Running Distortion - Amp Risks

[Lowtonejoe]

Waveform is waveform. What difference does it make if the power amp generates the waveform, or if it reproduces the same waveform fed into it externally? The only difference is that the external waveform can be turned up to the power amp clipping threshold, but also turned down, whereas power amp clipping occurs at a fixed amplitude determined by the amp design.

So the amps ability to perform is in no way compromised by being pushed out of operational tolerances?

Which would be different from just reproducing a waveform, right?



Joe.

 

[Richard Lindsey]

it becomes much more reasonable.

But remains mistaken.

 

[Richard Lindsey]

So the amps ability to perform is in no way compromised by being pushed out of operational tolerances?

Which would be different from just reproducing a waveform, right?



Joe.

Well, it loses its ability to reproduce the waveform accurately, if that's what you mean.

Regardless, the bottom line is this: if you want to argue that amp clipping kills speakers and clean reproduction of a clipped signal *at the same amplitude* doesn't, then you have to explain why and how the content of the signal delivered to the speaker differs in the two cases, and if such a difference exists, why and how it should be harmful in one case. No one here has come close to doing that. If the speaker is being damaged in one case but not another, that means it has to be getting a quantitatively or qualitatively different signal in one case.

Again: try distorting a bass amp. Record that. Then feed that recorded signal through a much bigger, clean amp. Put both that signal and the original signal through speakers *at the same amplitude*. Presumably, if the recording was well done, the two signals should look almost identical. But in one case the amp is stressing and in the other it's not stressed at all; so by your logic one signal will damage the amp and the other won't. So explain why that should be so.

 

[Richard Lindsey]

For those who think there is a risk, could you explain what that risk is and what general safe operating levels would be? Also, what would be indications of unsafe usage?

The thing is I just got all this new gear, and with my old crappy stuff I didn't care if I beat the hell out of it. But I'm in it for the long haul with my new stuff. I am just looking for some guidelines and possible things to look out for.

Sorry for taking part in thread drift. To get back to your query, I don't think anyone feels you're at much risk if you keep your amp settings moderate.

But if you want an absolute guarantee that you'll be fine no matter what you do, we can't give you that. Nor can we give you an exact number beyond which it's not safe to turn up your amp.

There isn't a hard and fast rule as to what signals danger. Often, you may hear distortion, but if you're already using distortion, you may not hear the extra distortion. Sometimes a component can be damaged without your hearing audible stress. I'd just say, be careful, avoid too much bass boosting, and occasionally test your gear out clean at volume; that may help you identify potential problems that could get lost under the distortion you normally use.

 

[greenboy]

One of the saving graces of effect-type distortion is that it appears to be much louder than a typical clean signal from the same instrument, and most of its energy is NOT in the lower overtones but in midrange and higher partials (and their increased sustain). Unless one is also adding a hella lot of bass boost to their distortion the demands for power a screaming distortion makes are not as great as one would often imagine.

To test this premise in the real world take a two-channel guitar combo and set up an ultragain distortion sound that just screams on one channel and a good full clean sound on the other that seems to be able to keep up. Run a line out to a mixer with a good VU or LCD chain and notice how many more dB it takes for the clean sound to seem equal in volume.

 

[fdeck]

So the amps ability to perform is in no way compromised by being pushed out of operational tolerances?

Which would be different from just reproducing a waveform, right?



Joe.

Right.

The graceful handling of clipping waveforms is carefully designed into any high quality musical instrument or pro-audio power amp. Thus, it's not really outside of the operational tolerances. Running practically any amp continuously beyond its rated sinewave power will cause thermal shutdown, especially amps rated at above a few hundred watts. But again, being able to survive this condition is part of a good design. And the amp will shut down just as quickly when it is driven to clipping, as when it is fed the same waveform externally.

The one thing to note is that like greenboy said, a distortion pedal doesn't necessarily put out the same waveform as a clipped solid state power amp. That's where the apples and oranges actually differ.

 

[Lowtonejoe]

But remains mistaken.

YEOWCH!



Joe.

 

[Lowtonejoe]

Well, it loses its ability to reproduce the waveform accurately, if that's what you mean.

Regardless, the bottom line is this: if you want to argue that amp clipping kills speakers and clean reproduction of a clipped signal *at the same amplitude* doesn't, then you have to explain why and how the content of the signal delivered to the speaker differs in the two cases, and if such a difference exists, why and how it should be harmful in one case. No one here has come close to doing that. If the speaker is being damaged in one case but not another, that means it has to be getting a quantitatively or qualitatively different signal in one case.

Again: try distorting a bass amp. Record that. Then feed that recorded signal through a much bigger, clean amp. Put both that signal and the original signal through speakers *at the same amplitude*. Presumably, if the recording was well done, the two signals should look almost identical. But in one case the amp is stressing and in the other it's not stressed at all; so by your logic one signal will damage the amp and the other won't. So explain why that should be so.

Richard, I would love to explain it to you...but I can't. I'm no engineer. Some people would even say I'm not intelligent...but I think they are just being mean.

There is without a doubt, IME, a direct correlation between solid state power amp clipping and speaker damage. I have talked to way too many guys over the years, end users and repairmen, to believe otherwise.

No matter how many scientific facts you throw at it, the correlation does not go away.

Maybe the problem is NOT clipping. Maybe the problem is something that happens WHILE clipping, hence, my comment about 'out of operational tolerences'. Maybe there is a mistake being made when we rate power amps and speakers. I dunno. Nevertheless, ss power amp clipping and speaker damage go hand in hand.

Sure, there are always exceptions. And no doubt with the right components you can instantly prove or disprove what I said. That's why all the proof in the world is absolutely meaningless (confounding?) when compared to real world experience.

Between your and Mark's badgering (educating, but don't tell him I said that) my faith in clipping being the sole culprit is shaken. However, when I consider all the accounts that I have heard from so many people that match my own, my suspicion of clipping, or what happens while clipping, reaches new heights.

I'm willing to accept a factual explanation but it has to match my, and so many others, experience.

Except for smart-alec remarks from others, ranging from faulty components to idiot repairmen to idiot end users, I haven't seen the right explanation yet.

See what I'm saying?



Joe.

 

[Lowtonejoe]

Right.

The graceful handling of clipping waveforms is carefully designed into any high quality musical instrument or pro-audio power amp. Thus, it's not really outside of the operational tolerances. Running practically any amp continuously beyond its rated sinewave power will cause thermal shutdown, especially amps rated at above a few hundred watts. But again, being able to survive this condition is part of a good design. And the amp will shut down just as quickly when it is driven to clipping, as when it is fed the same waveform externally.

...snip...

But I thought we were talking about the effect of clipping on the speaker?



Joe.

 

[Richard Lindsey]

Richard, I would love to explain it to you...but I can't. I'm no engineer. Some people would even say I'm not intelligent...but I think they are just being mean.

There is without a doubt, IME, a direct correlation between solid state power amp clipping and speaker damage. I have talked to way too many guys over the years, end users and repairmen, to believe otherwise.

No matter how many scientific facts you throw at it, the correlation does not go away.

Maybe the problem is NOT clipping. Maybe the problem is something that happens WHILE clipping, hence, my comment about 'out of operational tolerences'. Maybe there is a mistake being made when we rate power amps and speakers. I dunno. Nevertheless, ss power amp clipping and speaker damage go hand in hand.

Sure, there are always exceptions. And no doubt with the right components you can instantly prove or disprove what I said. That's why all the proof in the world is absolutely meaningless (confounding?) when compared to real world experience.

Between your and Mark's badgering (educating, but don't tell him I said that) my faith in clipping being the sole culprit is shaken. However, when I consider all the accounts that I have heard from so many people that match my own, my suspicion of clipping, or what happens while clipping, reaches new heights.

I'm willing to accept a factual explanation but it has to match my, and so many others, experience.

Except for smart-alec remarks from others, ranging from faulty components to idiot repairmen to idiot end users, I haven't seen the right explanation yet.

See what I'm saying?



Joe.

I think you've seen it but didn't recognize it.

In brief: it's not the clipping. It's something that sometimes happens during clipping but doesn't always happen and doesn't have to. It's also something that can happen entirely without clipping. It's overpowering or overexcursion, one or the other or both. Real world experience doesn't matter at all if you don't understand what's happening while you're experiencing it. Doesn't the fact that you can't explain it to me tell you something?

But before all this gets into some kind of toxic death spiral, I think I'll follow Mark's example and bow out. No hard feelings, just that I get the feeling we're covering the same ground over and over.

 

[The 0x]

[Invalid or Expired Link Removed]

 

[Lowtonejoe]

I think you've seen it but didn't recognize it.

In brief: it's not the clipping. It's something that sometimes happens during clipping but doesn't always happen and doesn't have to. It's also something that can happen entirely without clipping. It's overpowering or overexcursion, one or the other or both. Real world experience doesn't matter at all if you don't understand what's happening while you're experiencing it. Doesn't the fact that you can't explain it to me tell you something?

Of course. It tells me that I haven't heard a good enough explanation to dismiss the correlation and that I don't have the education to figure it out myself.

And sure, overexcursion and overpowering take out their share of cones.

But before all this gets into some kind of toxic death spiral, I think I'll follow Mark's example and bow out. No hard feelings, just that I get the feeling we're covering the same ground over and over.

O.k.

Later dude.



Joe.

 

[fdeck]

But I thought we were talking about the effect of clipping on the speaker?



Joe.

Yes, but the speaker just sees the waveform coming from the amplifier, so if you know how the amp is behaving, then you know what the speaker is experiencing.

 

[Lowtonejoe]

Yes, but the speaker just sees the waveform coming from the amplifier,

Yes.

so if you know how the amp is behaving, then you know what the speaker is experiencing.

Um...no.

You DO know what is being fed into the speaker but unless you are monitoring the speaker you DON'T know what it is experiencing. (That sounded weird. I don't think I've ever anthropomorphized a speaker before!)



Joe.

 

[fdeck]

True, but anything the speaker is experiencing that is not related to what is being fed in, is irrelevant to the issue of whether distortion causes speaker damage.

 

[Lowtonejoe]

True, but anything the speaker is experiencing that is not related to what is being fed in, is irrelevant to the issue of whether distortion causes speaker damage.

Yes, that is true.

Do cars perform better on regular or super gas?

A speaker is a linear motor.

When a SS power amp clips does the linear motor react identically to when it is fed an unclipped signal?

Over time?

What about the effect of temperature or physical stress to the motor?



Joe.

 

[Mark Reccord]

*Pokes head in for quick comment*

The clipping waveform you see shown in the 'explanations' isn't a very good representation of what the speaker 'sees' under clipping. The scope doesn't tell the whole story.

Get a tone generator. Set it to square wave, plug it into and amp and speaker and tell me if you hear a pure tone or not. That flat-topped waveform is really the fundamental frequency and a bunch of related harmonic frequencies summed together, very much like a note from an instrument. How many harmonics with significant energy there are above the fundamental dictate whether the clipping is 'hard' or 'soft' and is a function of amplifier design.

 

[Lowtonejoe]

*Pokes head in for quick comment*

The clipping waveform you see shown in the 'explanations' isn't a very good representation of what the speaker 'sees' under clipping. The scope doesn't tell the whole story.

Get a tone generator. Set it to square wave, plug it into and amp and speaker and tell me if you hear a pure tone or not. That flat-topped waveform is really the fundamental frequency and a bunch of related harmonic frequencies summed together, very much like a note from an instrument. How many harmonics with significant energy there are above the fundamental dictate whether the clipping is 'hard' or 'soft' and is a function of amplifier design.

Hmm....

/ponders



Joe.

 

[popinfresh]

I've been running power section distortion and preamp distortion for quite a while now.. No problems, except for tweeters.

 

[The 0x]

I've been running power section distortion and preamp distortion for quite a while now.. No problems, except for tweeters.

Ditto.


That must be loud as a trainwreck, though!