How diligently people reveal here what practical experience they have, or don't have;-) First do, then answer!
We can talk about your DBLTs afterwards.
As always: diy audio
It may even not be appropriate, but it doesn't change my point.
That's just to introduce the point, it doesn't really matter.
It's just to say that by observing the flow of water in a stream I will never be able to quantify its capacity in liters per second.
So my "human" assessment can never be compared with a measurement made by an instrument designed specifically to measure the flow of a stream.
So why ask such a thing to our hearing?
It's already quite obvious that it will never be able to do it and even if it did we would never know and it would still be pointed out as unreliable, unreliable and unrepeatable.
Even if there were (and there is not) a machine that could infallibly judge the SQ of a device, I would have to try it in my system before buying it, right?
So I'll always have to try before buying that device in my system, even if 99% of the participants in the double-blind listening panel agreed on the perceptual sensation.
So?
Why do those tests?
we all know that the thd, power, figures is almost irrelevant.
We can measure the thd in the loudspeakers output, we can measure thd with a amp connected to a loudspeaker.
We can also feed a signal which looks like music and see exactly the output at the speaker terminals.
This will show you why some amp sound aggressive etc.
It can take months for the ear to judge and much material of music until you know if you can hear some detail, some hidden sounds, if the sound is fatiguing or too mellow.
It is not one session that will reveal this, like your favorite drink that you sip for years...
We can measure the thd in the loudspeakers output, we can measure thd with a amp connected to a loudspeaker.
We can also feed a signal which looks like music and see exactly the output at the speaker terminals.
This will show you why some amp sound aggressive etc.
It can take months for the ear to judge and much material of music until you know if you can hear some detail, some hidden sounds, if the sound is fatiguing or too mellow.
It is not one session that will reveal this, like your favorite drink that you sip for years...
Yes, it is always advisable to hear whether it plays together, swings together;-)
A good hi-fi store will give its equipment to people to test at home.
But I have also had other experiences. There is one sound category that must be fulfilled, but is very rarely available for purchase: cleanliness.
I've had a few experiences: being invited to hi-fi freaks' homes who put everything else in their booths, with all the pipapo and whistles and DSPs and whatnot. They were never happy and were always searching and trying. So I should look over their problems. Most of the time I had a small box with no lid, the cables peeking out at random, just one capacitor visible, a small half-wave unbalanced PP amplifier inside, puny, barely visible, no 5 watts - "No high end" I said;-)
And then at some point I plugged it in and said, let's just listen to the music and then we'll see. And while we listened to music suddenly the tears started rolling;-) And not just once;-)
It is also possible to test the quality of devices in other ways. There are some recordings that most of them can't handle. For example, this one: I don't know of a single purchasable push-pull device that can handle it. And most of the devices developed here in the forum are replicas of well-known, supposed audio amps...-(
A good hi-fi store will give its equipment to people to test at home.
But I have also had other experiences. There is one sound category that must be fulfilled, but is very rarely available for purchase: cleanliness.
I've had a few experiences: being invited to hi-fi freaks' homes who put everything else in their booths, with all the pipapo and whistles and DSPs and whatnot. They were never happy and were always searching and trying. So I should look over their problems. Most of the time I had a small box with no lid, the cables peeking out at random, just one capacitor visible, a small half-wave unbalanced PP amplifier inside, puny, barely visible, no 5 watts - "No high end" I said;-)
And then at some point I plugged it in and said, let's just listen to the music and then we'll see. And while we listened to music suddenly the tears started rolling;-) And not just once;-)
It is also possible to test the quality of devices in other ways. There are some recordings that most of them can't handle. For example, this one: I don't know of a single purchasable push-pull device that can handle it. And most of the devices developed here in the forum are replicas of well-known, supposed audio amps...-(
After number of posts, this thread belongs to The Lounge.
I did this cos as a commercial designer of gear, I wanted to find what to put in stuff for people to buy. I was under the naive impression that designing stuff that sounded good would get good reviews and sell well. 😊
I did ABC tests rather than ABX cos you got statistical significance much faster. There's only 33% chance of a result being pure guesswork ... unlike ABX which has 50%. If I repeated the ABC DBLT 3x and the same device was preferred each time (11% chance of guesswork), I would (and did) put money that this would sound good in your system too.
We also found stuff that sounded bad eg most (all?) Golden Pinnae amps, and most importantly, people who were deaf (give totally random results in DBLTs). Alas, many HiFi reviewers fall into this category. This is specially important today cos it is very difficult to hear something properly in a shop or try it out at home.
For these people, we told them loudly and clearly that our stuff was hand carved from Unobtainium and solid BS by virgins.
We were very successful with this dual approach for more than 2 decades.
If this isn't the result of a DBLT, may I suggest you put less importance to it compared to a description from one that is 😊
As I said, even the best true golden ears are prejudiced. But they have the ability to lip read gear ... even in the dark. 😊
Obviously, there is no need for DBLTs if your gear is hand carved from Unobtainium and solid BS ....
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Wanna tell us the results of YOUR listening tests removing the bootstrap cap from your JLH 10W Class A?
I confess I have never tried this though I've put the JLH 10W Class A through several DBLTs. Mea culpa, mea culpa, mea maxima culpa
Wanna post the circuit of this miracle device?
Can you post the link in another fashion? My browser says "not available".
It seems that you guessed wrong since my system is mid-level without any esoteric pieces or any pieces set up by self-styled salesmen to impress the unwary customer.
However, I really like how it sounds and as I said I've never analyzed the measurements provided by the manufacturer except for electrical compatibility reasons, if any.
I've never given importance to listening a new device in a system other than my own, in my way of seeing things it wouldn't make sense.
For me it is in my system that I must like or dislike any piece of audio equipment.
However, I've built more than one DIY preamp even of members of this forum because the expense was affordable and the benefit/risk ratio high, in my pre-evaluation, and the expected fun was great.
In fact, I had a lot of fun, I liked how they sounded in my system and I kept them quite a long time and I still have them, even if not currently in use.
For the same reason I wondered without yet getting an answer what the purpose of listening tests of any kind was.
Whatever the motivation that drives me to buy a new device, I must have the possibility of trying it first in my system, otherwise I give up the purchase looking for alternatives.
I can choose a whatever piece without even listening to it if price is not an issue and expectations are reasonably realistic.
Anyway, the process of choosing a new piece is another one of the things that is extremely fun for me.
Just read the JLH article from 1969 (When I was 12...)
"It would be convenient if the performance of an audio amplifier (or loudspeaker or any other similar piece of audio equipment) could be completely specified by frequency response and harmonic distortion characteristics. Unfortunately, it is not possible to simulate under laboratory conditions the complex loads or intricate waveform structures presented to the amplifier when a loudspeaker system is employed to reproduce the everyday sounds of speech and music; so that although the square wave and low-distortion sine wave oscillators, the oscilloscope, and the harmonic distortion analyser are valuable tools in the design of audio circuits, the ultimate test of the final design must be the critical judgment of the listener under the most carefully chosen conditions his facilities and environment allow. The possession of a good standard of reference is a great help in comparative trials of this nature, and the author has been fortunate in the possession, for many years, of a carefully and expensively built "Williamson" amplifier, the performance of which has proved, in listening trials, to equal or exceed, by greater or lesser margins, that of any other audio amplifier with which the author has been able to make comparisons."
Unfortunately I subscribed to "Popular Electronics" instead of "Wireless World" at the time, so I missed out. Built the "Lil Tiger" instead.
Not that it would have made much difference in my understanding; I'm sure the above paragraph would have flown right over my head.
"It would be convenient if the performance of an audio amplifier (or loudspeaker or any other similar piece of audio equipment) could be completely specified by frequency response and harmonic distortion characteristics. Unfortunately, it is not possible to simulate under laboratory conditions the complex loads or intricate waveform structures presented to the amplifier when a loudspeaker system is employed to reproduce the everyday sounds of speech and music; so that although the square wave and low-distortion sine wave oscillators, the oscilloscope, and the harmonic distortion analyser are valuable tools in the design of audio circuits, the ultimate test of the final design must be the critical judgment of the listener under the most carefully chosen conditions his facilities and environment allow. The possession of a good standard of reference is a great help in comparative trials of this nature, and the author has been fortunate in the possession, for many years, of a carefully and expensively built "Williamson" amplifier, the performance of which has proved, in listening trials, to equal or exceed, by greater or lesser margins, that of any other audio amplifier with which the author has been able to make comparisons."
Unfortunately I subscribed to "Popular Electronics" instead of "Wireless World" at the time, so I missed out. Built the "Lil Tiger" instead.
Not that it would have made much difference in my understanding; I'm sure the above paragraph would have flown right over my head.
Things have changed since 1969. A lot of science on perception vs measurements has been done. Also, a lot of psychology experiments, including many cognitive psychology experiments, have been conducted since then.
"Critical judgment of the listener" is deeply flawed, at least if we're talking about sighted trials. There're just too many confounding variables.
Those figures shouldn't be the only ones measured, though.
Tom
"Critical judgment of the listener" is deeply flawed, at least if we're talking about sighted trials. There're just too many confounding variables.
Do we, though? An amp with low THD is an amp that is closer to an ideal, Out = In * A, amplifier than one with high THD. A 0.1 W power amp will have trouble filling a reasonably sized living room with sound if used with most speakers. One that provides 100 W will have an easier time.
Those figures shouldn't be the only ones measured, though.
Tom
Design practices and measurements are objective tools which can be forgotten when the subjective listening tests begin.
So the measurements matter only temporarily.
High THD is going to be a problem.
Low THD is not going to be a problem, given that other characteristics are also good. And, that is the fly in the ointment.
In 1977 I bought a pair of Klipsch Heresy speakers and a Sony STR-5800-SD receiver (58W). My sister liked the sound of the system, but she and her husband were short of cash and opted for the Sony STR-2800 SD receiver (28W) instead, but bought the same Heresy speakers. Specs on both receivers were very similar with the exception of power out and input options.. In normal listening with the Heresy speakers peaks were only 1W (32mW average power) so both systems should have sounded good. The lower power receiver was disappointing compared to the higher power receiver. I still have the speakers, my granddaughter has the receiver. It still sounds great. I did have to replace a few caps, and do some solder touch up for annular ring solder cracks.
I tried finding the JHL 10W amplifier on evil-bay, and what they are selling does not look anything like the schematics posted. Too bad. Might have been fun to play with. JHL 10W amp
Low THD is not going to be a problem, given that other characteristics are also good. And, that is the fly in the ointment.
In 1977 I bought a pair of Klipsch Heresy speakers and a Sony STR-5800-SD receiver (58W). My sister liked the sound of the system, but she and her husband were short of cash and opted for the Sony STR-2800 SD receiver (28W) instead, but bought the same Heresy speakers. Specs on both receivers were very similar with the exception of power out and input options.. In normal listening with the Heresy speakers peaks were only 1W (32mW average power) so both systems should have sounded good. The lower power receiver was disappointing compared to the higher power receiver. I still have the speakers, my granddaughter has the receiver. It still sounds great. I did have to replace a few caps, and do some solder touch up for annular ring solder cracks.
I tried finding the JHL 10W amplifier on evil-bay, and what they are selling does not look anything like the schematics posted. Too bad. Might have been fun to play with. JHL 10W amp
knowing your ss has now over a thousand watts gives you expectations of better sound, it is more comforting that anything else.
I honestly expected them to sound the same considering how little power was used to drive the speakers, and the manufacturer of the receivers. I measured the power with my system when I had friends over for a gathering. Power level was such that one could carry on a conversation over the music. I listened to my sisters system much later, and it just didn't sound as good. It was a great disappointment to me. My expectation bias was such that they should have sounded identical.
This holds even for the best ears in my DBLTs. You can't work on something for months without being biased in its favour. That's why you have to check your prejudices in DBLTs.
I thought I'd answered that as a former designer & maker of stuff. Are you suggesting we don't do any kind of listening test? Or that we do tests with the $$ price tag prominently displayed?
Alas, not everyone is as lucky as you. Most people these days buy online and rely on probably deaf Reviewer's opinion.
I haven't tested everyone though I tested many, in 2 decades of DBLTs. I do have a good idea of how to tell da deaf wannabe Golden Pinnae though 😊
BTW, the JLH 10W Class A I tested used RCA TO-3 outputs. Can't remember whether these are supposed to have better clarity & definition than the later plastic devices 😲 Alas, my mains cables weren't hand carved from Unobtainium & solid BS by Virgins so my DBLTs are probably null & void
Yes, But. We still dont have a convenient box that one could, say, connect the equipment to and between A and B, automatically and definitively register which one most people would think "sounds better".
Given of course neither A nor B have some glaring flaw; each being in the upper echelon performance wise, according to the standard measurements JLH noted as the "valuable tools" in 1969 era amplifier design.
My guess is if anything ever does this as a "convenient box" it would be AI. And then you dont get to know how it did it and that will, of course, lead to suspicion of validity. I'm thinking of it independently determining / ratifying that TheGimp would prefer the STR-5800-SD to the STR-2800-SD, by feeding it two recordings of these amplifiers playing through the same Klipsch Heresy speaker set.
Have been building lots of amps, preamps, and phono stages the last 6 years and have adopted this approach: if the new box sounds better than the one it is replacing, in its goes and it is never measured -- only listened to. While it is certain that any build is going to have some inaccuracy, why inject knowledge of that information into your listening world?
Now, of course, all has to be carefully adjusted during the build so that the bias is correct, the SMDs (and Mosfets) are matched, the DC offset zeroed out, and on and on.
But why spoil your listening pleasure once the device is actively in use? I start them all out at 100% and, over a sufficient listening time, deduct when an audible issue becomes clear. Since I am a lifelong musician who plays real-world instruments daily, it is easy to identify any less-than-perfect qualities as they appear.
Have spent countless hours measuring rooms with REW (very helpful), maintaining and rebuilding tape and cassette machines (necessary), and designing and fine-tuning studio spaces. All have to be measured and analyzed. See clearly the need for measuring here.
But if you build it, why judge other than listening? For me, that would lessen the delight. And, of course, building your own equipment is a gas, right?
Now, of course, all has to be carefully adjusted during the build so that the bias is correct, the SMDs (and Mosfets) are matched, the DC offset zeroed out, and on and on.
But why spoil your listening pleasure once the device is actively in use? I start them all out at 100% and, over a sufficient listening time, deduct when an audible issue becomes clear. Since I am a lifelong musician who plays real-world instruments daily, it is easy to identify any less-than-perfect qualities as they appear.
Have spent countless hours measuring rooms with REW (very helpful), maintaining and rebuilding tape and cassette machines (necessary), and designing and fine-tuning studio spaces. All have to be measured and analyzed. See clearly the need for measuring here.
But if you build it, why judge other than listening? For me, that would lessen the delight. And, of course, building your own equipment is a gas, right?
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That’s an interesting experience. Have you tried your sister’s receiver in your home with your speakers? I wonder if the results might be more similar. I’m wondering if differing room acoustics might be in play.
Best.
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