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My QSC Power Amp keeps blowing speakers


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I have a 1500 watt QSC power amp and it keeps blowing speakers. I was hoping someone on here might be able to shed some light on why this could be happening. The power rating is right and the speakers should have no problem handling the load, but it has blown 2 of my monitors and then a friend borrowed it and it blew 4 of his 15's and 2 horns. Any ideas???

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amps don't blow speakers, people blow speakers.

 

perhaps if you tell us the model of power amp, the model of the speakers in question, what mixer, processing, program material are involved, as well as how it was all hooked up and under what operating conditions it was being run... we can then inform you on where you screwed up.

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Are you matching RMS watts of the amp to an RMS watts rating of the speakers, at the correct ohms?

Are you driving anything into distortion?

Are limiters on the amps engaged to prevent damage?

Are HPF's engaged on the amps (or otherwise in the system) to keep too much low frequency power out of speakers that aren't rated for it?

Are your operators trained, and listening with a good ear?

 

As noted above - some more details will help!

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user error or amp failure. i dont see any other alternatives.

 

its possible although i think unlikely that the amp could be putting out enough DC to cause failure or some such other whimsical disaster but i'm guessing that the red lights were on solid feeding the 45 watt Kustom speakers.

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Coaster. They were 300 watt Peavey floor monitors. I could see how those might get overloaded and blow, but my buddy was running 700 watt mains and it blew 4 15's and 2 tweeters and he had the gain turned at about halfway. They were both rated at 8 ohms. No 45 watt kustom speakers here. I might be kind of new at this but I'm not clueless. Please be respectful.

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Coaster. They were 300 watt Peavey floor monitors. I could see how those might get overloaded and blow, but my buddy was running 700 watt mains and it blew 4 15's and 2 tweeters and he had the gain turned at about halfway. They were both rated at 8 ohms. No 45 watt kustom speakers here. I might be kind of new at this but I'm not clueless. Please be respectful.

 

 

we still need model numbers in order to accurately advise you. Manufacturers use different ratings for marketing purposes sometimes. We need to differentiate between RMS, program and peak.

 

we also need the model of the amp.

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Coaster. They were 300 watt Peavey floor monitors. I could see how those might get overloaded and blow, but my buddy was running 700 watt mains and it blew 4 15's and 2 tweeters and he had the gain turned at about halfway. They were both rated at 8 ohms. No 45 watt kustom speakers here. I might be kind of new at this but I'm not clueless. Please be respectful.

who cares what the gains were set at. Has very little bearing.

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1500 watts? 300 watts? no problem. it worked exactly like it should have?

 

i remember i used to be friends with a guy who put a heavily modded 350 v8 into a monza; it just bolted right in. now this engine was modded with a giant 4bbl carb, uberlump cam (like 300+ adv duration intake), big valve heads and would easily spin 8000+ rpm. i think the car is rated for maybe 45 horsepower or so, do you see where this is going? true story though.

 

the first time he stepped on it the car twisted up real bad, blew the windshield clean out in a million pieces, shattered the door glass and rear window, tore the doors up and the car basically sat on three wheels from then on. it looked like he hit a tree, but it was just the power from the engine.

 

he of course beamed ear to ear about this. it is rather funny. but he didnt blame the engine.

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1500 watt into 300 watts is a recipe for disaster. 1500 watts into 700 watts isn't so good either.

 

Let us know the details of what you've got - people will be glad to help you get to the root cause! We want you to succeed.

 

Amps are usually rated RMS watts. Speakers vary a lot in how they are rated. If not stated, spaeakers are often rated at peak watts, which are about 4X as optimistic as RMS power. Are the speakers 4 ohm or 8 ohm? Look carefully at what you have.

 

An amp with the gain turned up half way can still deliver it's peak power, depending on the signal level it's being fed.

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1500 watts? 300 watts? no problem. it worked exactly like it should have?


i remember i used to be friends with a guy who put a heavily modded 350 v8 into a monza; it just bolted right in. now this engine was modded with a giant 4bbl carb, uberlump cam (like 300+ adv duration intake), big valve heads and would easily spin 8000+ rpm. i think the car is rated for maybe 45 horsepower or so, do you see where this is going? true story though.


the first time he stepped on it the car twisted up real bad, blew the windshield clean out in a million pieces, shattered the door glass and rear window, tore the doors up and the car basically sat on three wheels from then on. it looked like he hit a tree, but it was just the power from the engine.


he of course beamed ear to ear about this. it is rather funny. but he didnt blame the engine.

was he from Iowa??

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Ehh...{censored} it. I'm out of town and don't know the model of the speakers. I'm just gonna sell the power amp and get a powered mixer. Let's go bowling.

 

 

Unless you understand what happened and why, it's probably going to happen again.

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Ehh...{censored} it. I'm out of town and don't know the model of the speakers. I'm just gonna sell the power amp and get a powered mixer. Let's go bowling.

 

 

Your friends will really appreciate this I'm sure, and I suspect they'll soon discover that it gets expensive hangin' around.

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judging things based on "general" assumptions could have been what got the OP where he is now.

 

That is assuming that he's not just a troll trying to get us all excited. I expect that he was and was let down when he realized that we all just wanted to deal with it logically based on real numbers/specs.

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Generally, amp model numbers reflect total power...1500W is probably 750WPC into 2 Ohms and probably 350WPC into 8 Ohms

 

 

The problem is that an amp like the GX series is an amp that is optimized for 4 ohms min load and puts out more than expected based on the assumption into 8 ohms.

 

Specifics are important with the less a user really understands.

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