What makes a high end audio amp "better" then a low end unit?

[AndyC_772]

In amp, and speaker choice, as for listening and evaluating, unless you have medical hearing loss, many of us can tell the difference, it's just that we don't know how to do so, so, we end up buying what pleases us most.

I don't understand that whole way of thinking when it comes to hi-fi.

My audio equipment exists for one reason, and one reason alone: to make sound that pleases me.

It's not a scientific instrument. I've no requirement for the sound in my room to be objectively, quantifiably, as similar to some hypothetical "original" sound as possible. I just want to enjoy listening to it.

The "original" sound is a total fallacy anyway. Unless the recorded content happens to be a live performance, it's probably a construction fabricated in a studio with the objective of sounding pleasing to the ear when reproduced through (usually fairly crappy) equipment.

since you don't know the what original instruments supposed to sound like

I don't care. Big difference!

Last year I treated myself to a new system. I figured I'd reached the time in my life when I'm old enough to be able to afford the hi-fi I've always wanted, but not so old that my ears are worn out and can't appreciate it.

I spent ages in various hi-fi shops, with a variety of familiar music, and came away with strong opinions of most of the kit I heard. The differences were anything but subtle; speakers in particular each have their own character, and surprisingly few had me wanting to go back for another listen.

I don't doubt that they'd all measure well, but that's not what I'm spending good money for. I want to enjoy the music. Nothing else!

In the end I bought a system from Arcam and Spendor, plus an exceptionally capable subwoofer from a small Norwegian outfit called Arendal Sound. The amp contains a DSP which can analyse the room characteristics and pre-process the signal to correct both the frequency and impulse responses at the listening position. For movies it's great, though I prefer the sound with it off for music.

[Buriedcode]

I do love these threads.  I'll admit, I have never designed a commercial amplifier, nor do I own any expensive amps, speakers or systems, I'm quite happy with my phone, my PC, or a raspberry-pi-based-portable player. 

But I follow these threads to see a whole range of views and nuggets of info about analogue design, only to see it (almost...) descend into a pissing match about who has the better ears, who has the best gear.  What makes a 'high end' amp better than a 'low end' ?  Depends on how you define "high end" and "low end".  Depends on Power, features, reliability, cost, who you're trying to impress, how justified you feel in spending the cost of the amp, the general volume one listens to music... the brand name, warranty.  In fact actual 'sound' must be way down the list..

[Audioguru]

Good amplifiers have a very low output impedance for a good damping factor. Then the resistance of the cable between the amp and the speaker also must be low. Then the speaker sounds "tight" and follows the voltage output from the amplifier.
A poor damping factor results in the speaker resonating something like a one note bongo drum that sounds bad.

Nobody mentioned the power supply? A cheap power supply has resistance that allows an amplifier to produce high momentary low distortion power called "music power" before its voltage and power output sag. When the voltage and power sag then the amplifier clips high output peaks that sounds bad.

[BrianHG]

And the balance setting, what is it for? 

I don't have a balance setting.  It's a stupid idea unless you are deliberately trying to correct for junky setup where some of the cheapest equipment today should be beyond the need of such correction.

[Cliff Matthews]

And the balance setting, what is it for? 

I don't have a balance setting.  It's a stupid idea unless you are deliberately trying to correct for junky setup where some of the cheapest equipment today should be beyond the need of such correction.

My NAD 3020 has no balance either. I've had it ~35 years and re-capped it once. Just some 2N3055's and MJ2955's designed by some Swedish guy and fabbed in Korea in believe.. FWIW, I mentioned Nelson Pass because a high-end shop nearby talks of him but sells Mark Levinson products looking more like military tanks than amps.. funny world this.

[DrGeoff]

Linearity, low noise and a stable power supply.

[innkeeper]

everything is great on paper until you throw a reactive load in the mix with varying rectance at various frequencies and varying phase shifts and room responses.
how an amp reacts is as varied as the number of amp and speaker combinations you can put together.

Gotta pitty people who is chasing that unreachable goal of the ultimate realistic sound.  and even if they find it, it will be the ultimate sound only to him/her.

it is a huge rabbit hole. and there is no bottom. and why there will always be room for one more power amplifier

one thing i've seen to moving in a direction for a somewhat modern approach is individually amplified drivers that are compensated for via a dsp and room monitoring.
shit gets crazy!

[Fungus]

one thing i've seen to moving in a direction for a somewhat modern approach is individually amplified drivers that are compensated for via a dsp and room monitoring.

Yep. This is more likely to be the future (IMHO) than spending a lot of money on amplifiers.

how an amp reacts is as varied as the number of amp and speaker combinations you can put together.

For this reason.

Well, if you are OK with a crap sound, there is indeed no need  . Fortunately for manufacturers of that crap the majority of consumers don't give a #**! about the sound quality. Especially as it is "scientifically proven" that it does not matter.  And so it goes. I am quite happy to be in a minority who cares about quality sound.

I'm sure there's a point in there somewhere but no actual facts were presented, it's all Ad Hominem. 

Facts:

Is there a massive sound difference between a high-end 1970's amp and a high-end 2017 amp? No, not really.

Are all electronic parts better/cheaper/smaller/easier-to-get today than in the 1970s? Yes. Massively so.

Nobody's saying you can build an amp for $10 (which is what will be in a consumer grade HiFi) but the days of exotic $10,000+ amplifiers are long gone.

[IanMacdonald]

We all know that if we apply for example a square wave to a partially inductive load, the current will not be a square wave.
But the displacement of the membrane tends to follow the current's value.
There is therefore a weakness of the transistor amplifier on this point.

The tube amplifier behaves more like a current source, in particular because of its low rate of feedback and its high internal impedance. (low damping factor)

Either type could be made to give a constant current output. The problem with doing so is what happens at the speaker's resonant frequency. At that point both efficiency and impedance increase drastically. With constant voltage drive those effects cancel out to a large extent. With constant current drive the delivered power would actually increase as well as the efficiency, leading to a massive 'bass boom' problem.
 

[oldway]

It is exactly on this principle (massive bass boom) that loudspeakers type bass reflex are based.
They are tuned to the resonance frequency to boost these bass and recover them to add to the sound from the front of the speaker membrane.

C. A. Briggs, in his book "The Loudspeakers" recommends the plane baffles rather than the bass reflex.
Ideally, the plane baffle should have an infinite area, which is of course impossible .... It recommends to mount the speaker (s) in a wall, it is what looks the most like an infinite plan baffle.

If a closed loudspeaker is used, it must have the largest possible volume.

Regarding the resonance frequency of the speaker, it is attenuated in a closed speaker by the absorbent material that is inside .... In addition, there are many electronic means to suppress resonance (filters, graphic equalizer), and the sensitivity of the ear is reduced in the very low frequencies ....

There are no reasons to avoid current drive of the speakers.....

[Fungus]

Regarding the resonance frequency of the speaker, it is attenuated in a closed speaker by the absorbent material that is inside ....

They're also usually made of chipboard/mdf instead of fancy wood.

It's not the manufacturers being cheapskates, those "woods" resonate less than the real thing.

[David Hess]

I have always wanted to make my own amp that was compareable to a macintosh amp for a fraction of the price but what exactly makes it better?

Ultimately I think amplifier quality is in most cases just another case of marketing triumphing over engineering.  But there are lots of engineering factors which affect quality.

1. How much was it derated for operating at its worst case output power?  This impacts reliability and operating life.  Commercial designs tend to be much better than consumer designs in this respect which is expected.
2. Is it a simple or complex class-AB design?  At high frequencies the former might produce 0.1% THD while the later produces 0.001% or better.  I am always struck by how simple class-AB designs literally duplicate the simplified schematic for an early 3 stage operational amplifier.
3. How does it perform (or fail) under adverse operating conditions like a 2 ohms load or output short?
4. How well does it recover from clipping?  Tube amplifiers have a natural advantage here do to their softer saturation characteristics but some solid state designs are truly horrible in this regard for reasons having nothing to do with saturation.
5. Does it protect the speakers against amplifier failure?

Bob Cordell's book Designing Audio Power Amplifiers gives a great overview of simple versus complex designs and the attention to detail necessary for a high quality design.

The thing which puzzles me is why poor designs are produced when most of the cost is in the output transistors and power supply that could be the same in a low or high quality design.  This might simply be do to diminishing returns, poor source material, and low customer expectations.

First of all, there are no legal standards against which audio amps are measured.

In the US there has been since 1974:

https://www.ftc.gov/enforcement/rules/rulemaking-regulatory-reform-proceedings/amplifier-rule

Nowadays they make Class-D amplifiers with a single chip (digial input) 100+W output and <0.01% THD+N.  I dont even understand why there are amplifiers anymore. Seems so pointless. I believe that good quality active speakers are the way to go.

That level of distortion is typical for a good but simple class-AB design.

Yep. Class D has come on in leaps and bounds over the last decade. All the old class A and AB stuff is pretty much obsolete.

Modern MOSFETs mean class D amps can be amazingly efficient. Tiny sub-$10 chips can power big powerful systems with almost zero THD.

eg. http://www.ti.com/product/TPA3255/datasheet

So yeah, amplifier problem is solved. Look at speakers and room acoustics instead.

I notice that TI leaves intermodulation out of their datasheet and how does it respond to clipping?  The other specifications do not strike me as particularly outstanding compared to a complex class-AB design.  The efficiency is nice of course.

I agree that the amplifier problem is solved but only in the sense that the speaker problem is solved.  In both cases most consumer examples are mediocre but with the loudness wars, that is good enough.

It is exactly on this principle (massive bass boom) that loudspeakers type bass reflex are based.
They are tuned to the resonance frequency to boost these bass and recover them to add to the sound from the front of the speaker membrane.

If they are tuned properly, then the result is not "massive bass boom" but extended low frequency response, a second order low frequency roll off, and lower impedance at resonance.  The last is important because minimizing the cone movement minimizes intermodulation distortion which otherwise makes deep base sound boomy and indistinct.  Some people of course like that sound but I place them into the same class of people who like the loud hiss from harmonic distortion, indistinct vocals, and excessive compression from the loudness wars.

In a practical setting, the lower intermodulation distortion means being able to turn the volume up to shake the room and contents without sounding loud.

They're also usually made of chipboard/mdf instead of fancy wood.

It's not the manufacturers being cheapskates, those "woods" resonate less than the real thing.

But they are rarely heavy enough.  On the other hand, most consumers would prefer speakers they can lift easily.  I am somewhat amused when I find old bookshelf speakers which weight more than modern but cheap floor speakers.

[Beamin]

I can hear the difference in 0.8THD and 0.03% with decent speakers. I don't think most people could though. I stay away from anything over 0.1% THD because you are not getting the full benefit of your speakers.

I very much doubt that. With a decent pair of headphones, you stand a chance, but not much, especially at your age.

What is my age? Do you knw why I bought a higher end amp and not a the  cheapest end amp or highest end? Because the ones cheaper then it didn't sound as good. The ones abouve it didn't sound any better but still better then the cheaper ones with the exception of Bose who has no mid bass or base. Once again how do you know that? Or are you just being contrary because you can't tell the difference and if you can't tell nobody can? High end speakers sound better then high end head phones. Why do you say that?

Here is a very easy way to tell if an amp will sound good or not when I worked in an electronics store as a kid: Pick up the amp; is one side or corner of it really heavy? If yes that because it has a great big transformer in it and all the cheap amps feel light. Transformers are full of copper which costs a lot of money. Probably the most expensive part of a cheap amp and probably tied with the cost of transistor pairs with the build cost of an expensive amp.

That might have been true for older amplifier designs, which still use a big lump of iron to convert the mains voltage to DC, but not in modern designs, which use a switched mode power supply.

[Zero999]

I can hear the difference in 0.8THD and 0.03% with decent speakers. I don't think most people could though. I stay away from anything over 0.1% THD because you are not getting the full benefit of your speakers.

I very much doubt that. With a decent pair of headphones, you stand a chance, but not much, especially at your age.

What is my age? Do you knw why I bought a higher end amp and not a the  cheapest end amp or highest end? Because the ones cheaper then it didn't sound as good. The ones abouve it didn't sound any better but still better then the cheaper ones with the exception of Bose who has no mid bass or base. Once again how do you know that? Or are you just being contrary because you can't tell the difference and if you can't tell nobody can? High end speakers sound better then high end head phones. Why do you say that?

I don't know your exact age but, going from your other posts, I know you're not young, therefore you will have some age-related hearing loss, especially at high frequencies.

Did you subject yourself to a double blind listing test? I highly doubt it. Cognitive bias, aesthetics, size, cost,  can easily explain differences in perceived sound quality. No one is immune to this. The only way to be sure one can tell the difference is a double blind test, repeated enough times.

Headphones generally sound better than speakers, even cheap headphones vs high end speakers, because the ear is in the near field region, rather than the far field so it's easier to get a flat frequency response and reflections and absorption due to room acoustics are no longer factors.

[Alex Nikitin]

Did you subject yourself to a double blind listing test? I highly doubt it. Cognitive bias, aesthetics, size, cost,  can easily explain differences in perceived sound quality. No one is immune to this. The only way to be sure one can tell the difference is a double blind test, repeated enough times.

 

It should read:

The only way to be sure no one can tell the difference is a double blind test, repeated enough times. Blind tests is the biggest con in audio, forget all these poor snake oil cable purveyors .

Cheers

Alex

[Zero999]

Did you subject yourself to a double blind listing test? I highly doubt it. Cognitive bias, aesthetics, size, cost,  can easily explain differences in perceived sound quality. No one is immune to this. The only way to be sure one can tell the difference is a double blind test, repeated enough times.

 

It should read:

The only way to be sure no one can tell the difference is a double blind test, repeated enough times. Blind tests is the biggest con in audio, forget all these poor snake oil cable purveyors .

Cheers

Alex

What are you saying?

Double blind tests are how it's done in medicine and other fields. They are the only way to prove there is an actual detectable difference, in something, other than cognitive bias and placebo!

Oh sarcasm doesn't always get through the interweb very well. Yes, mustn't let science get in the way of these poor people.

[Alex Nikitin]

Did you subject yourself to a double blind listing test? I highly doubt it. Cognitive bias, aesthetics, size, cost,  can easily explain differences in perceived sound quality. No one is immune to this. The only way to be sure one can tell the difference is a double blind test, repeated enough times.

 

It should read:

The only way to be sure no one can tell the difference is a double blind test, repeated enough times. Blind tests is the biggest con in audio, forget all these poor snake oil cable purveyors .

Cheers

Alex

What are you saying?

Double blind tests are how it's done in medicine and other fields. They are the only way to prove there is an actual detectable difference, in something, other than cognitive bias and placebo!

Oh sarcasm doesn't always get through the interweb very well. Yes, mustn't let science get in the way of these poor people.

If you would like my opinion on blind tests in audio, have a look at my messages in that thread. I don't like repeating what I've already expressed elsewhere.

Cheers

Alex

[Beamin]

I can hear the difference in 0.8THD and 0.03% with decent speakers. I don't think most people could though. I stay away from anything over 0.1% THD because you are not getting the full benefit of your speakers.

I very much doubt that. With a decent pair of headphones, you stand a chance, but not much, especially at your age.

What is my age? Do you knw why I bought a higher end amp and not a the  cheapest end amp or highest end? Because the ones cheaper then it didn't sound as good. The ones abouve it didn't sound any better but still better then the cheaper ones with the exception of Bose who has no mid bass or base. Once again how do you know that? Or are you just being contrary because you can't tell the difference and if you can't tell nobody can? High end speakers sound better then high end head phones. Why do you say that?

I don't know your exact age but, going from your other posts, I know you're not young, therefore you will have some age-related hearing loss, especially at high frequencies.

Did you subject yourself to a double blind listing test? I highly doubt it. Cognitive bias, aesthetics, size, cost,  can easily explain differences in perceived sound quality. No one is immune to this. The only way to be sure one can tell the difference is a double blind test, repeated enough times.

Headphones generally sound better than speakers, even cheap headphones vs high end speakers, because the ear is in the near field region, rather than the far field so it's easier to get a flat frequency response and reflections and absorption due to room acoustics are no longer factors.

Yes  next time I go to the speaker store I will hire scientists do set up a double blind placebo test with psychologists and statisticians to make sure the scientists have ruled out any hidden variables. This way it will ensure that my subjective taste in a 100% subjective matter is 100% sterilized and devoid of any emotional bias. I might end up getting a set that sound horrible to me but at least they were scientifically proven to be better. I will also have them build an anechoic chamber that is nothing like the room I will be using them in. Of course before I do any of this I will have an audiologist test my hearing to find out what I'm sensitive to when analyze the data from the acoustic scientists also to rule out hidden bias.

Do you ever think "Hey what I just wrote was completely ridiculous and would make no sense to the average ( a technically minded but practical) person reading it and is also TOTALLY impractical and would never happen".

Double blind placebo tests to go speaker shopping? Really? REALLY?
Totally ridiculous is an understatement and you are kind of embarrassing yourself especially if you start making replies doubling down on why your post is not ridiculous.. 

You buy what sounds good to you even if you are victim of audio phoolerly they still are what sounds good and you enjoy it.

[coppice]

Did you subject yourself to a double blind listing test? I highly doubt it. Cognitive bias, aesthetics, size, cost,  can easily explain differences in perceived sound quality. No one is immune to this. The only way to be sure one can tell the difference is a double blind test, repeated enough times.

 

It should read:

The only way to be sure no one can tell the difference is a double blind test, repeated enough times. Blind tests is the biggest con in audio, forget all these poor snake oil cable purveyors .

Cheers

Alex

What are you saying?

Double blind tests are how it's done in medicine and other fields. They are the only way to prove there is an actual detectable difference, in something, other than cognitive bias and placebo!

Oh sarcasm doesn't always get through the interweb very well. Yes, mustn't let science get in the way of these poor people.

If you would like my opinion on blind tests in audio, have a look at my messages in that thread. I don't like repeating what I've already expressed elsewhere.

Cheers

Alex

If you want to argue that many double blind tests are unreasonable, because they are not well constructed to highlight the things they are supposed to be looking for, I'm sure you will get a lot of agreement from others here. If you are arguing that some dodgy double blind tests mean double blind tests are not a good thing (which is what I take from what you have written), then you aren't going to get much positive feedback from a science/engineering literate audience.

If what you actually mean is much better double blind tests are needed, then highlight the weaknesses in current methods, and how things could be improved.

[Alex Nikitin]

If you want to argue that many double blind tests are unreasonable, because they are not well constructed to highlight the things they are supposed to be looking for, I'm sure you will get a lot of agreement from others here. If you are arguing that some dodgy double blind tests mean double blind tests are not a good thing (which is what I take from what you have written), then you aren't going to get much positive feedback from a science/engineering literate audience.

If what you actually mean is much better double blind tests are needed, then highlight the weaknesses in current methods, and how things could be improved.

For all practical purposes in Hi-Fi audio double blind tests are a complete waste of time (and that is what science should be telling us). Somewhere, at the end of a rainbow, a useful audio DBT (very expensive and extremely difficult to set up, no doubt) may exist, however I am not wasting my time looking for that unicorn either. I wish I could have tests and methods which would be useful for a valid definition of sound quality, but so far I've discovered none which could give better results than a simple subjective listening test with all its drawbacks (as much as I hate to admit it, as an engineer). Yes, there is always a good chance to fool yourself, but at least there is also a good chance to do your job properly and make audio equipment that is enjoyable to listen to.

Cheers

Alex

[xani]

Did you subject yourself to a double blind listing test? I highly doubt it. Cognitive bias, aesthetics, size, cost,  can easily explain differences in perceived sound quality. No one is immune to this. The only way to be sure one can tell the difference is a double blind test, repeated enough times.

 

It should read:

The only way to be sure no one can tell the difference is a double blind test, repeated enough times. Blind tests is the biggest con in audio, forget all these poor snake oil cable purveyors .

Cheers

Alex

What are you saying?

Double blind tests are how it's done in medicine and other fields. They are the only way to prove there is an actual detectable difference, in something, other than cognitive bias and placebo!

Oh sarcasm doesn't always get through the interweb very well. Yes, mustn't let science get in the way of these poor people.

He's our resident audiophool, just ignore him.

[Gyro]

On the contrary, he is a experienced engineer and respected contributor to this forum. 

[Zero999]

I can hear the difference in 0.8THD and 0.03% with decent speakers. I don't think most people could though. I stay away from anything over 0.1% THD because you are not getting the full benefit of your speakers.

I very much doubt that. With a decent pair of headphones, you stand a chance, but not much, especially at your age.

What is my age? Do you knw why I bought a higher end amp and not a the  cheapest end amp or highest end? Because the ones cheaper then it didn't sound as good. The ones abouve it didn't sound any better but still better then the cheaper ones with the exception of Bose who has no mid bass or base. Once again how do you know that? Or are you just being contrary because you can't tell the difference and if you can't tell nobody can? High end speakers sound better then high end head phones. Why do you say that?

I don't know your exact age but, going from your other posts, I know you're not young, therefore you will have some age-related hearing loss, especially at high frequencies.

Did you subject yourself to a double blind listing test? I highly doubt it. Cognitive bias, aesthetics, size, cost,  can easily explain differences in perceived sound quality. No one is immune to this. The only way to be sure one can tell the difference is a double blind test, repeated enough times.

Headphones generally sound better than speakers, even cheap headphones vs high end speakers, because the ear is in the near field region, rather than the far field so it's easier to get a flat frequency response and reflections and absorption due to room acoustics are no longer factors.

Yes  next time I go to the speaker store I will hire scientists do set up a double blind placebo test with psychologists and statisticians to make sure the scientists have ruled out any hidden variables. This way it will ensure that my subjective taste in a 100% subjective matter is 100% sterilized and devoid of any emotional bias. I might end up getting a set that sound horrible to me but at least they were scientifically proven to be better. I will also have them build an anechoic chamber that is nothing like the room I will be using them in. Of course before I do any of this I will have an audiologist test my hearing to find out what I'm sensitive to when analyze the data from the acoustic scientists also to rule out hidden bias.

Do you ever think "Hey what I just wrote was completely ridiculous and would make no sense to the average ( a technically minded but practical) person reading it and is also TOTALLY impractical and would never happen".

Double blind placebo tests to go speaker shopping? Really? REALLY?
Totally ridiculous is an understatement and you are kind of embarrassing yourself especially if you start making replies doubling down on why your post is not ridiculous.. 

You buy what sounds good to you even if you are victim of audio phoolerly they still are what sounds good and you enjoy it.

There is no need for that attitude.

None of what you've said is scientific. It's all highly subjective. You can't be sure that you can actually tell the difference between 0.8% and 0.03% THD, because you've not proven you can.

I thought we were talking about amplifiers not speakers? Suppose two amplifiers, set to exactly the same volume, playing the same music, were connected to a pair of speakers, via a relay, to switch between the two amplifiers, controlled randomly by a computer. If you can tell which amplifier is driving the speakers, significantly beyond 50% of the time, then you've proven that the two amplifiers actually sound different to you. Whether or not you prefer the one with the better figures, is up to you.

Obviously you can't perform the test mentioned above in a Hi-Fi store and I never suggested it was, which was the point I was trying to make. You have many other factors, other than sound waves from the speakers, which influence your judgement, whether you like it or not. Some of these factors are important, when considering a purchase: aesthetics, ergonomics, build quality etc. but if you think you're basing your decision on sound quality, then you're kidding yourself. Someone else posted a very good video on the subject, but I can't find it.

Fortunately, modern, well-designed solid state amplifiers, are audibly transparent, i.e. no one will be able to tell the difference between them, in the above scenario, as long as they're not overdriven.

[Alex Nikitin]

Fortunately, modern, well-designed solid state amplifiers, are audibly transparent, i.e. no one will be able to tell the difference between them, in the above scenario, as long as they're not overdriven.

"you're kidding yourself"  .

Cheers

Alex

[nfmax]

Back in 1978...

http://www.keith-snook.info/wireless-world-magazine/Wireless-World-1978/Valves%20versus%20Transistors%20DCD.pdf

None of which negates the audiophile's subjective judgment that the music sounds better when played through a system of which he (and for some reason, it almost always is a he) approves. Whether it's the class A, the no feedback, the polished mahogany case, the oxygen free copper or the warm feeling that comes from being able to afford it in the first place, it really does sound better! High-end audio is a fashion business: provided some minimum standard of technical performance is met (and sometimes not even then) the numbers don't really count.

And the enjoyment of music is, after all, a subjective thing.