do to it. The only thing I can think of is maybe the terminal is a little too large and not contacting the screw like it should but I have moved it several times.

My other old amp had a straight in wire connection so that is why I am assuming that worked fine as you are shoving the wire directly into the unit. In this case you have the added piece in the terminals and the screws at the amp to cause an extra problem. So I know what the problem is but can't figure it out. I am probably just going to give up and see what the "pros" can do with it. I hate not being able to figure things out...