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What is the sweet spot for WPC?

fill35u said:
Why does it have to be one or the other? Whether the conversation is friendly or not, or the problem is complex or not, have nothing to do with each other.

I get the feeling that you may eschew discussing technicalities as unpleasant. But what we've been pointing out to the OP for 11 pages now is that there are too many variables with too much effect to generalize.

I'd recommend to either measure or listen to see if a need exists for more power, or a possibility to get away with less power. Unfortunately, to get meaningful results from either approach requires certain levels of technical expertise- which if the OP already had, they probably wouldn't have asked the question in the first place. So the "friendliest" thing we can do is to educate them, to brace them against the perils of oversimplification. Including "upgrade-itis" and spending lots of money, which the OP specifically stated they wish to avoid.

I'm certainly not going to throw some nice round number out there, based on what appears to be the average situation of everybody on this site. The OP already mentioned a fairly typical range of power, they want to know if their particular situation merits change. Unfortunately, the problem is indeed complex, and the short answer we've been repeating has been "it depends".



Man, you got that right!
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It doesn't have to be one or the other. My point is that there is a huge difference between "shooting the breeze" with a group of guys that share a similar interest, speaking in generalities and expecting to receive generalized responses. This is a lot like socializing. Like this..."And I noticed that My Advent 5012s took a bit more juice to drive w/a 38WPC amp but that they seem very happy/easier to drive with a bit more power." Clearly, we are not entering a technical dialogue where it would be fitting to start talking about all the scientific aspects of setting up a system. If you think that's a relevant response, then go for it. I would love to read it. On one hand that would be akin to someone asking you "how are you" to which you respond..."This situation is complex and there is no short answer. I will need to get back to you with lab results for my recent blood work." No I don't find discussing technicalities unpleasant. Quite the contrary. But there is a time and place for them. Had the OP presented all of the relevant technical data regarding his situation then wanted feedback as to how to proceed, that would be one thing. But that's hardly the case. Without all the pertinent data, there is no real answer and we all get that. But that's not the point. In this case, the best answer is, in my opinion....keep it above a clean 100wpc and you will likely always be happy. And if you want to start to debate what "clean" is then you made my point for me.
 
Can somebody please explain what "clean watts" means? :dunno:
Does it come from people that play electric guitar?
Is it possible for "dirty watts" to sound better?
I really only see this term on AK, once in blue moon I will see it on another forum (usually not a regular poster).
 
I've been happiest pairing sensitive speakers with low power amplification. I'm not a call-the-cops listener and have no need to cover many hundreds of square feet with wall of sound. I'm currently listening to 91db/8ohm floorstanders driven by an 8wpc tube amp and have never been happier with the sound in my main rig. My end game will probably be something like a 12-15wpc el34 amp driving something like a pair of Klipsch heritage-family speakers.
 
opnly bafld said:
Can somebody please explain what "clean watts" means? :dunno:
Does it come from people that play electric guitar?
Is it possible for "dirty watts" to sound better?
I really only see this term on AK, once in blue moon I will see it on another forum (usually not a regular poster).
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I interpret "clean" as very low distortion...ie a spec such as...Total Harmonic Distortion: 0.012%....Frequency Response: 20hz to 20khz.....Power Output: 100 watts per channel into 8ohm stereo.

This would be an example of a "clean" 100wpc. Low distortion across the frequency range that is most important for music.

If you see watts referred to as clean here, this is probably what it means, although it also depends who is the one using the word.

With guitar, the concept is similar. The more distorted the signal the more dirty. The less distorted the signal, the cleaner.
 
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@z-adamson
Thank you.

That is what I assumed, but I've heard amplifiers (for audio) that have higher distortion that are more musical/natural sounding to my ears. In my use it would be redundant to use the term because it is assumed that we are not talking about an amp that is being overdriven (and thus becomes "dirty").
 
opnly bafld said:
@z-adamson
Thank you.

That is what I assumed, but I've heard amplifiers (for audio) that have higher distortion that are more musical/natural sounding to my ears. In my use it would be redundant to use the term because it is assumed that we are not talking about an amp that is being overdriven (and thus becomes "dirty").
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What would be an example of a solid state, home audio, hifi amplifier that has high THD yet sounds more musical than it's low THD counterparts?
 
opnly bafld said:
Can somebody please explain what "clean watts" means? :dunno:
Does it come from people that play electric guitar?
Is it possible for "dirty watts" to sound better?
I really only see this term on AK, once in blue moon I will see it on another forum (usually not a regular poster).
Click to expand...
I have no idea how it is quantified but one knows what it means when you hear it. I've heard some really good sounding units with distortion specs much higher than some thin sounding units with much lower distortion specs, speakers not with standing. I don't know what measures it but I know it when I hear it.
 
opnly bafld said:
What is high THD?
0.1%?
1%?
higher?
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You guys bandy about "THD" like you can describe the distortion spectra and behavior of an amp with a single number. Another case of drastic oversimplification that makes merely "shooting the breeze" pointless.

For that matter, what the heck is "musical" or "natural"? Plenty of musical instruments and natural phenomena have very high distortions. In fact, the closest thing to a completely "distortion free" musical note is the pure sine wave generated by an electronic synthesizer... And even if we judge sound quality subjectively, there's going to be enough differences in taste to make "musical/natural" evaluations an exercise in futility.

A power amplifier has one job, to accurately amplify the signal at its input. Start with that, and if you want to flavor to taste (or compensate for imperfections elsewhere in the chain), stick a "niceness" knob on the front to play with (and a switch to disable it!).

Power amplifiers for sound *reproduction* are *not* musical instruments. If yours starts acting like one, then you may indeed need some more WPC.
 
fill35u said:
You guys bandy about "THD" like you can describe the distortion spectra and behavior of an amp with a single number.
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You are oversimplifying things. We were not only talking about THD....we were talking about frequency response, power output into 8ohms stereo AND total harmonic distortion.
 
fill35u said:
Power amplifiers for sound *reproduction* are *not* musical instruments. If yours starts acting like one, then you may indeed need some more WPC.
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This is basically how I feel.

I prefer that they be transparent rather than imparting their own character, the way that most folk want a guitar amp to behave.
 
z-adamson said:
Since you said that you have heard "amps with higher distortion that sound more musical"...it would be up to YOU to explain what you meant by "higher THD", not me.
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It's been evident for quite a few years now based on psycho acoustic evaluations that it's not just the quantity of distortion, but the type of distortion that matters. In essence, high levels of even order (e.g. 2nd, 4th) distortion, even when audible, are quite tolerable and actually enjoyable. High order odd harmonics, such as 9th, are detectable at even very low levels, and degrade the sound. There are reasons for this, but to encapsulate it's all about the non-linear response of the auditory system and "masking" that occurs. 9th order harmonics can be detectable, by trained listeners, at levels of 0.05% or even lower, according to some studies.
This is, alas, exactly at the point where amplifiers that employ negative feedback often are problematic- especially those that are bipolar based. This is due to three mechanisms- the non-linearity of the amplifier output stage (so called crossover distortion), the non-linearity of the input stage that processes the feedback, and the low levels of corrective feedback that both increases the signal applied to the input (both musical input and feedback signals)- creating more distortion- and reduces the amount of correction that can be applied.
In addition, high frequency non-linearities that are not captured by the usual 1kHz THD spec can cause intermodulation of complex signals like music and degrade the effective S/N ratio, leading to a loss of resolution and clarity.
These are probably the two principal reasons why relatively high distortion open loop designs sound more transparent and pleasant than the more common moderate global feedback designs that are customarily employed.
Very high levels of broadband negative feedback or complex feedback/feedforward designs can overcome these limitations and produce ultra low distortion, very neutral sounding, amplifiers.
So, amps that have "low" THD measured at 1kHz can sound terrible, while those that measure much worse can sound far better.
 
z-adamson said:
I interpret "clean" as very low distortion...ie a spec such as...Total Harmonic Distortion: 0.012%....Frequency Response: 20hz to 20khz.....Power Output: 100 watts per channel into 8ohm stereo.

This would be an example of a "clean" 100wpc. Low distortion across the frequency range that is most important for music.
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Congratulations, you've just described 95% of "100 watt" solid state amplifiers ever made (if you move the decimal point to the left one number).

Can you hear the difference between 0.012 and 0.12?

z-adamson said:
You are oversimplifying things. We were not only talking about THD....we were talking about frequency response, power output into 8ohms stereo AND total harmonic distortion.
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What does fr and power (100 watt amplifier that clips at 5 watts o_O) have to do with "clean"?

z-adamson said:
This is basically how I feel.

I prefer that they be transparent rather than imparting their own character, the way that most folk want a guitar amp to behave.
Click to expand...

How do you know an amplifier is "transparent"? Numbers on a test sheet? :dunno:
 
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opnly bafld said:
Congratulations, you've just described 95% of "100 watt" solid state amplifiers ever made (if you move the decimal point to the left one number).

Can you hear the difference between 0.012 and 0.12?



What does fr and power (100 watt amplifier that only does 5 watts at clipping? o_O) have to do with "clean"?



How do you know an amplifier is "transparent"? Number on a test sheet? :dunno:
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See above post.
Yes, you can test for transparency, but almost nobody does.
It's called a many tone intermodulation test. In essence you apply many tones- tens to hundreds- to the input of an amp and measure the SINAD- effectively the ratio of the total output signal power to the total "noise" (unwanted signal) of the output. Modern test methodologies can mask the desired output signal and measure the residue.
The many tones emulate complex music signals and can be weighted, if you wish, to have a 1/f spectrum to more closely match that of music. They can also have a presence at ultrasonic frequencies allowing for the evaluation of any IM "folding" back into the audio band. That folding does exist in many amplifiers and can be a real problem.
Speakers, cables etc. have never been demonstrated to cause such effects that I am aware of.
If a constant input vs, frequency signal is employed the envelope shows the frequency response of the amp, and if the measurement is performed at the speaker termination it will show the entirety of the performance of the amplification system, including the cabling.
 
I have performed many tone tests on my system, extending the tones out to 48kHz, and obtained a SINAD of (if I remember correctly) 108dB (0.0004%) at a point just where the clipping warning lights come on with the AHB2s.
 
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