no sound from amp
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=128819
Printed Date: April 29, 2024 at 7:05 AM
Topic: no sound from amp
Posted By: jgonzales82
Subject: no sound from amp
Date Posted: October 12, 2011 at 1:09 PM
Okay i have a mtx 8302amp that i had pushing 2 jl audio 12's (model w0v2). Those bumped very good in my car. I then got a mtx 8500 from a friend hooked it up to the mtx amp turned on but no sound. so i swapped out the rca cables and checked the remote wire to see if they got pinched anywhere and still nothing still nothing! so now i picked up a eclipse cd5442 to see if the rcas went out on my alpine and i still have no sound with the eclipse.
so now im thinking my amp has bad connectors so we test the amp and sub in a friends ride and they both work and just for fun we hooked up the eclipe deck and it worked with everything also.
Replies:
Posted By: haemphyst
Date Posted: October 12, 2011 at 1:47 PM
jgonzales82 wrote:
I then got a mtx 8500 from a friend hooked it up to the mtx amp turned on but no sound.
You hooked an amp to an amp...? Help *me* out (probably everybody else, too...). What, precisely did you do? ------------- It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: i am an idiot
Date Posted: October 12, 2011 at 1:57 PM
If the gain controls are turned all the way counterclockwise, that amp will have no output.
Posted By: jgonzales82
Date Posted: October 12, 2011 at 3:59 PM
yeah i have the gain set half way! on the mtx 8302 if your bridging the amp you only use the left gain and turn the right side all the way down.
Posted By: jgonzales82
Date Posted: October 12, 2011 at 4:00 PM
mtx 8500 is a sub and i hooked up to my mtx 8302 amp!
Posted By: i am an idiot
Date Posted: October 12, 2011 at 5:28 PM
That is not how you use the gain if you are bridging that amp. Both channels need to be set at the same level, and you have to feed both RCA inputs.
Posted By: jgonzales82
Date Posted: October 12, 2011 at 5:33 PM
okay so i tried it with both gains all the way up and still nothing
Posted By: i am an idiot
Date Posted: October 12, 2011 at 8:06 PM
Single or Dual voice coil woofers? Have you used an ohm meter to verify that the woofers do not have an open voice coil?
Posted By: soundnsecurity
Date Posted: October 12, 2011 at 8:18 PM
check your main fuse. sometimes it can be only slightly blown, meaning it is blown but the end fell out in a way that it makes just enough contact to turn the light on the amp on but the amp wont output. you need to test the fuse because you might not be able to tell just by looking at it. test for voltage on each side of the fuse, if its semi blown you will notice a pretty big voltage drop.
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Posted By: jgonzales82
Date Posted: October 12, 2011 at 8:51 PM
they are dual voice coils!
Posted By: jgonzales82
Date Posted: October 12, 2011 at 8:53 PM
huh i never thought of that ill have to check tomorrow go to work! hopefully that'll be the problem
Posted By: jgonzales82
Date Posted: October 12, 2011 at 8:54 PM
jgonzales82 wrote:
huh i never thought of that ill have to check tomorrow when i get to work! hopefully that'll be the problem
Posted By: i am an idiot
Date Posted: October 12, 2011 at 9:24 PM
Are you sure you do not have the voice coils of the woofer wired out of phase?
Posted By: jgonzales82
Date Posted: October 13, 2011 at 11:54 PM
okay well i checked the fuse and it looked burnt and melted a little bit so i swapped it out with a new one but still got no sound! As far as the sub being wired outta phase i checked that and it is fine. i also got a chance to hook up a rockford fostgate amp up and that doesn't work either. I think im just going to buy a brand new install kit and see if that will work.
Posted By: soundnsecurity
Date Posted: October 14, 2011 at 12:03 PM
ok, you said you changed the fuse but did you check the voltage across the fuse and fuse holder? you said it looked burnt so there is a chance that your fuse holder could be bad and causing a bad connection. without testing for the proper voltage on both sides of the fuse holder there is really no way to know is it is or isnt the problem.
also it could be your RCA's, just because they arent pinched doesnt mean they are good. they could have been pulled and stretched to the point where the small wires inside are broken and its hard to tell just by looking at them. if you can before you buy a whole new amp kit just run a temporary rca from the radio to the amp just to make sure thats not your problem.
and check your ground for the amp, sometimes things come loose without realizing it during an install.
and i just thought of something, you did unhook the original JL 12's right? you didnt just add an mtx 8500 on top of the two 12's and hook it all up to the same amp, right? -------------
Posted By: jgonzales82
Date Posted: October 14, 2011 at 11:12 PM
yeah i swapped out the fuse holder with a new one and i checked the voltage and it was fine. yeah i took the jl's out and put the mtx in. also i think im going to just move my amp and put it underneath the driver's seat. Its got to be the rca's that are bad.
Posted By: i am an idiot
Date Posted: October 15, 2011 at 4:17 PM
Posted By: corrysmtx
Date Posted: October 16, 2011 at 10:50 AM
Let me get this straight, you want to hook up 2 mtx 8500s to a mtx 8302? Your fuse looks melted, what size fuse are you using 150a in 10g wire? Those 8500s are massive woofers, second largest series they make. and you want to push them with a 75x2 rated amplifier. Start with the proper equipment, follow up with a proper installer. Could be the difference between a nice system and a burning car.
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1 12" mtx 9500 4ohm dvc 1 8100d and 1 1501d almost loud enough to cover the sounds of my car dying.
Posted By: jgonzales82
Date Posted: October 16, 2011 at 6:09 PM
okay its only 1 mtx 8500 and i have the amp bridged and it should be pushing out 425 watts plus from what mtx service rep told me over the phone! And the problem was fixed it was the rca cables that where bad. i bought some monster cable rca's that were on sale and relocated the amp underneath my drivers seat. So shes back up and hits hard for what i want for now thanks guys for your help.
And for installers here in our town we have 2 but they are overpriced and their installers are mostly high school kids that really don't know much and just work there for the discount on car audio.
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