Amp went poof - AVS Forum
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post #1 of 21 Old 03-01-2013, 07:34 AM - Thread Starter
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I am wondering if any tech types can weigh in on a situation that recently occurred.
While sitting around the other day an obnoxious noise emanated from one of my theater speakers like a death throw.
It was then silent.

I checked the multi channel amp and the light corresponding to the dead speaker was lit.
I took the dead speaker to my local repair shop and explained what had transpired.
The cones are fused and no longer move.
The tech there said it sounded as though a DC burst was sent from the amp and fried the speaker.

I assume this burst is not a good thing and am now wondering if this might occur with the other channels and remaining functioning speakers.

I then contacted the amp manufacturer and told him my story.
He said without looking at the damaged amp module he could not say what happened but could state that it was not a DC burst.

I have never heard of this and wonder if this type of occurance does happen on occasion, it makes home theater a very costly hobby.
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post #2 of 21 Old 03-01-2013, 07:55 AM
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What brand/model?
I hope its not a Behringer..


Just my $0.02... wink.gif
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post #3 of 21 Old 03-01-2013, 08:10 AM
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It's not a DC burst, but could very well be a short that caused an AC burst. Not that it makes a difference if it's AC or DC. Too much current caused the speaker to overheat.
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post #4 of 21 Old 03-01-2013, 08:19 AM - Thread Starter
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I am not saying the brand or model at this point as I am hopeful for a positive resolution to this issue.
Naming names at this point would not be beneficial in negotiating compensation.



Quote:
It's not a DC burst, but could very well be a short that caused an AC burst. Not that it makes a difference if it's AC or DC. Too much current caused the speaker to overheat.


I am concerned that this might occur again within the remaining modules.
I suppose the best course would be to not use it until the cause of the meltdown is determined.

Surely this must have been a one in a million occurance though.
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post #5 of 21 Old 03-02-2013, 10:44 AM - Thread Starter
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can I put I fuse or other type of protection somewhere in the speaker cable to prevent an occurance like this from happening again?
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post #6 of 21 Old 03-02-2013, 11:23 AM
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Quote:
Originally Posted by kiwi2000 View Post

can I put I fuse or other type of protection somewhere in the speaker cable to prevent an occurance like this from happening again?

Yes.

Start out with something in the 3-5 amp range and increase if it blows in normal use.
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post #7 of 21 Old 03-02-2013, 11:27 AM
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Quote:
Originally Posted by kiwi2000 View Post

I am wondering if any tech types can weigh in on a situation that recently occurred.
While sitting around the other day an obnoxious noise emanated from one of my theater speakers like a death throw.
It was then silent.
.

Output stage transistor shorted out, effectively connecting one of the power amp's power supplies to the speaker, which fried the woofer.

noise was mostly the raw output of the power supply experiencing an overcurrent fault.
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post #8 of 21 Old 03-02-2013, 11:37 AM
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Quote:
Originally Posted by arnyk View Post

Yes.

Start out with something in the 3-5 amp range and increase if it blows in normal use.

A fuse won't work...
It is too slow to react to a surge/spike...
By then the damage is done..

Just my $0.02. wink.gif
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post #9 of 21 Old 03-02-2013, 11:50 AM
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Quote:
Originally Posted by arnyk View Post

Output stage transistor shorted out, effectively connecting one of the power amp's power supplies to the speaker, which fried the woofer.

noise was mostly the raw output of the power supply experiencing an overcurrent fault.

That seems to me to be a likely explanation. Put a voltmeter (Fluke/whatever) on the receiver speaker output for the speaker that blew. What does it read?
Quote:
Originally Posted by M Code View Post

A fuse won't work...
It is too slow to react to a surge/spike...
By then the damage is done..

Just my $0.02. wink.gif

I don't think you know enough about what actually happened to conclude that. If arnyk is right, then certainly a fuse could have protected the speaker.

~~~
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post #10 of 21 Old 03-02-2013, 12:17 PM - Thread Starter
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Quote:
that seems to me to be a likely explanation. Put a voltmeter (Fluke/whatever) on the receiver speaker output for the speaker that blew. What does it read?


Do you mean measure the speaker at the speaker input terminals?

If not the amp module is already en route to the service center too late to measure anything.

Where and how exactly would l install the fuse?

Why did the protection circuits of the amp not trip???? It has many, none tripped.
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post #11 of 21 Old 03-02-2013, 02:32 PM
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Quote:
Originally Posted by kiwi2000 View Post




Do you mean measure the speaker at the speaker input terminals?

If not the amp module is already en route to the service center too late to measure anything.

Where and how exactly would l install the fuse?

Why did the protection circuits of the amp not trip???? It has many, none tripped.

The speaker can't fry itself. So the amp/receiver is the entity of interest if we are wanting to get to root cause of this problem. (by the way, I really feel for you... you got the bad end of the stick on this one) So the voltage measurement I would be interested in would be the output on the amp/receiver that was driving the speaker that died.

To be effective, a fuse needs to be in series with the current. So it would have to be inline with the current flow to the speaker (as opposed to across the speaker input terminals). I've got a 20 year old pair of Infinity speakers with fuses on the back... nicely implemented I must say. smile.gif I can post a pic if you are interested.

~~~
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post #12 of 21 Old 03-02-2013, 03:32 PM - Thread Starter
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I cannot measure the module now as stated. It is in transit.
I will not have this occur ever again and frankly have never heard of this happening, ever.

Please post the fuse photo. thanks!

Although if no answers and solutions to prevent further damage to any other drivers or the amp itself are offered this product will be deleted.
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post #13 of 21 Old 03-02-2013, 04:19 PM
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well since you dont want to offer any watts or ratings. I will assume you just added a 400 watt/channel emotiva amp to your 5 watt max radio shack speakers and over drove the one. That being the case, I would recommend replacing all your speakers. that would be a better fit for your amp.

Life is enjoyable with good quality
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post #14 of 21 Old 03-03-2013, 06:25 AM - Thread Starter
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well since you dont want to offer any watts or ratings. I will assume you just added a 400 watt/channel emotiva amp to your 5 watt max radio shack speakers and over drove the one. That being the case, I would recommend replacing all your speakers. that would be a better fit for your amp.

That is not helpful and not appreciated.
Go offer these cheeky unhelpful comments somewhere else please.
Hope that what happened does not happen to you!

I explained why I would not reveal details as of yet.
The issue occurred while viewing TV just on background volume,no strain there.
Even my 5 watt max radio shack speakers could have handled it.biggrin.gif
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post #15 of 21 Old 03-03-2013, 01:25 PM
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Here is the back of one of my (old) Infinity speakers, complete with fuse:



The fuse is mounted to be in-line with the current flow. In effect, the fuse is between one of the wires to the speaker and the matching terminal on the speaker for that wire.

I think what might be troubling some of the posters in this thread is that you have not provided a lot of information to go by. Providing more info generally means more on target assistance will be given. I am clearly speculating, but I think that is what is going on.
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post #16 of 21 Old 03-03-2013, 06:00 PM
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With no idea what you have for an amp, distortion levels, power ratings etc. Are you driving 40 year old speakers, or a pair of 5 watt radio shack. Volume levels, are the speaker cones dried out? My guess is as good as anyone elses.
For you to cast judgement on my guess.... You are the one with the equipment.

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post #17 of 21 Old 03-14-2013, 07:31 PM - Thread Starter
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The amp module has finally been repaired and is enroute back to my location. I have had the speaker repaired, luckily parts were still available. I am hopeful the factory that manufactured the amp module will eventually spring for the repairs to the speaker.

They state it could have possibly been their product that failed so spectacularly but unlikely. They suggested maybe a source component caused the failure. I have now had the pre amp tested for anything unusual and have spoken at length with the pre amp manufacturer’s tech department about this issue. It is their conclusion that the failure resides solely within the amplifier which in turn caused the speaker to blow. I have also had conversation with the repair depot that fixed the speaker; they have the same opinion as well.

I then contacted the two other source component companies in my system, Blu ray player and my digital HD cable service both state their products could have in no way caused the issue that occurred to the amp and speaker unless they were connected directly to the amp, which they were not.

My dilemma is do I trust this amplifier enough to put it back in to service? I have not used the amp since the failure took place. I am very hesitant to re instate it after I re install the module. The factory has been unable to provide any assurances that this fault will not occur again to the amp or speakers connected to it or how to prevent such a failure.

The service depot made up some inline fuses for me to add to the positive side of each speaker terminal at the power amp outputs. I am bi wiring but they state only the woofers need this type of fused protection.
Will this fuse system stop another occurrence should it occur?

Should the amp factory not be able to have diagnosed the failure and know what the issue was and how to avoid another occurrence going forward?

Would or will another amp manufacturer fare any better?


I am amazed by this failure and now doubt has caused me to try to avoid a re occurrence at all costs.
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post #18 of 21 Old 03-14-2013, 08:03 PM
 
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One of the main helps in this forum is to reach out to others who own the same equipment to see what they've experienced with the same gear and if anyone has had your symptoms. It is not a knock against any manufacturer or bad mouthing them, unless you start to bad mouth them. Since you have not mentioned the brand/model, no such owners can offer helpful advice.
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post #19 of 21 Old 03-14-2013, 09:02 PM
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I agree and after some research I went with the Cine Nova, cheapest and easiest to repair, good warranty also.

That still your amp? Was it the Marantz 8003 or 8801 used with this? smile.gif

Bi wiring? Really?

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post #20 of 21 Old 03-15-2013, 06:23 AM - Thread Starter
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post #21 of 21 Old 03-17-2013, 05:46 AM - Thread Starter
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