Still confused about clipping after reading all the articles.


From what I read, I understand what’s happening when the amp is clipping and the subsequent square wave form that could cause heat issues for voice coils. What I don’t understand is why would an amp allow itself to consume more power than it could handle in the first place.

1. More specifically, in the integrated amp scenario (amp with a volume control), let’s say you’re using a max power 80w integrated amp to drive a 87db@1w@1m speaker, if you turn up the volume on that amp, would it just max out at roughly the speaker playing 105db and it would not go louder - how could clipping happen then? Meaning the integrated amp should not throw a signal at itself stronger than it could handle?

2. For stand alone amp, I get that the input signal is not really under control of the amp and is more or less fed by the preamp so clipping could happen when the pre-amp is throwing big signals, but why wouldn’t the amp try to reject the signal the moment it senses clipping to protect the speaker?

3. Another related confusion is, how is it possible that sometimes I see powered active speakers blown because it’s trying to play too loud? Would it be true that the amp in those active speaker should always be designed to operate within the limit of its power handling? Could active speakers (say your Macbook speaker or iPhone speaker) enter clipping? I’ve never seen blown MacBook speakers even though people play at max volume all the time.

4. Could the source material itself be encoded to cause clipping? Let’s say a malicious sound mixer create a song with super quite music to force listener to turn the volume all the way up, but then there is a sudden loud noise encoded, would this push the amp into clipping?

5. Lastly, let’s say a speaker can handle 150w of power, and the speaker amp can output a maximum of 150w of power, even if the amp clips, does it mean it won’t damage the speaker? Could amp that’s rated at 150w per channel deliver much more than 150w in transient?

I might completely misunderstand some concepts here. But want to get some clarity.

bwang29

Showing 2 responses by twoleftears

My understanding is that SS and tube amps, generally speaking, tend to behave rather differently.  Distortion will increase just a little until the SS amp reaches its limit, at which point distortion tends to skyrocket.  Whereas tube amps will have rather more distortion gradually increasing over their standard operating range, but there is less of an "elbow" when clipping ensues.  Is that about right?

It's been suggested to me that this is one reason why people say that tube watt ratings are not the same as SS watts.
The graphs in Atkinson's measurements of amps in Stereophile are quite helpful.  He pushes amps to their limit, and you can see the line heading skyward in the graph where it goes into clipping.  He also specifies % of distortion allowed to measure maximum watt output, a % figure that he tends to relax with tube amps.