MTX amp blowing
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=78857
Printed Date: April 29, 2024 at 1:30 AM
Topic: MTX amp blowing
Posted By: surendrant
Subject: MTX amp blowing
Date Posted: June 07, 2006 at 11:41 PM
I installed an old MTX amp in a 2003 honda civic. I don't know the model number but it 500 watts RMS @ 2 ohms. Its a being used to run a 10" MTX Thunder sub i believe its about 400 watts RMS. I've done a lot of amp installs so i'm 100% sure the problem isn't in the wiring. The remote wire is ok, and the 12+ wire is ok , and the ground seems to be good too, it's grounded to the chassis and the paint has been scraped off. But when i hooked up this amp with the gain at zero, the amp started smoking. I opened up the amp and a few resistors are burnt to a crisp. I have no clue why this would happen and just my luck, my multimeter is broken. Any ideas?
Replies:
Posted By: pmh61
Date Posted: June 08, 2006 at 12:02 AM
what size of fuses are in it and if there is not any in the amp how big of an inline fuse are you using from the battery? start there i guess
Posted By: aznboi3644
Date Posted: June 08, 2006 at 12:14 AM
Check if the power and ground and remote wires are touching where connected at the amp.
Posted By: aceracer24
Date Posted: June 08, 2006 at 12:50 AM
Not sure how old is old but i now there is a low/high input on mine that says if you have it for low input and you use high input wiring you'll damage the speakers. Low input would be RCA cables and high input would be wired from the deck. DOn't ask me why high would be wired from deck...I always thought RCA at 5v was high but according to the manual for the amp, thats considered low /shrug worth a check anyway.
-------------
1968 VW Beetle
Pioneed DEH-780MP, 2 10' Memphis PR104D, Memphis PR500.1, TXC 6.1, MTX Thunder 8502
Posted By: surendrant
Date Posted: June 09, 2006 at 3:34 AM
my ground is fine, none of the wires are touching. the amp has 3 25 amp fuses and the 10 guage kit i'm using has a 60 amp fuse. Even if the amp wasn't gettin enough current i'm pretty sure it would just overheat not smoke cuz i didn't even turn up the gain or the deck volume. I'm thinking its a problem with the RCA's from the deck, its used and i don't know its history. Its a pioneer P4700 MP. Any ideas?
Posted By: aznboi3644
Date Posted: June 09, 2006 at 7:48 AM
WHOA WHOA WHOA HOLD UP!!!
Your amp is fused at 75 amps and you have 10 GUAGE POWER WIRE. This could possibly be the culprit. Dude 10 gauge is like for a 200 watt max amp. You should ATLEAST get a 4 gauge kit. Even if your inline fuse is a 60 amp fuse that 10 guage wire cannot supply the amount of current your amp may pull.
500 RMS is WWWAAAYYY too big for a little 10 gauge kit.
GET A BIGGER KIT!!!! ATLEAST 4 GAUGE!!!!
No one here thought this could be the problem because MOST people would not even think that you have a dinky 10 guage power wire.
Posted By: DYohn
Date Posted: June 09, 2006 at 8:34 AM
Your power wire size will not cause the amp to fry. Using too small wire guage will cause the wire to fry (and maybe your car, too.) Either the amp is defective, or it has been severely overloaded. In any case remove it from your vehicle and get it repaired. ------------- Support the12volt.com
Posted By: Velocity Motors
Date Posted: June 09, 2006 at 9:23 AM
Sounds like you reverse the (+) & (-) wire to me. Not implying that your not capable of installing an amp properly, but if an amp starts smoking when the gain is set to 0 when it's turned on, then there's a dead short somewhere and if the fuse didn't blow at the battery or at the amplifier, then this could be the culprit.
-------------
Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA
Posted By: surendrant
Date Posted: June 09, 2006 at 1:52 PM
lol, i checked that one too, the wires are going to the correct terminals. The weird thing is before this amp i tried a 300 watt rms amp and it would just keep blowing its fuse and the power light would continuosly stay on even when i removed the remote wire. The light would only go off when i removed the power wire or the rca wires. So i decided to try another amp and this is what happened. Also when i ran the power wire the inline fuse was blowing cuz there were some cuts in the wire that happened when i was putting everythin back but i solved that problem taped up all the exposed spots. I'm starting to think this is a problem with the deck maybe its giving an extreemly high rca out for some reason?
Posted By: ferretvw
Date Posted: June 09, 2006 at 2:37 PM
have you tried a different set of RCA's? It is possible you could get the amp into protection that route.....
Posted By: DYohn
Date Posted: June 09, 2006 at 2:57 PM
surendrant wrote:
lol, i checked that one too, the wires are going to the correct terminals. The weird thing is before this amp i tried a 300 watt rms amp and it would just keep blowing its fuse and the power light would continuosly stay on even when i removed the remote wire. The light would only go off when i removed the power wire or the rca wires. So i decided to try another amp and this is what happened. Also when i ran the power wire the inline fuse was blowing cuz there were some cuts in the wire that happened when i was putting everythin back but i solved that problem taped up all the exposed spots. I'm starting to think this is a problem with the deck maybe its giving an extreemly high rca out for some reason?
Sounds to me like ripping out everything and starting over is in order... and doing it RIGHT this time. ------------- Support the12volt.com
Posted By: surendrant
Date Posted: June 09, 2006 at 4:07 PM
 i was thinking of that too. But even if there was another cut in the wire somewhere it wouldn't cause the amp to smoke cuz its all fused. Unless maybe there is a cut in the RCA wire?
Posted By: aceracer24
Date Posted: June 09, 2006 at 4:24 PM
aceracer24 wrote:
Not sure how old is old but i now there is a low/high input on mine that says if you have it for low input and you use high input wiring you'll damage the speakers or amp. Low input would be RCA cables and high input would be wired from the deck. DOn't ask me why high would be wired from deck...I always thought RCA at 5v was high but according to the manual for the amp, thats considered low /shrug worth a check anyway.
Feature Setup and Adjustments
1. Selecting the Input Sensitivity Range – Before you turn on your system, you must select the proper input
sensitivity range on your amp using the button labeled INPUT SENS located in the GAIN CONTROL section of
the control panel.
• Setting for Aftermarket Source Units: Refer to your aftermarket owner’s manual for line level output
specifi cation. If the specifi cation is not available, please follow the instructions listed below.
X1 POSITION: 100mV–1V (Typically for RCA Input)
• Setting for Factory (OEM) Source Units: To check the amount of voltage that is present from the source
unit, take a multi meter, or a volt/ohm meter, on the AC setting, (range from 100mV up to 10 volts) attach the
positive and negative leads directly to any exposed speaker. It will not matter if the polarity is correct, it will
read the same amount of voltage.
X10 POSITION: 1V–10V (Typically for Speaker Level Input)
Note: It is important not to have the amp set up to receive a low voltage signal and give it a high voltage signal. Doing this can cause damage to the amp.
I'll repost this again. It's very important on the MTX amp. I've never heard of this on any other type of amp but who knows. If your running RCA and have it set to the high input setting on the amp (assuming yours has one) you could damage the amp or speakers. Other then that,I don't know. Check to see if your amp has this low/high input and make sure yours is set right.
------------- 1968 VW Beetle
Pioneed DEH-780MP, 2 10' Memphis PR104D, Memphis PR500.1, TXC 6.1, MTX Thunder 8502
Posted By: geepherder
Date Posted: June 09, 2006 at 7:48 PM
So if you remove the amp turn on and the amp stays on, that means there's an internal short inside the amp. Also, unplugging the rca's should have nothing to do with the amp staying powered up, unless it's only grounded through the rca shields. Your amp is toast. You can send it for repair, or buy another. ------------- My ex once told me I have a perfect face for radio.
Posted By: aceracer24
Date Posted: June 10, 2006 at 12:44 AM
Just a quick note, again I am not sure when MTX put this feature into their amps but, on the newer ones you don't have to run a remote power wire if:
• Smart-Engage™ Auto-Turn-On - An auto-turn-on circuit is included within the amplifier. A remote turn-on
wire is not necessary when connecting the amplifier’s high-level input to a high-powered source unit (car
stereo). The amplifier will automatically turn on when music is received through this type of connection.
Note: Smart Engage™ is only active on the left input.
I am still trying to figure this out myself though....
-------------
1968 VW Beetle
Pioneed DEH-780MP, 2 10' Memphis PR104D, Memphis PR500.1, TXC 6.1, MTX Thunder 8502
Posted By: surendrant
Date Posted: June 10, 2006 at 7:24 AM
thanx guyz i'll definately check that out. I jus wanna rule out the head unit as the possible cause of the problem before i blow the amp. You guyz think it could be a problem from the head unit?
Posted By: aceracer24
Date Posted: June 10, 2006 at 10:21 AM
I personally do not think so but I'm no expert /shrug
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1968 VW Beetle
Pioneed DEH-780MP, 2 10' Memphis PR104D, Memphis PR500.1, TXC 6.1, MTX Thunder 8502
Posted By: geepherder
Date Posted: June 10, 2006 at 10:23 PM
While the possibility exists that you have a problem with your deck as well, we cannot rule out the fact that your amp has a problem. Smoking is never a sign of a healthy amp. If you disconnect all wiring from the amp, and test it directly from the battery with a fused power, and a ground lead, does it come on without anything connected to the remote on terminal? If so, your amp is bad.
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My ex once told me I have a perfect face for radio.
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