Do more expensive amplifiers make a difference?

[pauln]

I'm not sure why you think a psychologist would be needed in order to conduct blind testing - what psychology is involved?

An engineer or technician would be needed to set up the test and to ensure it was carried out under controlled conditions. A mathematician would be needed to work out the statistical significance of the results. A psychologist? Please enlighten me.

I suggest that you will give no credence to those tests referred to by MakkaPakka because you don't like the results.

If you want to find out by means of blind testing whether people prefer amp A to amp B, you are, in effect, assessing people’s responses to a range of auditory stimuli. Testing of this kind is called sensory evaluation testing. It’s widely used in the food and cosmetics industries. Its scientific underpinning comes from a sub-discipline of psychology called psychophysics, i.e. the study of the relation between sensory stimuli and psychological responses. (Psychophysics was founded by the great German psychologist Gustav Theodor Fechner in the mid-19th century.)

Sensory evaluation testing involves a number of non-straightforward issues, including: how do you select participants? How do you prepare them for the tests? What questions do you ask them? How do you present the stimuli, e.g. in what context and for how long? How do you evaluate the results? A lot of thought goes into achieving a maximum of neutrality and catering for people's cognitive biases. (For instance, people will tend to react more strongly to the first of a pair of stimuli.)

So this is why psychology isn’t only relevant to blind testing of hi-fi; it’s the discipline that underpins any robust and successful testing.

You wouldn’t need a mathematician by the way, as any respectable undergrad degree in experimental psychology includes the study of statistics. I grant you would want an electrical engineer though, to ensure the equipment was working properly, levels were matched etc.

Matt

That's interesting and makes sense. I thought that it would be straightforward in that you would sit someone in a chair and ask them which was which - if the differences are so apparent (or night and day). Would that not count as a valid test then?

 

[matt49]

That's interesting and makes sense.

I'm glad that was helpful.

I thought that it would be straightforward in that you would sit someone in a chair and ask them which was which - if the differences are so apparent (or night and day). Would that not count as a valid test then?

It depends how robust you want your results to be. As I said in an earlier post, if you're happy for a psychologist to measure the performance of an amp, then you'll be happy for an engineer to conduct a blind test.

Matt

 

[pauln]

That's interesting and makes sense.

I'm glad that was helpful.

I thought that it would be straightforward in that you would sit someone in a chair and ask them which was which - if the differences are so apparent (or night and day). Would that not count as a valid test then?

It depends how robust you want your results to be. As I said in an earlier post, if you're happy for a psychologist to measure the performance of an amp, then you'll be happy for an engineer to conduct a blind test.

Matt

Just out of curiousity, how confident are you that you could "pass" a properly conducted abx test on two different amps? And how different would they have to be? Same conditions as the Harbeth challenge.

 

[pauln]

What I don't do is read what other people think, and then pedal it as fact.

I read what people have measured or what they know about the subject - I'm confident that Alan Shaw knows about speakers and electronics and so no, I don't feel that I am pedalling other peoples thoughts as facts at all. I just re-read my first post and actually, they are all my own thoughts, apart from the assertation that a Watt is a Watt. After that it's all been about countering other peoples arguments.

How do you learn if not by reading? Did you prove to yourself that the earth was round before you told your children it was? Newton wrote down his laws of motion we read them and we learn from them. He also backed things up with measurements and empirical observations, not subjective feelings.

 

[MakkaPakka]

It is illogical that if the differences are as big as some claim there's no actual evidence to back it up.

It is easy to explain why a speaker or record player will sound different from another but there doesn't seem to be any explanation of how and why an (adequately powered) amp will sound different other than an assumption that better components are used so it must sound better.

'Well I heard it' is completely redundant because I could pull up 'evidence' of that kind about all sorts of snake oil products that cannot possibly work.

I have a completely open mind on the subject but not so open I'm willing to throw money around without some justification.

 

[CnoEvil]

How do you learn if not by reading?

You can learn by watching, practicing, experiencing, simulating and doing.

The problem with confining it solely to reading, is that one is naturally drawn to the viewpoint that most closely aligns itself with one's own beliefs, and concentrate on that......giving the alternative POV little more than a cursory glance.

Until you go out and listen to a whole variety of kit at different prices, the only opinion you can realistically give, is that of others.....it just depends on who you choose to believe.

The sole purpose of a hifi is the replication of music, which is in itself, a subjective experience.....by trying to reduce it to a set of measurements misses the point imo.

 

[John Duncan]

pauln, you seem to think that it is a trivial exercise to produce an amplifier that is a 'straight line with gain' and therefore any deviation from must be the manufacturer 'messing with the sound'?

 

[pauln]

Until you go out and listen to a whole variety of kit at different prices, the only opinion you can realistically give, is that of others.....it just depends on who you choose to believe.

As I've already said, I have done. Did you really think I've not listened to anything? Did you not read my post where I said why I'd changed my opinion about HiFi?

 

[CnoEvil]

'Well I heard it' is completely redundant because I could pull up 'evidence' of that kind about all sorts of snake oil products that cannot possibly work.

......as is, "I haven't heard it, but someone on a forum says so."

IMO. Until people realize that it's all subjective ie. from what you hear, to what you like and to what value you put on any perceived gain.......and so this can only be ascertained by finding one's own path and set of rules.

 

[pauln]

pauln, you seem to think that it is a trivial exercise to produce an amplifier that is a 'straight line with gain' and therefore any deviation from must be the manufacturer 'messing with the sound'?

Did you read the rest of the post?

You want to cherry pick one phrase out of 4 or 5 paragraphs and use it out of context to give a completely different impression of what I said?

Wonderful.

 

[MakkaPakka]

this can only be ascertained by finding one's own path and set of rules.

Either there is a difference or there is not. The answer is, universally, either yes or no.

 

[CnoEvil]

this can only be ascertained by finding one's own path and set of rules.

Either there is a difference or there is not. The answer is, universally, either yes or no.

Your logic is unshakable......now getting agreement on the difference................ :wall:

 

[CnoEvil]

Until you go out and listen to a whole variety of kit at different prices, the only opinion you can realistically give, is that of others.....it just depends on who you choose to believe.

As I've already said, I have done. Did you really think I've not listened to anything? Did you not read my post where I said why I'd changed my opinion about HiFi?

If you have heard Valve, Hybrid, Class A , AB, B or D amps in a variety of price ranges, up to high end, then you are right; but the impression you give is that you have only heard a handful of amps.......which is btw, not meant to be in any way condescending, or indeed as any sort of criticism.

It's just that I believe that meaningful statements are problematical unless they come from personal experience.

 

[MakkaPakka]

You've jumped ahead to the point where a difference has been established. I'm still stuck on the start line waiting for some evidence or a reasonably compelling argument of the difference.

As I said on my first post in the thread - I want to believe! Someone please persuade me so I can go shopping guilt-free in the knowledge I'm actually going to be achieving an upgrade.

 

[altruistic.lemon]

Until you go out and listen to a whole variety of kit at different prices, the only opinion you can realistically give, is that of others.....it just depends on who you choose to believe.

As I've already said, I have done. Did you really think I've not listened to anything? Did you not read my post where I said why I'd changed my opinion about HiFi?

If you have heard Valve, Hybrid, Class A , AB, B or D amps in a variety of price ranges, up to high end, then you are right; but the impression you give is that you have only heard a handful of amps.......which is btw, not meant to be in any way condescending, or indeed as any sort of criticism.

It's just that I believe that meaningful statements are problematical unless they come from personal experience.

Measurements do count, you know, CNO, they explain what you hear. I don't think, having heard a lot of amps, that differences are that great, certainly far less than turntable/cartridge combinations and way less than speakers. You need a powerful amp for lots of speakers, but, other than that, you'd be pushing to hear differences in any form of blind testing, irrespective of price.

 

[CnoEvil]

Measurements do count, you know, CNO, they explain what you hear. I don't think, having heard a lot of amps, that differences are that great, certainly far less than turntable/cartridge combinations and way less than speakers. You need a powerful amp for lots of speakers, but, other than that, you'd be pushing to hear differences in any form of blind testing, irrespective of price.

Of course measurements count, but they are not the "be all and end all" of what you may like.....you're a knowledgeable Bod, so you probably agree to some extent.

The natural tendancy is for people to want a "quick fix," as it saves putting the work in.

 

[CnoEvil]

As I said on my first post in the thread - I want to believe! Someone please persuade me so I can go shopping guilt-free in the knowledge I'm actually going to be achieving an upgrade.

I have spent most of my posts in this thread explaining that imo nobody can do this.....but if you want someone to tell you it is worth upgrading, then "the right choice of amp, that is suitable for your system, is worth upgrading to." :shifty:

 

[matt49]

Just out of curiousity, how confident are you that you could "pass" a properly conducted abx test on two different amps? And how different would they have to be? Same conditions as the Harbeth challenge.

I can’t remember the terms of the Harbeth challenge, I’m afraid.

As for a properly conducted blind test, whilst I do profess (literally) to know quite a bit about some aspects of psychology, sensory evaluation testing is something I only know about in fairly general terms, so anything I said about the specifics of such a test would be misleading. Sorry if that sounds like a cop out, but it's important to be honest.

Having said that, I doubt very much whether I could reliably distinguish between a range of amps of the same design (e.g. Class A, Class A/B, valve …) at different price points. Based on my experience thus far, I think it’s more likely I could distinguish between amps of different design.

On an unrelated (or perhaps related?) subject, I can pretty reliably distinguish between different types of wine. I’ve done many blind tastings and have a fairly good hit rate at determining which grape variety a wine’s made from and where it’s made (though there are many, many people who are far better at it than I am). My point is: success is based on experience accumulated over years of tasting wine. The more blind tastings of wine you do, the better you get at it. You can learn and be taught to be a good blind taster. Differences that are invisible to a beginner are often glaringly obvious to someone with long experience.

As far as hi-fi's concerned I'm not in that category.

Matt

 

[lindsayt]

It is illogical that if the differences are as big as some claim there's no actual evidence to back it up.

It is easy to explain why a speaker or record player will sound different from another but there doesn't seem to be any explanation of how and why an (adequately powered) amp will sound different other than an assumption that better components are used so it must sound better.

'Well I heard it' is completely redundant because I could pull up 'evidence' of that kind about all sorts of snake oil products that cannot possibly work.

I have a completely open mind on the subject but not so open I'm willing to throw money around without some justification.

A SET valve amp uses different devices to a transistorised amp to actually amplify the signal. They will also have different circuits through which the signal travels.

Having said that, through high efficiency speakers, two well executed amps from each genre can sound more similar than dissimilar to each other. With inefficient, difficult to drive speakers at generous volumes, but still below clipping on the SET amp, you are likely to notice bigger differences between the amps, especially with bass transients.

SET vs transistorised is an extreme example of different circuits and amplification devices, but even amongst solid state amps you will still get circuit differences and differences in the transistors used.

 

[davedotco]

SETs are probably not the best examples to use in any amplifier comparison.

The biggest issue is the generally high output impedance that causes all but the simplest of loudspeakers to modify the amplifiers frequency response to degrees that would nomally be considered unacceptable in any other amplifier.

Probably more sensible to use push-pull, either triode or pentode. In the original quad challenge, Peter Walker set up the 8 watt II amplifier, the 30 watt 303 and the 100 watt 405, driving ELS57s at 'normal' levels and no one could tell the difference.

That is valve push-pull, class AB and the current dumper, all very different designs.

 

[Covenanter]

Until you go out and listen to a whole variety of kit at different prices, the only opinion you can realistically give, is that of others.....it just depends on who you choose to believe.

As I've already said, I have done. Did you really think I've not listened to anything? Did you not read my post where I said why I'd changed my opinion about HiFi?

If you have heard Valve, Hybrid, Class A , AB, B or D amps in a variety of price ranges, up to high end, then you are right; but the impression you give is that you have only heard a handful of amps.......which is btw, not meant to be in any way condescending, or indeed as any sort of criticism.

It's just that I believe that meaningful statements are problematical unless they come from personal experience.

My problem with this is that it assumes that personal subjective opinion actually has real value! I doubt that anybody, and I mean anybody, has a good enough aural memory to allow meaningful subjective comparisons to be made. Moreover other external factors affect subjective opinions very greatly. For example my hifi sounds better (to me!) in the mornings than in the afternoons. I don't know why this is but I am confident that it has nothing to do with the system and everything to do with me and my environment.

Chris

 

[busb]

You've jumped ahead to the point where a difference has been established. I'm still stuck on the start line waiting for some evidence or a reasonably compelling argument of the difference.

As I said on my first post in the thread - I want to believe! Someone please persuade me so I can go shopping guilt-free in the knowledge I'm actually going to be achieving an upgrade.

Armed with the knowledge that all amps either sound identical or near enough that ABX testing won't show any differences, I don't understand your dilemma. It's simple: you either believe that adequately conducted ABX testing methodology works or it doesn't - I'm not entirely convinced personally. That may mean that I'm merely trying to support my world view on the subject, of course. However, if it can be shown that ABX testing is foolproof, I can take SQ out of the equation & consider the manufacturer's repution, build quality versus cost, looks & specification without further ado. That leaves a great number of people duped by an entire industry aided & abetted by magazines & websites. One could use te same criteria to judge if God exists or not: belief versus evidence.

The reasons I'm not entirely convinced are twofold. Firstly, ABX relies on short-term memory that's pretty unreliable, near-instantaneous switching nonwithstanding. Secondly, the methodology doesn't seem to compensate for false negatives to the same degree it does for positive ones - any test should show up any participants with either poor or damaged hearing either temporary or permanent. If you countenance the idea that forewarned is forearmed, why not borrow a supposedly better amplifier for a week - at least you can then evaluate if you are personally prone to audio mythology or not.

 

[busb]

As for a wattt being a watt being a watt. It is true but.. a watt is a vector product of two other quantities equaling a third such as V x I, I squared x R etc so a very simple relationship (with DC but not so with AC such as audio waveforms). This gives a linear relationship until we hit the ceiling of maximum current. Some amps will notionally provide the same wattage until the dynamic load of a loudspeaker dips towards zero impedance at certain frequencies, where the current fails to follow that nice straight line!

 

[BernardLanguillier]

I had the chance to compare a few months ago a mid end 20 years old Yamaha amp to a Marantz PM6004 (or something approaching)... and the difference was extremely obvious, to the extend that the owner of the system (that includes an excellent pair of speakers) immediately heard the difference before knowing I had replace the amp.

It will show more or less depending on the quality of the material being played and of the other components in the set up though.

I have been improving my system over the last 10 years with a main focus on amplification. Going from a home teatre Denon integrated mid end, to a high end Rotel stero amp, separate Nuforce 9 Ref V3 and now D-Premier. And the differences are very clear with each evolution but they do not always manifest themselves on the same metric. Using the example of the D-Premier, it brought breakthough improvements in terms of clarity, transparency, fluidity and resolution. The Nuforce had delivered improvement in terms of bass power and fluidity,...

With the Devialet, my former pair of B&W 804s revealed its true potential with the speakers turning out to be an amazing performer while even the excellent Nuforce separates had never managed to make them sing convincingly. Those are not supposed to be such a challenging load.

Cheers,
Bernard

 

[CnoEvil]

My problem with this is that it assumes that personal subjective opinion actually has real value!

Chris

It only has real (meaningful) value to the person holding it, which is my point. If I gave you 6 sets of measurements from 6 different amps and told you to pick the one you would prefer, without listening....you would have a 1 in 6 chance of getting it right, as imo. you can't tell exactly how an amp will sound by looking at measurements.

You are a classical music lover, and I would be very surprised if you could measure the subtle things that cause you to like one performance over another....and it is these same things that I personally look to see if a system can convey..