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Did I blow out my amp, speakers, or both


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#1 dembits

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Posted 15 May 2006 - 03:37 PM

This past weekend, I was playing at a party where I had some of my equipment malfunction and I am trying to find out what happened. I was playing with my monitors really close to my ear, so I didn't hear anything until I took a break to go to the bathroom. When I did, I heard that the main speakers were only playing highs. When I got back behind my rig, there was a funny smell, and the clipping light on my amp was on. I tried turning it off and back on, to see if I had triggered an automatic power off in the speaker, but it didn't fix the problem. Since it happened, I have been afraid to turn it on to troubleshoot the problem because I do not want to make things worse. I thought that I was running proper power into the speakers and I never allowed my mixer LED to go into the red, so I assumed that I would be fine. This is only the second time that I have used this setup, so everything is pretty much brand new. The equipment that I am using are a XLS 6o2A amp with two MTX TP112 speakers running parallel on one channel. Any help that you can provide would be great.

#2 Stephane

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Posted 15 May 2006 - 08:27 PM

looks like you burnt your speaker/crossover, just plug the amp alone and turn it on you'll see it did probably went in protect mode, your speaker are only 300 watts peak witch is not much continue and i'm not sur if they are 150 watts rms and a 602 @ 8ohms =380watts more than twice good luck.

#3 dembits

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Posted 16 May 2006 - 01:40 PM

QUOTE(Stephane @ May 15 2006, 05:27 PM)
looks like you burnt your speaker/crossover, just plug the amp alone and turn it on you'll see it did probably went in protect mode, your speaker are only 300 watts peak witch is not much continue and i'm not sur if they are 150 watts rms and a 602 @ 8ohms =380watts more than twice good luck.


Then did I do my math wrong. If I have (2) 150 watt RMS (300 Peak) 8 ohm speakers running parrallel on one channel, then shouldn't 600 watts @ 4 ohms be about right to give proper headroom? Perhaps it is the workmanship of the speakers or the crossovers, but for both of them to blow, seems weird to me.

#4 Stephane

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Posted 16 May 2006 - 05:38 PM

QUOTE(dembits @ May 16 2006, 01:40 PM)
 
QUOTE(Stephane @ May 15 2006, 05:27 PM)
looks like you burnt your speaker/crossover, just plug the amp alone and turn it on you'll see it did probably went in protect mode, your speaker are only 300 watts peak witch is not much continue and i'm not sur if they are 150 watts rms and a 602 @ 8ohms =380watts more than twice good luck. 
 
  
  
Then did I do my math wrong. If I have (2) 150 watt RMS (300 Peak) 8 ohm speakers running parallel on one channel, then shouldn't 600 watts @ 4 ohms be about right to give proper headroom? Perhaps it is the workmanship of the speakers or the crossovers, but for both of them to blow, seems weird to me.  
  
  
  
Sorry for this I did met one or the other here for speaker or crossover or maybe both, yes  two 8 ohms in parallel will give you about 4 ohms and a 602 @ 4 ohms will give about 600 RMS, you said make sure the mixer was not going in red but did your amp was setup to not clip before your mixer? like i said i do not want to bash or *beep* against your speakers  but they are not what i would call 'reel Professional speaker like JBL or EV'' so may not be exactly made to take abuse like pro stuff, so may not what you need for the job you are trying to do. Look at  these speakers that are rated for 250 watts would be a nicer match for you http://www.jblpro.com/JRX/JRX115.htm  and take a look here http://www.crownaudio.com/apps_htm/apps-ppa.htm this will give you a quick idea what crown suggest. Good luck.

#5 Bud Bolf

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Posted 16 May 2006 - 07:33 PM

Hi Dembits,

You said:
QUOTE
The equipment that I am using are a XLS 6o2A amp with two MTX TP112 speakers running parallel on one channel.


What is running off of the other channel?

Yes two MTX TP112's paralleled together equals 4 ohms.
With the rule of thumb that you use 1.5 to 2x of Power Amp RMS per the RMS/Continuous rating of the Speaker/Cab then you need between 450 watts (1.5x)
to 600 watts (2x)
Read this: How Much Power do I need.

What Stephane was referring to is if you set your "Gain Structure" correctly.
Your mixer may not be clipping but your amps could still be redlined and Clipping madly!

Here are a couple articles on Gain Structure.
1) Gain Structure 1

2) Gain Structure 2

These Articles and many others can be found at ProSoundWeb's Study Hall.
Link here: Study Hall

As far as your speakers and Amp go, you will just have to check them out.
First hook up your amp and feed a signal to it with no Speakers attached, turn it on and see if the Green signal lights react to the Input Signal and that all looks ok.
Next if you have another speaker (that you know works) hook it up to the Amp and see if it works properly on both channels.
This way, at least you will know that your Amp is OK.

Next check your Speaker cab's, hook them up to your home Stereo or the XLS 602 if the Amp checked out ok.
Gently move the Speaker cone in and out, do they move?
If your Amp checks out ok but your speaker cabs still only have the highs, there is a good possibility that the Speakers are toast.
If they are under Warranty take them in for repair, if the Amp did not pass it's test take it in for Servicing.

If the Speakers are not under any warranty, then pull one of them out of the cab and check it out. Check the leads in the Speaker, it may have had an over excursion and broken the leads to the cone.

Dig in and let us know what you find.

Good Luck,
     Bud
PS. If it turns out that you did fry your speakers, then read all about Gain Structure and make sure that yours is correct.

#6 Stephane

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Posted 16 May 2006 - 08:45 PM

Thanx Bud to explain for me, that's my french side sometime i'm missing a bit of vocabulary  biggrin.gif

#7 Bud Bolf

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Posted 16 May 2006 - 09:08 PM

QUOTE(Stephane @ May 16 2006, 09:45 PM)
Thanx Bud to explain for me, that's my french side sometime i'm missing a bit of vocabulary  biggrin.gif


Hi Stephane,
No problem, I knew exactly what you were talking about and I think that you hit the nail on the head, so to speak.
I just thought I would add a bit more too your point for Dembits and anyone else that can use the information.

Another thing that will help with System Setup is a Audio Test CD by Micheal Binks.
The link is here: Binks Audio Test CD

It is a large file but if you have the ability to Burn CD's or have a friend that can,
burn a CD (I split it up on two CD's) and you can use it to check Crossover points, Gain Structure, etc.. It is invaluable!

Later,
   Bud

#8 dembits

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Posted 18 May 2006 - 10:34 AM

So I hooked my speakers up to a different amp and had the same problem, so I think that it is safe to say that the speakers blew. I knew that they were not the best quality, but they worked quite well at a test gig, so I assumed that they would work out. I will probably have to save up to buy the JBL JRX-115s that are in the diagram in the link Stephane sent. I have not had a chance to test the amp yet to see if there was a problem there too, because I don't have any speakers that can take the wattage. But thank God (or whatever you believe in) for the 3 year warranty on that. Thanks for the help and I will read through the gain structure articles to learn about that.