Faulty amp? No speaker output voltage

Willydk · Feb 25, 2015

Hey guys, so in my last thread http://www.caraudio.com/forums/wiring-electrical-installation-help/614091-how-test-if-line-out-works-everything-seems-fine-but-speakers-doesnt-work.html

adulbrich and keep_hope_alive helped me to get things moving, and by now, I think i might know where the problem is.

I have this weird Terminator GX-5002 500W amp, it powers up, but the sound of my sub-woofer is really quiet.

I measured speaker output voltage and there's nothing

I'm not sure if i'm measuring it in a wrong way(again), but it's really weird, because there is some sound, but it's very quiet. ( I played with filters as-well, i can only make it more quiet)

+ I can only get some sound when I connect only one RCA plug.

(Found reason for that - I messed up my Line output converter wiring) - Could that cause the other problems? EDIT: Okay, tried using RCAs and 2.5 plug to my phone - same thing - plays as loud as it was played directly from the phone

I guess the only thing that I can still test is connect another speaker? //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif I'll start looking for a new amp already

I did a little test to see if amp does anything at all - I've connected speaker wires to RCA lead and the volume was exactly the same.

Then i connected(just for a blink) speaker wires to power cords - to see if it's subwoofers problem- the noise it made was much loud. + I tested the subwoofer at home using home amp.

My amp is cooked? :/

Jepalan · Feb 25, 2015

Sounds like amp might be fried.

I read your other thread and did not see this asked:

Where is your LEVEL dial set?

Where is your LPF dial set?

Where is the X-Over switch set?

Where is the HPF dial set?

How do you have the sub wired to the amp? i.e. which amp terminals exactly?

You should be wiring the sub only to the two terminals marked "BRIDGED" in this picture...

Jepalan · Feb 25, 2015

Also...

Did you check DC volts at between amp power & ground terminals? what does it read?

If you disconnect the sub completely and set DMM to read ohms, what reading do you get between the two sub wires?

Willydk · Feb 26, 2015

Also...Did you check DC volts at between amp power & ground terminals? what does it read?

If you disconnect the sub completely and set DMM to read ohms, what reading do you get between the two sub wires?

Well when I got it powered up, and my RCAs done I started experimenting. Different settings, channels etc. I tried bridged connection, as well as left and right channel. I will take some pictures tomorrow of settings I tried, voltages and installation. Also I will take my amp home, and I will try to power it using car battery charger, random speaker and my phone RCA.

DC volts at between amp power & ground terminals - I think it was 24V ( I tried it, and I was suprised, because i thought it had to be ~12, turns out it was wrong DMM setting, switched to the other one and it was ~12 when the engine is off)

Weird thing happened today:

I went to check out one second-hand amp. We hooked it up on my car, and the the screen (fancy amp) showed that there's no input comming in. We tried rcas from my phone - same thing.

But it's quite fishy, because the guy who's selling it said he got it from his friend because it was faulty, and he fixed it. He just texted me that he connected it at home and it worked.

Willydk · Feb 27, 2015

Well I'm totally lost.

I brought my amp back home, and tested it using car charger, phone RCAs and a speaker. IT WORKED

That means there's a problem in my wiring. I will try to describe how I wired everything.

(picture isn't mine, just to show where I connect them

)

Positive wire - directly on car's battery positive terminal.

Negative wire - on the bolt where battery's negative wire is wired.

Remote wire - there's no remote wire on my radio, so I just stripped tail light and wired it on the bulb wire that lights up when ignition is on.

I remember there's something to do with cable thickness. For my power wires I'm using same thickness wires for both positive and negative, I bought them in car audio store, they are not super thick like the ones people use for insane setups, but they are decent. Could it be the ground wire? Both positive and ground are ~1 meter long, same thickness.

EDIT: Read a little bit about cable thickness - should be fine.

I'm loosing my hope. I tried re-connecting everything again in the car + I changed my amp-sub wire.

Still nothing ;(

+ extra plot twist: I was playing with my head unit settings, and I found out, that if I try to balance speakers all the way to the front - nothing is playing, so I'm guessing that both front and rear speakers are on rear output.

so IF i connected my Line output converter to the wrong wires, that would explain stuff. But now when I wrote this, I remembered that I tried using RCAs straight from my phone, that worked fine when I tested the subwoofer seperately.

This is a HUGE headache.

I am guessing this is the most stupid and complicated troubleshooting on the forums //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

Jepalan · Feb 27, 2015

Well I'm totally lost.
I brought my amp back home, and tested it using car charger, phone RCAs and a speaker. IT WORKED

That means there's a problem in my wiring. I will try to describe how I wired everything.

(picture isn't mine, just to show where I connect them

)

Positive wire - directly on car's battery positive terminal.

Negative wire - on the bolt where battery's negative wire is wired.

Remote wire - there's no remote wire on my radio, so I just stripped tail light and wired it on the bulb wire that lights up when ignition is on.

I remember there's something to do with cable thickness. For my power wires I'm using same thickness wires for both positive and negative, I bought them in car audio store, they are not super thick like the ones people use for insane setups, but they are decent. Could it be the ground wire? Both positive and ground are ~1 meter long, same thickness.

EDIT: Read a little bit about cable thickness - should be fine.

I'm loosing my hope. I tried re-connecting everything again in the car + I changed my amp-sub wire.

Still nothing ;(

+ extra plot twist: I was playing with my head unit settings, and I found out, that if I try to balance speakers all the way to the front - nothing is playing, so I'm guessing that both front and rear speakers are on rear output.

so IF i connected my Line output converter to the wrong wires, that would explain stuff. But now when I wrote this, I remembered that I tried using RCAs straight from my phone, that worked fine when I tested the subwoofer seperately.

This is a HUGE headache.

I am guessing this is the most stupid and complicated troubleshooting on the forums //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

Keep going! You have actually made some good progress. Start by carefully re-wiring your LOC. Double check that you have the correct wiring assignments for your HU and double check the LOC instructions and just re-wire it. Based on what you described, it sounds like something is still messed up there.

Good luck.

keep_hope_alive · Feb 27, 2015

i agree, i think the issue is in your signal cabling.

good job testing external from the car.

at this point, every connection is suspect.

Willydk · Feb 28, 2015

Keep going! You have actually made some good progress. Start by carefully re-wiring your LOC. Double check that you have the correct wiring assignments for your HU and double check the LOC instructions and just re-wire it. Based on what you described, it sounds like something is still messed up there.
Good luck.

i agree, i think the issue is in your signal cabling.
good job testing external from the car.

at this point, every connection is suspect.

Thanks guys. Well I thought there must be something with power wires, so I changed the positions. For ground I used bolt on car chasis in upper trunk part(I saw youtube video where a guy used that place) carefully sanded the area before connecting. Positive wire was close to the main clamp, on a smaller screw, I moved it directly on the clamp. Well It doesn't really make sense, but what the hell, my whole problem doesn't make any sense. But that did not help. I didn't have my phone rca cable in the garage, so I will try that tomorrow. HOPEFULLY, now it's only LOC problem.

Willydk · Mar 1, 2015

Okay, I narrowed it down to power cables.

I tested my amp in the car using phone RCAs. It actually plays a lot louder if I just touch speak wires to phones RCA than through my amp... //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

I'm using around 1 meter of

this cable for ground and positive.

According to crutchfield table it should be okay, but what's left? I changed wiring spots, AMP does get power and ground, but amp does not output stronger signal for the speaker.

Should I buy thicker cables? :/

Jepalan · Mar 8, 2015

Okay, I narrowed it down to power cables.
I tested my amp in the car using phone RCAs. It actually plays a lot louder if I just touch speak wires to phones RCA than through my amp... //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

I'm using around 1 meter of

this cable for ground and positive.

According to crutchfield table it should be okay, but what's left? I changed wiring spots, AMP does get power and ground, but amp does not output stronger signal for the speaker.

Should I buy thicker cables? :/

Do you have at least +12v on the Amp's REM input terminal? Can you measure the DC Volts directly between the amp ground terminal and the amp B+ terminal and between the amp ground terminal and REM terminal? Is the amp even turning on?

Willydk · Mar 9, 2015

Do you have at least +12v on the Amp's REM input terminal? Can you measure the DC Volts directly between the amp ground terminal and the amp B+ terminal and between the amp ground terminal and REM terminal? Is the amp even turning on?

I don't have 12v on my REM terminal, it has ~5.6V (took it from tail light bulb, that is on whenever ignition is on). And B+ is 12.3V when engine is off. Amp does turn on ;(

Jepalan · Mar 9, 2015

I don't have 12v on my REM terminal, it has ~5.6V (took it from tail light bulb, that is on whenever ignition is on). And B+ is 12.3V when engine is off. Amp does turn on ;(

5.6v on REM is not right. Try temporarily connecting a wire from the amp B+ to the REM and see if it turns on and plays. I bet the amp isn't fully turning on with only 5.6v on the REM input.

Willydk · Mar 9, 2015

5.6v on REM is not right. Try temporarily connecting a wire from the amp B+ to the REM and see if it turns on and plays. I bet the amp isn't fully turning on with only 5.6v on the REM input.

It worked... THANK YOU, I am amazed, and I had no clue that Remote wire requires 12v

I thought it only needs very little voltage.

dubstepper1000 · Mar 9, 2015

Well when I got it powered up, and my RCAs done I started experimenting. Different settings, channels etc. I tried bridged connection, as well as left and right channel. I will take some pictures tomorrow of settings I tried, voltages and installation. Also I will take my amp home, and I will try to power it using car battery charger, random speaker and my phone RCA.
DC volts at between amp power & ground terminals - I think it was 24V ( I tried it, and I was suprised, because i thought it had to be ~12, turns out it was wrong DMM setting, switched to the other one and it was ~12 when the engine is off)

Weird thing happened today:

I went to check out one second-hand amp. We hooked it up on my car, and the the screen (fancy amp) showed that there's no input coming in. We tried rcas from my phone - same thing.

But it's quite fishy, because the guy who's selling it said he got it from his friend because it was faulty, and he fixed it. He just texted me that he connected it at home and it worked.

I had a similar problem a few weeks ago, the problem turned out to be in the fuse holder, I was reading 12V but no signal from speaker terminals. There was a faulty connection in the fuse holder that caused the voltage to drop below 12V when the amp called for any power. Did some research and found that my amp can function properly at 10V but it wont supply power to the terminals and the protect light will not light up even though it is receiving insufficient voltage. Double check all your connections from your battery all the way to the amp (including fuse holder) and watch for corroding on the wires and terminals, re-strip them if needed. If you want to make sure you are getting a signal from your RCA's, attach a DMM set to 0-2V AC to one of them (+ on center post, - on outer shell). You should get some signal when you play test-tone/music if it is good.

Jepalan · Mar 9, 2015

It worked... THANK YOU, I am amazed, and I had no clue that Remote wire requires 12v I thought it only needs very little voltage.

Most excellent! Glad you found it. Now you need to come up with a different scheme for your REM turn on source. Yes - it needs to be a full 12v for some amps (most?).

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