Jon or glass or anyone else with any ideas....technical problem

 

Gold Member
Username: Insearchofbass

Post Number: 1591
Registered: Jun-04
i went out to my car last night after having played my system with my jl 12 w 0 earlier that day and everything was fine. Now heres the wierd thing with none of my other amps on i go to adjust my gains and stuff on my mtx 81000d and nothings seems to be responding to my turns on the dials really. Then i listen close and i hear a high pitched whine coming from my amp that i never heard before. Any ideas on whats going on? Im afraid to turn the amp back on because i dont want to blow my amp now.
 

Gold Member
Username: Carguy

Post Number: 2505
Registered: Nov-04
Is the amp in warranty? Could the sound be coming from the fan?
When you say "nothings seems to be responding", what control are you adjusting? Is it the gain? The bass boost/crossover? What other amps do you have besides the MTX? How did you have them turned off? Did you disconnect the power wires?
Do you have capacitors? What is the power reading on the MTX amp?
 

Gold Member
Username: Insearchofbass

Post Number: 1592
Registered: Jun-04
not sure but i doubt its still under warranty. there isnt any fan on that amp that i know of. two of the knobs seem to respond very little when i turn them all the way up. (bass boost and gain). I have two other amps the mtx 2150x and the mtx 275x. I have all three amps hooked to toggel switches in my center console so i can turn them off and on I also have a kill switch to turn everything off at once. I have no capacitors. The mtx 81000d is rated 1500 at 2 ohms im running it at 8 ohms right now off a jl 12 w0 8 ohmer my other 2150 x is rated 120 x 2 and my 275 x is rated like 80 x 2.
 

Gold Member
Username: Insearchofbass

Post Number: 1593
Registered: Jun-04
those ratings might be at 4 ohms stereo on the other 2 amps
 

Gold Member
Username: Jmloughrey

Farmington, CT

Post Number: 1229
Registered: Jul-04
could it be possible the amps just not happy running at 8 ohms?
 

Gold Member
Username: Carguy

Post Number: 2508
Registered: Nov-04
I've checked the MTX amp and it doesn't mention supporting 8ohms. Any reason why you're using in that mode? Some amps will have problem if you don't meet the ohm requirements.
Have you tried testing the amp without any rca input connected? Does it still produce noise?
There's nothing in the amp besides the fan that will make noises. Maybe it's coming from the relays/coils inside? You'll know better once it's opened.
Unless the amp is having problems, I'd just use it till it breaks down. If you can, change your sub wiring so that it's within the limit of MTX amp.
 

Gold Member
Username: Insearchofbass

Post Number: 1594
Registered: Jun-04
becasue im running one jl 12 w 0 8 ohmer
 

Gold Member
Username: Insearchofbass

Post Number: 1595
Registered: Jun-04
im going to call mtx
 

Gold Member
Username: Insearchofbass

Post Number: 1596
Registered: Jun-04
i called mtx and described my problem and they said that they think the jls coil is now damaged. which it could be.( because what i didnt tell him was that i did a test tone burp on the sub and pushed it only slighly earlier yesterday) They said that the wine sounds like the amp is going into protect mode because of the coil possibly being damaged. Man jl 12 0's arent very resiliant i listened close too.
 

Gold Member
Username: Insearchofbass

Post Number: 1597
Registered: Jun-04
theres 50 bucks down the drain if it is blown
 

Gold Member
Username: Carguy

Post Number: 2512
Registered: Nov-04
If you have DMM, then test the sub's resistance. See if you still get 8ohms.
 

Gold Member
Username: Insearchofbass

Post Number: 1600
Registered: Jun-04
you mean an ohms tester?
 

Gold Member
Username: Carguy

Post Number: 2515
Registered: Nov-04
Yes.
 

Gold Member
Username: Insearchofbass

Post Number: 1601
Registered: Jun-04
by the way mtx said its fine to run that amp in 8 omh just as i expected
 

Gold Member
Username: Insearchofbass

Post Number: 1602
Registered: Jun-04
ok will do isaac.....so if i test it and reads off of 8 ohms then its damaged right? im not experienced in this area. plus ive never blown a sub yet. but this might be a first.
 

Gold Member
Username: Carguy

Post Number: 2516
Registered: Nov-04
Well if the coil is blown, then you will either get no reading or a value much lower than 8 ohms.
Have you tried testing the sub with another amp or another speaker with the same amp?
According to MTX, they're saying the amp is going into protection mode. The only way it'll happen is if the sub's resistance is out of the amp's ohm requirements.
 

Gold Member
Username: Insearchofbass

Post Number: 1604
Registered: Jun-04
ill pull the sub and test it first but mtx is saying the coil is damamged but not blown from what i take it.....it mistifies me that the amp woulsd still play if it was in protect mode....id think it would shut down all together
 

Gold Member
Username: Carguy

Post Number: 2517
Registered: Nov-04
Sometimes those guys get "brain cramp" and give wrong advice.
Try and find out where the sound is coming from (amp or the sub).
 

Gold Member
Username: Insearchofbass

Post Number: 1605
Registered: Jun-04
the amp
 

Gold Member
Username: Carguy

Post Number: 2520
Registered: Nov-04
If you unhook everything on the amp except the power wires, does it still produce noise?
By pass your switch setup too.
 

Gold Member
Username: Insearchofbass

Post Number: 1607
Registered: Jun-04
it didnt before this problem and no amps are powered on with my switches off so its not line feed if thats what your checking for
 

Gold Member
Username: Carguy

Post Number: 2526
Registered: Nov-04
I would take the amp out and connect it to the battery straight for testing.
 

Gold Member
Username: Insearchofbass

Post Number: 1608
Registered: Jun-04
your thinking its my amp huh thats not good if i had to choose id wish the sub was bad rather than the amp
 

Gold Member
Username: Insearchofbass

Post Number: 1609
Registered: Jun-04
i sware if this amp is badim done messing with my system for quite a while....like when I get a new car that long lol......after that ill just help other people with their stuff around here
 

Gold Member
Username: Carguy

Post Number: 2536
Registered: Nov-04
Well the amp doesn't have much that'll make noise so easier to test. Very quick too. So if the amp passes the test, then you know the problem is with the switch or the sub.
 

Gold Member
Username: Insearchofbass

Post Number: 1610
Registered: Jun-04
well i hooked the jl 12 0 to my cousins amp in his car and its ok so its my amp or my wiring because my remote is working to turn the amp on but no sound at all is coming from my amp now except for the low pitched whistle sound when i put my ear close to the amp
 

Gold Member
Username: Insearchofbass

Post Number: 1611
Registered: Jun-04
i called mtx and they said worst case repair is 95 dollars including shipping return
 

Gold Member
Username: Carguy

Post Number: 2581
Registered: Nov-04
"Worst case" repair means they'll be replacing the board for $95. Which makes you wonder why they're charging so much for the amp in the first place?
 

Gold Member
Username: Insearchofbass

Post Number: 1612
Registered: Jun-04
yeah thats what he said about the board too....and i was asking myself the very same question.
 

Gold Member
Username: Insearchofbass

Post Number: 1613
Registered: Jun-04
hes saying it could be the power supply but i was wondering why the remote turn on is working then...i mean the light on the amp is on....i was also wondering this...if you clipped an amplifier hard enough could you blow a power supply?
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