Well - my speakers caught fire.

[Mark Reccord]

There have been a few that don't.

I remember there was even sort of a "DC-coupled amp" fad back in about the 80's. For those who valued oddball specs over wisdom.

The odd-iophiles are still big on DC coupling. And they certainly fall into the camp that values oddball specs...

 

[Bob Lee (QSC)]

+1. clipped signal means no time for the speaker coils to cool. Overheated coils = transferred heat to paper cones = flaming speakers. A friend did it once to an 18 when he was running sound, and I blew a speaker once using a 25 watt amp that, when it went, blew a smoke ring out the front of the grille cloth. Poof.

No time for the speaker coils to cool? WTH does that mean?

 

[Bob Lee (QSC)]

If you're running an amp rated at 400wrms sinewave output at 4 ohms into a 400wrms rated 4 ohm cab the pedal can push the output as high as 800wrms of squarewave output. A 400wrms sinewave has the same peak voltage as a 800wrms squarewave. If you're running any overdrive or distortion you should run your cabs off an amp rated at 1/2 the cabs' rating and then you'll be OK.

Your math and electrical terminology is off, but I agree that a pedal or other processing can indeed compress the dynamic range such that if you really crank the amp you don't see dangerous peaks but the average power is really high. Possibly high enough to overheat and burn out a loudspeaker driver, particularly if is weakened in some way.

 

[Bob Lee (QSC)]

You didn't smoke the drivers with power - you did it with distortion. When amplifiers run out of headroom, it stops being able to control the movement of the cones. This causes the amp To put out square waves that cause the cones to go inward and outward as far as they can. This causes the voice coils to heat up much more than normal. Get your drivers repaired or replaced and get a seriously more powerful amp. You don't blow speakers with power , you blow speakers with distortion

No you don't. The loudspeakers don't know or care what part of the signal is clean and what part is distortion. Putting too much power into a loudspeaker will tend to burn it out. More than 90% of the power you put into a loudspeaker driver doesn't turn into acoustical energy--it turns into heat. That's about the same efficiency as an incandescent light bulb.

Imagine the heat coming off a 100-watt light bulb. That's about what you get putting 100 watts of audio into a loudspeaker driver. If you have, say, an amp rated at 400 watts into 8 ohms, and it's feeding an 8-ohm cab, you're probably putting an average of about 50 to 100 watts into the cab most of the time if you're only occasionally tickling the clip LED and not using heavy compression or other processing that squeezes the dynamic range. If you crank it up so you're running the amp into a lot of clipping, or maybe you've got lots of distortion or compression that squeezes the peaks that would otherwise alert you via the clip LEDs, you might be putting out an average of 200 watts or more. Theoretically a square wave from the amp in this example could reach 800 watts, but by that time you'd have really obliterated any musical sense in your playing.

 

[BurningSkies]

No you don't. The loudspeakers don't know or care what part of the signal is clean and what part is distortion. Putting too much power into a loudspeaker will tend to burn it out. More than 90% of the power you put into a loudspeaker driver doesn't turn into acoustical energy--it turns into heat. That's about the same efficiency as an incandescent light bulb.

Imagine the heat coming off a 100-watt light bulb. That's about what you get putting 100 watts of audio into a loudspeaker driver. If you have, say, an amp rated at 400 watts into 8 ohms, and it's feeding an 8-ohm cab, you're probably putting an average of about 50 to 100 watts into the cab most of the time if you're only occasionally tickling the clip LED and not using heavy compression or other processing that squeezes the dynamic range. If you crank it up so you're running the amp into a lot of clipping, or maybe you've got lots of distortion or compression that squeezes the peaks that would otherwise alert you via the clip LEDs, you might be putting out an average of 200 watts or more. Theoretically a square wave from the amp in this example could reach 800 watts, but by that time you'd have really obliterated any musical sense in your playing.

As the evening goes on, the air that escapes from the ports of my cabs gets warmer and warmer...Haven't popped any popcorn yet though. People are always surprised at how big an amp I use, but I've never cooked my speakers. When that does happen, I'm guessing they go from over excursion rather than coil meltdown.

 

[Bob Lee (QSC)]

What he said. Many don't get that under-powering is often more dangerous than overload. Seems even more likely if the pedal was pushing a lot of higher-frequency information.

What he said is actually wrong.

And there's no such thing as "under-powering" a loudspeaker.

 

[S-Bigbottom]

there's no such thing as "under-powering" a loudspeaker.

That is it. This topic never needs to be discussed again.

Now waiting for someone to say you are wrong.

 

[Mark Reccord]

That is it. This topic never needs to be discussed again.

Now waiting for someone to say you are wrong.

Of course he's wrong. Why would we assume that an engineer working for one of the leading producers of pro level power amps (and lots of other stuff) knows what he's talking about?

 

[BurningSkies]

Of course he's wrong. Why would we assume that an engineer working for one of the leading producers of pro level power amps (and lots of other stuff) knows what he's talking about?

Bob's worried that his secret start up business of low wattage saw-tooth and square wave only amplifiers will be DOA.

 

[Passinwind]

Bob's worried that his secret start up business of low wattage saw-tooth and square wave only amplifiers will be DOA.

I've got the trademark on Bees In A Jar, but Bob's cool and I might be open to a licensing arrangement.

 

[Mark Reccord]

Bob's worried that his secret start up business of low wattage saw-tooth and square wave only amplifiers will be DOA.

This is clearly the case.

 

[BurningSkies]

I've got the trademark on Bees In A Jar, but Bob's cool and I might be open to a licensing arrangement.

I'm surprised that isn't already some kind of pedal made by a dude breadboarding in his basement...with all the knobs named obtuse things so that you can't figure what the hell they do.

They call that boutique

 

[Mark Reccord]

This thread continues to deliver.

 

[BurningSkies]

This thread continues to deliver.

Neckbeards rejoice!

 

[BurningSkies]

I bet they can customize the color of the electrical tape for you if you want.

 

[S-Bigbottom]

I bet they can customize the color of the electrical tape for you if you want.

I want bacon tape. That will add a good flavor to my tone.

 

[Passinwind]

I want bacon tape. That will add a good flavor to my tone.

But does it smell like bacon when it fries?

 

[BurningSkies]

I want bacon tape. That will add a good flavor to my tone.

Oddly, the other night I had 'duck bacon'. It was pretty good but I think you could have just called it smoked duck. I wonder if they smoked it in a speaker cabinet.

 

[S-Bigbottom]

But does it smell like bacon when it fries?

They do have scented, just not bacon.
Maybe you can make an amp that we can use the heat to cook on? Like making food with your engine by placing it in foil and setting it on the manifold.

 

[Bass_Pounder]

This thread continues to deliver.

You guys should see some of the posts in this thread from a few days ago:

Louder Rig | TalkBass.com