2. amps-preamps
  3. 160970-147909

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
pragmasi
212 posts
 
All amplifiers have a maximum and minimum output voltage, if this is exceeded then the amplifier should output dc (a constant voltage) until the signal comes back into range. So if you imagine a sine wave with the top and bottom cut off then that is what an ideal amplifier will produce when clipping (I'm talking solid state, valve amp distortion is more benign). A good designer will ensure an amplifier will enter and exit clipping in a controlled way (without oscillation etc.) although this is not always the case.
When designing an amplifier you can specify the maximum voltage and gain but you don't know what the level of the input signal will be. So if you take a consumer amplifier and provide a high level signal (most DACs put out a signal far higher than the nominal consumer level of +-0.447V) then the amplifier is in danger of clipping.
There are ways of limiting the gain at the extremes to try to avoid clipping but these distort the signal close to maximum output. Probably the best approach is some sort of warning light a red light or VU meter however they are rarely used in modern equipment.
twoleftears's avatar
twoleftears
5,318 posts
 
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.
teo_audio
2,197 posts
 
Just grab your amplifier’s keyboard, hit the tilde key, and then type in ’noclip’, hit enter...and bob’s yer uncle...
rodman99999
6,170 posts
 
@twoleftears -   There’s a decent treatise, under, ’Tone’, regarding tubes vs SS distortion, on this site: https://blog.thetubestore.com/tube-vs-solid-state-why-do-tubes-sound-better/#:~:text=The%20nature%20....       I've often attributed the more pleasant way tubes clip, as one reason some would think they're more powerful sounding, per rated Watt.      Not convinced that's the end of the story, however.
randym860's avatar
randym860
131 posts
 
Ok people make this more complicated than it needs to be. To make it more simple clipping is your amplifier trying to put out too much power. When you do this the distortion levels reach a point that can damage your speakers. You can damage 200 watt speakers with a 50 watt amp if you push the amp too far. Typically most amps will clip when they get to about 1% distortion. Amps with more headroom can exceed their rated power a little easier without clipping.
More to discover