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Author Topic: Paudio c15 600EL coil smell, too much power?  (Read 3164 times)

John Roberts {JR}

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Re: Paudio c15 600EL coil smell, too much power?
« Reply #10 on: August 09, 2016, 04:57:23 pm »

So then somehow a more powerfull signal got into the amps and pushed them into clipping,

if the smell is "pre smoke smell" then it means these p7000s are too much for these drivers. They tend to start smelling even with the amp away from the clipping point if the program is continuously rich enough below 100hz.

That's weird. 750-800W peak shouldn't be too much for a driver rated at 600w continuous AES.
The heat comes from average power not peak...

JR
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Mark Wilkinson

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Re: Paudio c15 600EL coil smell, too much power?
« Reply #11 on: August 09, 2016, 05:27:16 pm »

The heat comes from average power not peak...

JR

John, in over my head here...but is it possible this is a case of apparent power becoming more a function of real power (due to rise in coil resistance), than of reactive power when voice coil is cold?   ala 1.7 in this powersoft note http://www.powersoft-audio.com/en/downloads/technical-notes/804-how-to-setup-limiters/file  ????

Limit light's could look the same, but with even more heat going to coil ??
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Ivan Beaver

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Re: Paudio c15 600EL coil smell, too much power?
« Reply #12 on: August 09, 2016, 06:31:18 pm »

That's right, and it seems to me that is what's happening here, event with the amps away from the clipping point.

But they do tend to start hitting the clipping point when i run them at a constant level for long enough with very bass heavey program.

Can thermal compression be the cause of this?
How does the amp respond to coil overheating/impedance rising. I understand the total output power of the amp will drop, but can this make it hit the clipping point earlier then when it's running a cold coil?
I HIGHLY doubt the amp is changing anything because of the speaker changing impedance.

If anything, (if the clip light was actually looking at the output vs input signals-like old Crowns-but not most amps) the clip light should be going on early and then not as much with a higher impedance load.

I SUSPECT that the program material has changed (unless you are running the same material (meaning the same song the whole time) and is putting out a higher drive voltage-EVEN IF you are not changing your fader levels.

Here is one other "possible" answer (but I don't think it is right-but just throwing it out there).

Let's say that the clip LED is for a specific output voltage.

When the driver is cold, the impedance will be lower-possibly pulling down the available output voltage.

When it heats up, the impedance is higher-so the amp can swing more voltage.  So the LED turns on.

This is a typical indication of a "sloppy" power supply.

I installed quite a few P7000s years ago.  I found the sound to be very "loose" on the low end.  Especially when compared to a Crest CA amp of similar power.

The Crest were A LOT tighter sounding and had more impact.

This was using the same full range speakers, but in different rooms.

But the results were the same each time.
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Paul G. OBrien

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Re: Paudio c15 600EL coil smell, too much power?
« Reply #13 on: August 09, 2016, 06:40:10 pm »

That's weird. 750-800W peak shouldn't be too much for a driver rated at 600w continuous AES.

Actually the data I see says that driver is 1200w AES but go lookup what the AES standard is. They don't use sine waves for these test standards anymore it's a bandwidth limited noise signal with 6dB crest factor which is the difference between the dynamic peak of the signal compared to the mathematical average level. That means the driver can really only handle around 300-400w of continuous tones for any extended period of time so yeah a P7000 is more than capable of melting the drivers with the right program material. The solution is to use better limiters, maybe a DSP processor with both RMS and peak limiting.
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Eugen Jeličić

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Re: Paudio c15 600EL coil smell, too much power?
« Reply #14 on: August 10, 2016, 04:54:35 am »

Ivan, so your theory is that since the p7000s has a sloppy power supply, when the impedance is lower the power supply becomes a limiting factor so the amp never hits the voltage clipping point, but when the impedance goes up there is no need for the power supply to push that much current into the amp so the output voltage will be able to go up (the PSU is not a limiting point anymore) and that will cause clipping?

Of course it might simply be that i didn't test the system with enough different program material to see will the amps really clip.


Paul, you have been looking at the V2 of this driver. This is the first version, it's rated at 600W AES.

So yes, it seems like the p7000s is too much.
That's not really a problem i just need to turn it down a bit. But got used to having amps not powerfull enough for the box so i always see the clipping point as a warning sign.

I do understand that clipping is not what melts a coil, heat is. So, too much unclipped power can melt the coil too.

Ivan, yes i can agree, the p7000s is terrible for subwoofers.
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Ivan Beaver

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Re: Paudio c15 600EL coil smell, too much power?
« Reply #15 on: August 10, 2016, 06:31:03 am »

Ivan, so your theory is that since the p7000s has a sloppy power supply, when the impedance is lower the power supply becomes a limiting factor so the amp never hits the voltage clipping point, but when the impedance goes up there is no need for the power supply to push that much current into the amp so the output voltage will be able to go up (the PSU is not a limiting point anymore) and that will cause clipping?


I said it was a possibility-but not really a "good" possibility.

The better idea is that the level coming out of your mixer was louder later on, even if you didn't turn the faders up.

Most likely due to the program material being louder
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Ivan Beaver
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Re: Paudio c15 600EL coil smell, too much power?
« Reply #15 on: August 10, 2016, 06:31:03 am »


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