John Curl's Blowtorch preamplifier part III

[mountainman bob]

I now believe Earl Geddes may have been right about the 95% thing. I used to believe a greater percentage of people could hear small aberrations in sound reproduction (at a conscious level), but I have reluctantly come to doubt it. I do think we probably have more than a random share of five percent'ers (or whatever the actual number is) here at diyaudio. Many or most appear to be looking for better sound quality on a limited or even very limited budget (I have poor people in India for example, trying to make better dacs, and I am trying to help them diy it). Unfortunately, most of the people here wanting better sound quality don't understand enough about electronics to know how to figure out what is actually causing their small-ish but audible (to some) SQ problems. There are a few real engineers around here willing to help constructively, but not enough, and most seem to have the good sense to avoid Blowtorch. I should probably try harder to ignore the bait myself, but the intolerance for perceptive listeners can be hard to let stand.

Anyway, I'm am feeling better today now recovering from what was likely a little food poisoning. Even better, I have been told I should have an AK4499 board here in about a week We will see if it happens on time or not.

.

Thanks Mark,

Well that pretty much describes my POV,

Being told everything sounds the same when designed within a given set of parameters is insulting, then being told the differences I do hear are bias or imaginary certainly borders on ignorance.

I suppose being in a 5% minority (if that is the case) will never result in a commercially viable yet affordable(mid fi) option.

So I suppose the next logical step is diy (mainly why I’m here in the first place)
But like mark points out my electronics experience (although better than the average man on the street) is nowhere near enough to design/build anything better.

So I suppose recognizing my inabilities is a step in the right direction.....that being said I’m highly interested in this AK 4499 project,
how much $$ would it take to build or if too complicated buy into it?

It’s quite obvious to me I’m one of these 5%’ers.....is there a club?

Maybe we need our own forum section!

Bob

 

[mmerrill99]

.........
It’s quite obvious to me I’m one of these 5%’ers.....is there a club?

Maybe we need our own forum section!

Bob

Put on your flame-proof cape - I sense incoming
I believe the excerpt of Chris post I quoted sums up the 95% "I don't care"
Most don't care because they find sound/music is not that important to care about. Others are negatively biased so that they do not care to be open about what they hear. And finally, there may be some who really do not register better sound.

fMRi may well sort out those groups & show what actually is registered & what is being denied but it will take a lot of research to be able to tease this out ?

 

[Jakob2]

Semantics, hardly profound. The inference is clear to most.

I don't understand, can you state which part of the issue you don't understand?

It doesn't seem to be important so I give it a rest.

 

[mountainman bob]

Put on your flame-proof cape - I sense incoming
I believe the excerpt of Chris post I quoted sums up the 95& "I don't care"
Most don't care because they find sound/music is not that important to care. Others are negatively biased so that they do not care to be open about what they hear. And finally, there may be some who really do not register better sound.

fMRi may well sort out those groups?

5%’er and proud of it!

 

[mountainman bob]

It doesn't seem to be important so I give it a rest.

Emotional response to music definately has something to do with how it’s played back (not just the music itself) because I’ve made changes over the years that has made it go away......once it’s there you definately know when it’s gone and getting it back is a long arduous task of fiddling and tuning of things that aren’t supposed to matter. I keep coming back to phase as the explanation....I’m not sure if it’s even correct phase that gives me what I’m after as it’s all done by ear.

 

[scottjoplin]

It doesn't seem to be important so I give it a rest.

No matter, it's about definitions, I thought that was clear. I've been looking at actual research into "emoacoustics"

 

[mmerrill99]

It doesn't seem to be important so I give it a rest.

Emotional response to music definately has something to do with how it’s played back (not just the music itself) because I’ve made changes over the years that has made it go away......once it’s there you definately know when it’s gone and getting it back is a long arduous task of fiddling and tuning of things that aren’t supposed to matter. I keep coming back to phase as the explanation....I’m not sure if it’s even correct phase that gives me what I’m after as it’s all done by ear.

I'm not sure what ScottJ is asking but I agree with MB - our interest in & response to music playback can be diminished by the playback system & corollary of this is that some playback systems enhance this insight, interest, response to the music. There are many guesses as to what's in the playback waveform that is causing these changes but measuring the waveform factors that cause this has proved to be elusive & hence the call for other approaches to measurement.

Apart from using test signals which are not a good analog of the dynamics of a music signal, I feel another part of the measurement problem is that we are using measurements which typically ignore the workings of auditory perception. Yes, there is a basic understanding of thresholds of hearing & anything not falling into this very basic range is considered inaudible. sing thresholds which have been established by testing with tone signals in mono is again not representative of the binaural experience of listening to everyday sound or indeed our playback systems. This factor has been recognised in perceptual testing also - the use of more complex test signals.

After all, our auditory perception is analyzing & categorizing a stream of individual signals so what comes before & after each moment in the signal, affects our perception. So how different parts of the signal at different times in the stream relate to each other defines how we perceive the various sound objects in the sound stream. If we were to use this perspective, it may change the approach to measurements?

 

[Max Headroom]

In stock implementations it to my ears lacks dynamics, particularly in the bass. Higher frequencies seem to me to be less than pristine clean. Could be expectation bias though as I know the OPS is fed from a charge pump which won't exactly have low impedance. What tweaks have you implemented?

I bought one of these CM6631A PRO boards without the case - CM6631/ES9023 USB DAC AUD$49.99





Dan.

 

[hhoyt]

Emotional response to music definately has something to do with how it’s played back (not just the music itself) because I’ve made changes over the years that has made it go away......once it’s there you definately know when it’s gone and getting it back is a long arduous task of fiddling and tuning of things that aren’t supposed to matter. I keep coming back to phase as the explanation....I’m not sure if it’s even correct phase that gives me what I’m after as it’s all done by ear.

I hear what you are saying, and indeed it is difficult to separate the fun and joy of reproduction (ahem) from the emotional content in the music, and we may be merely mis-communicating or have a semantic difference. However you just said it comes and goes with the same piece of music heard on different systems. This says to me by simple subtraction of variables it is at least in part your joy of the act of listening coupled with the piece of music itself. I think these are two separate things.

As an example (and I hope I don't insult anyone's musical taste here) for years when demoing systems at AES shows we used Sheffield tracks from the James Newton Howard disc. They are superbly recorded and really highlight the dynamics of a system. However, for me most of the tracks are musical pablum. Superbly recorded pablum, but... SO here's my point: when setting up these LEDE systems, we had to do room treatments, speaker alignments, etc. When everything fell into place, I often got chills and the hair stood up on my arms because the sound was coherent, dynamic and present.

My bodily response was not to the music because #1, I disliked it, #2, I had heard it so many times bile rose in my throat when it started up. I was responding to how (relatively) real the system sounded, which had nothing to do with the music particularly other than it's fidelity attributes. Furthermore, if it was played at a low level I experienced none of the response. I conclude, in this case at least, our bodies can respond to the perceived near presence of a sound, or music, which does not have a direct relationship to the piece being played. It is an autonomous nervous response to a strong sensory stimulus. And as you state, the more convincing the illusion, the more our subconscious is fooled into thinking the stimulus is a real thing to be paid attention to.

If this is what you mean by an emotional response, we are in complete agreement! I think this may be the main difference between an audio enthusiast and a normal person (emphasis on normal). We respond more intensely to the degree of correctness in the illusion than say, your kids or the guy in the cubical next to you at work.

Interesting subject!
Howie

 

[mountainman bob]

I hear what you are saying, and indeed it is difficult to separate the fun and joy of reproduction (ahem) from the emotional content in the music, and we may be merely mis-communicating or have a semantic difference. However you just said it comes and goes with the same piece of music heard on different systems. This says to me by simple subtraction of variables it is at least in part your joy of the act of listening coupled with the piece of music itself. I think these are two separate things.

As an example (and I hope I don't insult anyone's musical taste here) for years when demoing systems at AES shows we used Sheffield tracks from the James Newton Howard disc. They are superbly recorded and really highlight the dynamics of a system. However, for me most of the tracks are musical pablum. Superbly recorded pablum, but... SO here's my point: when setting up these LEDE systems, we had to do room treatments, speaker alignments, etc. When everything fell into place, I often got chills and the hair stood up on my arms because the sound was coherent, dynamic and present.

My bodily response was not to the music because #1, I disliked it, #2, I had heard it so many times bile rose in my throat when it started up. I was responding to how (relatively) real the system sounded, which had nothing to do with the music particularly other than it's fidelity attributes. Furthermore, if it was played at a low level I experienced none of the response. I conclude, in this case at least, our bodies can respond to the perceived near presence of a sound, or music, which does not have a direct relationship to the piece being played. It is an autonomous nervous response to a strong sensory stimulus. And as you state, the more convincing the illusion, the more our subconscious is fooled into thinking the stimulus is a real thing to be paid attention to.

If this is what you mean by an emotional response, we are in complete agreement! I think this may be the main difference between an audio enthusiast and a normal person (emphasis on normal). We respond more intensely to the degree of correctness in the illusion than say, your kids or the guy in the cubical next to you at work.

Interesting subject!
Howie

Yes.....100%.....Yes,

Thank you for wording it a bit more intelligently

 

[mountainman bob]

Apart from using test signals which are not a good analog of the dynamics of a music signal, I feel another part of the measurement problem is that we are using measurements which typically ignore the workings of auditory perception. Yes, there is a basic understanding of thresholds of hearing & anything not falling into this very basic range is considered inaudible. sing thresholds which have been established by testing with tone signals in mono is again not representative of the binaural experience of listening to everyday sound or indeed our playback systems. This factor has been recognised in perceptual testing also - the use of more complex test signals.

After all, our auditory perception is analyzing & categorizing a stream of individual signals so what comes before & after each moment in the signal, affects our perception. So how different parts of the signal at different times in the stream relate to each other defines how we perceive the various sound objects in the sound stream. If we were to use this perspective, it may change the approach to measurements?

I’d say studying the test subjects in their natural habitats (their own listening room) with their own gear set up for ‘preference’ instead of the ‘lab’ would probably yield better results in this case?

 

[Tournesol]

I also have a 9023 DAC Actually does not sound bad. I think it was originally targeted at the mobile market.

Could-you confirm or infirm that your differents DACs sound different to your ears ?

 

[scottjoplin]

Apart from using test signals which are not a good analog of the dynamics of a music signal, I feel another part of the measurement problem is that we are using measurements which typically ignore the workings of auditory perception.

Déjà vu? What you said earlier about comparing the signal that hits our ears with the signal from the source is what's necessary makes sense to me because it means we can pretty much forget about psychoacoustics because it would be the nearest we can get to the original event. So that, to my mind, is the real challenge.

 

[Max Headroom]

Folks do like to use multitone testing and then look between the test signal at the change in noise floor. As it is low frequencies that tend to mask higher frequencies a slightly different look may be of interest to you.

Try a 190 hertz four or more pole (or synthesized equivalent) pink noise source very slowly swept n level as the test signal. Then look below 10 hertz for what appears as the change in 1/f noise. I think that may show you interesting results.

I used to have a nice test file for the source but am pretty sure I lost it in a crash. I suspect many of the folks here can quickly produce a test file.

Hi Ed, if you could find that file that would be great.....I am not certain of what you mean in your description.
What did you find ?.


Dan.

 

[mmerrill99]

@howie - yes, agree that's what I was trying to say too & MB also. It's some factors in the waveform that gives rise to this.

Déjà vu? What you said earlier about comparing the signal that hits our ears with the signal from the source is what's necessary makes sense to me because it means we can pretty much forget about psychoacoustics because it would be the nearest we can get to the original event. So that, to my mind, is the real challenge.

Yes, but a understanding of what auditory perception considers are the important factors in this signal stream & design/analyze measurements accordingly.

Still a long way to go to achieve this

 

[johnego]

My bodily response was not to the music because #1, I disliked it, #2, I had heard it so many times bile rose in my throat when it started up. I was responding to how (relatively) real the system sounded, which had nothing to do with the music particularly other than it's fidelity attributes. Furthermore, if it was played at a low level I experienced none of the response.

It doesn't make sense. Unless you did enjoy the music, or you're not in the 5% club

Being wowed by sound system that produce 'real' sound is not equal to enjoying music. It is equal to being amazed to anything. Equals to an audiophile who plays a recording of an helicopter with an exciter. "Wow! Hear that sound!"

Singers are trained to create musical sound through voice, melody and emotion. Musical instruments are designed so that they can produce musical sound. Musicians are trained so that they can produce musical sound using the instruments. A simple guitar strum does not sound 'the same' with oscilloscope falling down from the table.

Furthermore, if it was played at a low level I experienced none of the response.

May be the music was 'broken' by that. Some music requires the existence of (phase accurate) low frequency sounds to be musical. Some music like Beethoven's Fur Elise will not sound gorgeous with small speakers. And our ears have unique non linearity with sound level (The Fletcher-Munson curve changes with sound level). At low volume level, our ears perceived the bass as attenuated.

 

[Max Headroom]

I’m sure it does sound good. Nothing wrong with the CM6631A or the ES9023. The more integrated parts like the 9023 are probably harder to mess up.

Yeah, this design looks to be perfect copy of datasheet schematic, pretty hard to screw up such a minimalist design.

To those around here who believe there is some sort of consensus on sound quality across devices or topologies - please take note that Max very much likes what some around here have scoffed at and would consider a mid-fi or worse converter chip - sigma delta voltage out, low power, built in ASRC, short filters, integrated charge pump. Might even have some 8-legs in the box. How could that be? I thought digital, negative feedback, and switching power supplies are the devil according to some prominent posters on this thread?

Yes, this board does have devils like charge pump negative supply, but it does have decent passives and DC coupled output.
As delivered the sound has always been 'pretty good' by standard subjective measures but not really engaging or moreable.
This is all different now and the result as I have it now is the best sound I have had so far in my career in audio.

 

[Evenharmonics]

Not every post is an objection to anyone's claim/post, but I have heard people claimed that all (well measured) amps sound the same. If so, it means my statement (one amp can be best at several aspects of quality but not all) was wrong.

I have heard all kinds of things including a claim that you are in audio business but in disguise on internet forums. But then it's just a hearsay so I won't believe it fully.

 

[Evenharmonics]

Understood. They are listenable for casual listening purposes, but don't stand up to closer scrutiny from my listening perspective. Most people probably wouldn't notice or care, IME.

What is your listening perspective?

Unfortunately, most of the people here wanting better sound quality don't understand enough about electronics to know how to figure out what is actually causing their small-ish but audible (to some) SQ problems.

Most people here? When and where did you take a survey to conclude that?

There are a few real engineers around here willing to help constructively, but not enough, and most seem to have the good sense to avoid Blowtorch. I should probably try harder to ignore the bait myself, but the intolerance for perceptive listeners can be hard to let stand.

Asking technical questions on listening method is considered the bait?

I would say they are carefully designed to meet a low price point, and to look good with pictures and claims that can help persuade buyers who can't compare by listening first.

Most of the Chinese ES9038Q2M boards use a voltage mode output stage design that they all copy. It only takes one dual opamp instead of usual three. Those that use three opamps usually do something else bad, like implement a poorly filtered SMPS that produces ugly audible artifacts. They all use cheap very piezoelectric bypass caps, cheap everything. But, they use a good quality dac chip!

There is another, better class of Chinese dac boards besides the ones I linked to. They are also carefully designed, but to a higher price point, maybe a $150 or a little less. It is common for people around diyaudio to buy one and fix it up to sound better with some better parts, put it in a case, and sell it close to home in Eastern Europe where people don't have better options they can afford. Some of the people doing that are actually pretty knowledgeable, they aren't just stupid like some here seem to assume.

Have you listened to cheap built-in DACs of mainstream brands like Philips blu-ray player or Yamaha receiver?

 

[scottjoplin]

Yes, but a understanding of what auditory perception considers are the important factors in this signal stream & design/analyze measurements accordingly.
Still a long way to go to achieve this

Why not presume it's all equally important, isn't that the simpler more logical thing to do?