Watt nonsense!

[twiiii]

Most of the music I listen to is classically based, with some big band Jazz and some smaller group jazz. All the recordings have anywhere from 30 to 50 db dynamic range whether on a DG or Sheffield LP for instance or well produced CD. . Big band Jazz can be vary widely depending on the label. Verve and Reprise and especially Command can have very large dynamic ranges. Small group jazz such as a trio or featuring a singer not near as much usually. So some times I'll be listening at normal 6 watts for fairly loud and then a peak will come along pushing just a bit over 100 watts. Thats why I have amps rated at 500watts more less.

The HT speakers are 7 db more efficient so 2 watts is about it most of the time. But put on the right DVD and 120 watts is no problem at all.

 

[rothwellaudio]

The negative effects of clipping are generally accepted and are not in dispute. This discussion should only be concerned with sonic differences amplifiers when driven within their operational limits.

I agree. There seems to be a commonly held belief that any 50 watt amp is pretty much the same as any other 50 watt amp, and that any 100 watt amp is exactly the same as a 50 watt amp except it has 3dB more headroom. If that was the case it would be entirely appropriate to focus on calculations regarding speaker sensitivity, listening distance and maximum SPLs, and a more powerful amplifier would always be preferable to a less powerful amplifier, but I don't believe things are that simple. Some amplifiers are capable of maintaining control and revealing all the subtle details in a recording whereas others seem to turn everything into a raucous din, and that's long before the clipping limit is reached.

 

[Snow]

I place zero stock in subjective listening comparisons in any situation in which the listener is aware of which amplifier is playing - or for that matter, any audio component.

So if that were the case and you were given 4 amps and had a choice of which one you liked the best to keep how would you choose? Have a friend come by and change them out without you knowing which was which or what? and how would you know if you brought one home to see if it sounded better then what you had currently? Perhaps I missed your point here?


Regards Snow

 

[ejman]

I agree. There seems to be a commonly held belief that any 50 watt amp is pretty much the same as any other 50 watt amp, and that any 100 watt amp is exactly the same as a 50 watt amp except it has 3dB more headroom. If that was the case it would be entirely appropriate to focus on calculations regarding speaker sensitivity, listening distance and maximum SPLs, and a more powerful amplifier would always be preferable to a less powerful amplifier, but I don't believe things are that simple. Some amplifiers are capable of maintaining control and revealing all the subtle details in a recording whereas others seem to turn everything into a raucous din, and that's long before the clipping limit is reached.

Many moons ago I read an article in a magazine (remember Hi-Fi magazines?) that ran a detailed blind study of about a dozen amplifiers at all kinds of price levels and topologies with an "audiophile" audience. The conclusion from that study if I remember correctly was that all amplifiers sound the same as long as they are not clipping. It actually took me some years to get over that and what finally did it is that I realized that I had started listening less and less to my music as I had purchased generic super low distortion amps. It just became kind of annoying sonic wallpaper. Fortunately I'm enjoying and paying attention to my music very much these days. I think we are fortunate to live in the best of times Hi-Fi wise ( except for some of the prices!)

 

[izeek11]

O.K. Let's try this step by step.
Point No1. - (and probably the most important) - Remember that high fidelity sound reproduction is more about quality then quantity - you are not running a PA system in your living room. Refer back to the old adage - the most important watt is the first one.

You power ration of 10:1 is probably about right. How loud a system goes is as much about the efficiency of the loudspeakers as the maximum output power of an amplifier. Input sensitivity will also play a major part in this as will amplifier gain factor You will see an output power rating in watts and an input sensitivity in millivolts (mV). Low efficiency loudspeakers require far more input power to produce the same audible sound level as a high efficiency loudspeaker. Again you 10:1 ratio applies.
example:
Amplifier A - Input sensitivity 250mV for full output of 50watts.into an 8 ohm load.
Amplifier B - Input sensitivity 500mV for full output of 100 watts into an 8 ohm load.

I you feed both these machines with a 200mV signal, amp A will probably produce about 40watts, amp B will probably produce about the same. look at the relationship between input sensitivity and output power in each case.

CD players do tend to have a higher output than most other sources. There is no advantage in trying to increase the output of other devices. They are what they are and largely you have to live wit this.

Headroom. You run a hi-fi amp at a relatively low average power level. I have a rule of thumb that says 'If you need to run an amp at above 50% volume setting it's not big enough'.
If you are running a music signal at a reasonable power level and a loud transient occurs in the music (a load bass drum or similar), although the average power level is hardly affected, the amplifier will be required to draw a large current for a very short period to enable the output voltage to correctly follow that transient. That ability to draw extra current for a very short period without clipping is called 'headroom' and it's also where your 10:1 power to volume ratio applies.

I hope this helps to at least start to answer you questions. This is just skimming the surface as I have tried not to be too technical for you.

i like that.

 

[Snow]

Many moons ago I read an article in a magazine (remember Hi-Fi magazines?) that ran a detailed blind study of about a dozen amplifiers at all kinds of price levels and topologies with an "audiophile" audience. The conclusion from that study if I remember correctly was that all amplifiers sound the same as long as they are not clipping. It actually took me some years to get over that and what finally did it is that I realized that I had started listening less and less to my music as I had purchased generic super low distortion amps. It just became kind of annoying sonic wallpaper. Fortunately I'm enjoying and paying attention to my music very much these days. I think we are fortunate to live in the best of times Hi-Fi wise ( except for some of the prices!)

I don't believe that, I really don't care what magazine said what unless you have some sort of hearing problems that you cant determine a difference in the sound between 12 totally different amps, now you may not be able to pick out which amp is which but certainly anyone with halfway decent hearing should be able to hear a difference. Just because someone wrote something in a magazine or online does not make it so.

 

[ejman]

I don't believe that, I really don't care what magazine said what unless you have some sort of hearing problems that you cant determine a difference in the sound between 12 totally different amps, now you may not be able to pick out which amp is which but certainly anyone with halfway decent hearing should be able to hear a difference. Just because someone wrote something in a magazine or online does not make it so.

I actually agree with you. I guess I just expressed myself poorly as usual.

 

[izeek11]

when i had a 70 and 110 avr, my gear sounded pretty good i thought.
because they were inexpensive in a manner of speaking, i bought a 150 wpc amp.(actually wound up with three.)
the difference was really ear-opening for me. as others have described hearing things in tracks they hadnt noticed before.
and the fullness at low volume.
and when you need a big bang or some, this amp is a beast.
not because of volume but maybe presentation, soundstage, dynamics, and face it, power in a piece. that bass drum just flat kicks.
i have jbl l890s. they dont even begin to breathe until you get about 70-75db.
on the very few occasions i get past 85-90db, they just do the damn job.
none of that happened with avr/rcvrs for me.
some people own 5.0s even when they drive in the city mostly. same principle. nice to have that ooomph when you want it.

 

[Snow]

I actually agree with you. I guess I just expressed myself poorly as usual.

No worries I am just happy you are back to listening and enjoying your music.

Regards Snow

 

[HPMguy]

That first watt is most important because the vast majority of your listening (at least at reasonable SPL levels) is in that first watt. Bias is set at idle, you should have as close to zero crossover distortion as is possible to get with it set correctly.

If that first watt produces poor sound, it's not gonna get better with more power, just louder. If you have crossover distortion at 1 watt, how could it be less at 10 or 20 or 50 watts on the same amp? It's not power dependent, the offset will still be there. It might be smaller proportional to the height of the signal, but it will NOT go away and I don't see how the effects would vanish either.

 

[ejman]

That first watt is most important because the vast majority of your listening (at least at reasonable SPL levels) is in that first watt. Bias is set at idle, you should have as close to zero crossover distortion as is possible to get with it set correctly.

If that first watt produces poor sound, it's not gonna get better with more power, just louder. If you have crossover distortion at 1 watt, how could it be less at 10 or 20 or 50 watts on the same amp? It's not power dependent, the offset will still be there. It might be smaller proportional to the height of the signal, but it will NOT go away and I don't see how the effects would vanish either.

Many of the distortion curves I have seen for solid state power amps show higher distortion at the start of the curve at less than I watt, decreasing as they get to one watt and then staying low until the amp runs out of gas and gets close to clipping. If most of our listening with reasonable efficiency speakers is at less than 1 watt wouldn't the higher distortion at < 1 watt levels have an impact?

 

[rothwellaudio]

Bias is set at idle, you should have as close to zero crossover distortion as is possible to get with it set correctly.

I agree that crossover distortion is a significant factor in sound quality. One problem is that it isn't simple to set, being dependent on temperature. It's difficult for the bias circuit to track the temperature of the output devices, hence people saying their amp sounds better after it's been on for an hour (or whatever).

 

[62caddy]

So if that were the case and you were given 4 amps and had a choice of which one you liked the best to keep how would you choose? Have a friend come by and change them out without you knowing which was which or what? and how would you know if you brought one home to see if it sounded better then what you had currently? Perhaps I missed your point here?


Regards Snow

I I had to select one blindly without knowing a thing about any of them, I would have them sent out be professionally tested and measured. That would be the only way to know for certain what I was getting.

 

[TerryS]

Many of the distortion curves I have seen for solid state power amps show higher distortion at the start of the curve at less than I watt, decreasing as they get to one watt and then staying low until the amp runs out of gas and gets close to clipping. If most of our listening with reasonable efficiency speakers is at less than 1 watt wouldn't the higher distortion at < 1 watt levels have an impact?

The rise in the the distortion curve below 1 watt is the effect of noise. Those curves show Total Harmonic Distortion + Noise. At low levels the noise component becomes more significant and starts to dominate the measurement. What you are seeing is the constant noise level becoming a higher percentage of the measurement as the signal level becomes smaller.

 

[rothwellaudio]

The rise in the the distortion curve below 1 watt is the effect of noise. Those curves show Total Harmonic Distortion + Noise. At low levels the noise component becomes more significant and starts to dominate the measurement. What you are seeing is the constant noise level becoming a higher percentage of the measurement as the signal level becomes smaller.

So crossover distortion is completely eliminated? I don't think that can be assumed.
https://www.eetimes.com/distortion-in-power-amplifiers-part-iv-the-power-amplifier-stages/

 

[TerryS]

So crossover distortion is completely eliminated? I don't think that can be assumed.
https://www.eetimes.com/distortion-in-power-amplifiers-part-iv-the-power-amplifier-stages/

Yes. At very low levels the amp is basically a class A amp. If an amp had zero distortion, only noise, then the THD+N % plot would be a straight line that was an extension of that straight portion below 1 watt. It’s a plot of a constant noise level as a percentage of a decreasing signal. Simple math.

 

[rothwellaudio]

Yes. At very low levels the amp is basically a class A amp. If an amp had zero distortion, only noise, then the THD+N % plot would be a straight line that was an extension of that straight portion below 1 watt. It’s a plot of a constant noise level as a percentage of a decreasing signal. Simple math.

Eh? So you are saying that crossover distortion doesn't exist? Or not?

 

[sberger]

I've owned some pretty powerful amps but I'm done with them. These days, in my medium space, I enjoy McIntosh tube amps that are rated (conservatively) at between 25-40 watts, and I use them to drive speakers that are notoriously inefficient. These include AR3's, Allison One's, and Bozak 302's. While I hold no dispute with those that sprout the party line that those speakers are best used with amps that offer much more current and watts then my Mc's, for the music and listening levels that I prefer, those speakers sound fantastic to me with those amps. I've tried larger amps with all of them, and yes the sound is different, but simply not as engaging to me as the Mc's.

So once again it's a matter of taste, and everybody should use their own ears to decide on what works best for them.

 

[toddalin]

Many moons ago I read an article in a magazine (remember Hi-Fi magazines?) that ran a detailed blind study of about a dozen amplifiers at all kinds of price levels and topologies with an "audiophile" audience. The conclusion from that study if I remember correctly was that all amplifiers sound the same as long as they are not clipping. It actually took me some years to get over that and what finally did it is that I realized that I had started listening less and less to my music as I had purchased generic super low distortion amps. It just became kind of annoying sonic wallpaper. Fortunately I'm enjoying and paying attention to my music very much these days. I think we are fortunate to live in the best of times Hi-Fi wise ( except for some of the prices!)

The problem is the way tests were done. Unless you can instantaneously A/B/C/D/... the amps just to hear ANY difference, through all kinds of different speakers, this would be the expected result because of the ear's poor memory for very subtle changes.

The way to get around this would be to record the results of all of the amps, all playing the same pieces at the same volume level with all other conditions the same, in the highest definition/resolution format currently available and A/B/C/D/... the recordings for ANY differences.

I mean, after all..., don't all microphones sound "the same" if played through a poor system???



BTW, pay attention to 4:15 on.

 

[62caddy]

Many moons ago I read an article in a magazine (remember Hi-Fi magazines?) that ran a detailed blind study of about a dozen amplifiers at all kinds of price levels and topologies with an "audiophile" audience. The conclusion from that study if I remember correctly was that all amplifiers sound the same as long as they are not clipping. It actually took me some years to get over that and what finally did it is that I realized that I had started listening less and less to my music as I had purchased generic super low distortion amps. It just became kind of annoying sonic wallpaper. Fortunately I'm enjoying and paying attention to my music very much these days. I think we are fortunate to live in the best of times Hi-Fi wise ( except for some of the prices!)

One of the best articles ever to appear in a major hi fi magazine. Written in a time when the audio press actually had the journalistic integrity to speak the truth. The article made the case - compellingly & credibly - that differences in performance between various amplifier is likely to be imperceptible among a wide variety of listeners. To my knowledge, there has never been a study credibly showing statistically significant audible differences between competently designed amplifiers that are operated within their design limits. I'm truly saddened to hear that you "got over it". meaning that you have allowed yourself to betray your own reason in order to go along with some popular/cliquish narrative.

The following quote by Bertrand Russell sums up the situation perfectly-

The fact that an opinion has been widely held is no evidence whatsoever that it is not utterly absurd. Indeed, in view of the silliness of the majority of mankind, a widely spread belief is more likely to be foolish than sensible."