| pooge |
| quote: | Originally posted by Peter Daniel
I'm using TO-220 aluminum oxide pads under LM1875. It works fine and sounds better than silpads (less damping, I guess, results in more airy sound) |
I don't understand your rational here. I can't understand why you think less damping is undesirable. I can only think that the "less air" description is more accurate and neutral reproduction, and your "more air" is actually artifacts due to mechanical vibration in the chip, i.e., a euphonic coloration. I don't understand why you choose to spend so much effort balancing so many euphonic colorations. Then, when you change something, you have to go back and start all over again. Why not neutralize the colorations, so you have less variables. I know you think that everything colorizes, but why knowlingly add them? |
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| millwood |
| Quite frankly I don't understand why different pads should sound different. If the amp is that sensitive to minor changes in the environment, how usable is it? |
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| Peter Daniel |
| quote: | Originally posted by pooge
"I'm using TO-220 aluminum oxide pads under LM1875. It works fine and sounds better than silpads (less damping, I guess, results in more airy sound)." Peter Daniel
I don't understand your rational here. I can't understand why you think less damping is undesirable. I can only think that the "less air" description is more accurate and neutral reproduction, and your "more air" is actually artifacts due to mechanical vibration in the chip, i.e., a euphonic coloration. I don't understand why you choose to spend so much effort balancing so many euphonic colorations. Then, when you change something, you have to go back and start all over again. Why not neutralize the colorations, so you have less variables. I know you think that everything colorizes, but why knowlingly add them? |
I actually think, that less damping is desirable. And how you know what a neutral reproduction really is? Maybe that's what you get with less damping or more damping, depending on the rest of a setup. There is no simple answer for that. Ever listened to unechoic orchestral rechording? It doesn't have any colorations, but doesn't sound like music either. |
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| pooge |
"I actually think, that less damping is desirable. And how you know what a neutral reproduction really is? Maybe that's what you get with less damping or more damping, depending on the rest of a setup. There is no simple answer for that. Ever listened to unechoic orchestral rechording? It doesn't have any colorations, but doesn't sound like music either."
I think it is simple. By keeping the chip from vibrating, you are causing less generation of noise, or other spurious signals or delayed resonances, from the likes of piezo type generations, etc. This, BY DEFINITION, is more neutral than allowing the chip to vibrate and create spurious colorations, euphonic or otherwize. If you like them, fine. But I don't think you can call these vibrations more accurate or neutral just because you like them better. You are advocating using parts as a tone control. If you don't like the sound with damped components that don't generate spurious euphonics, then maybe should look elsewhere to "fix" things to your liking, and leaving the noise/resonances out of the equation.
I don't think your analogy to unechoic orchestrat recordings apply here. Your are trying to accurately amplify an existing recording. If you add colorations, you are not doing this. If you don't like the result of damped components, maybe it's the recording you should blame (or other weak link). However, if you add resonances by not damping, it seems obvious that finding and fixing other problems will be much more elusive and difficult, and make your amp inherently sensitive to mating with other components. |
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| Peter Daniel |
I am not that crazy about adding vibrations, but rather controling and redistributing (because you can't get rid of them completely). Talking specifically here, about insulating pads, none of this pads prevents the chip from vibration. It just happens, that I prefer the sound of a chip with aluminum oxide pad and not silpad. But silpad doesn't eliminate the vibrations from a chip, it just makes it for a different kind.
I sugggest you make some experiments of your own, instead of jumping to the conclusion that damping is a cure for everything. It is simply not. I think it is simple;)
I never mentioned that I want to create an amp that would be a tool for analyzing recordings. Since most of them don't sound that well, there is no reason to do that. I prefer the equipment that makes music. If this is not neutral to you, I don't mind if you don't agree with me.
It is relatively simple to create a neutral sounding amp and there are many of them around. But if you read carefully some better reviews, you will notice that they usually don't try to describe how the amp reproduces the recording, but how well it reproduces the musical notes, little details, acoustic space and soundstage. There are not that many amps that make it really well.
| quote: | Originally posted by pooge
You are advocating using parts as a tone control. If you don't like the sound with damped components that don't generate spurious euphonics, then maybe should look elsewhere to "fix" things to your liking, and leaving the noise/resonances out of the equation.
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How do you damp the componenets and make sure that they don't vibrate? And what can you do to leave the resonances out of equasion? |
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| pooge |
I don't recall ever saying that damping is the cure for everything.
You stated damping was the reason for the difference in sound you say you heard. However, as true damping is resistive conversion (i.e. energy removal) rather than energy spreading, I do see a fundamental advantage in that.
Basically, my argument is that you concluded the reason for your preference of one sound over the other is attributed to damping, when the difference you say you heard may not even have anything to do with damping (leaving your followers to believe that neither silpads nor damping is a good thing). Did you do any "experiments" to confirm that this variable alone is the reason for those "differences" you say you heard to make such a conclusion? Why are you trying to throw this burden on me? And please do not hold up your preference as a valid experiment for me to prove wrong.
"I never mentioned that I want to create an amp that would be a tool for analyzing recordings. Since most of them don't sound that well, there is no reason to do that."
True. You never said you were trying to create an accurate amp, just what sounds good to you; and I do not argue this is illegal, immoral, or reprihensible. However, I (and I'm sure many others) do see a reason to do just "that". (BTW, I lean more to the side that defines an accurate amp as one that creates an identical replica of the input, and has the ablity to sink back EMF from a speaker, rather than one that simply tickles my rectum.)
Have fun in your quest for the holy bandaids. (OK, I admit that was a low shot. If you prefer an amp euphonically tuned to you liking, go for it.) |
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| Peter Daniel |
| quote: | Originally posted by pooge
You stated damping was the reason for the difference in sound you say you heard. However, as true damping is resistive conversion (i.e. energy removal) rather than energy spreading, I do see a fundamental advantage in that.
Basically, my argument is that you concluded the reason for your preference of one sound over the other is attributed to damping, when the difference you say you heard may not even have anything to do with damping (leaving your followers to believe that neither silpads nor damping is a good thing). Did you do any "experiments" to confirm that this variable alone is the reason for those "differences" you say you heard to make such a conclusion? Why are you trying to throw this burden on me? And please do not hold up your preference as a valid experiment for me to prove wrong.
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If you refrained from low shots and read more carefully, you would noticed that it was my guess not a statement. I didn't do extensive experiments in that area, just one try, but my previous findings may actually confirm that it is damping related.
| quote: | Originally posted by Peter Daniel
I'm using TO-220 aluminum oxide pads under LM1875. It works fine and sounds better than silpads (less damping, I guess, results in more airy sound). |
It seems like I might learn something from you here. So what exactly you do differently from me, so that your amp can sound more "neutral" and "accurate"?
| quote: | Originally posted by pooge
True. You never said you were trying to create an accurate amp, just what sounds good to you; and I do not argue this is illegal, immoral, or reprihensible. However, I (and I'm sure many others) do see a reason to do just "that". (BTW, I lean more to the side that defines an accurate amp as one that creates an identical replica of the input, and has the ablity to sink back EMF from a speaker, rather than one that simply tickles my rectum.)
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| Peter Daniel |
| quote: | Originally posted by pooge
I don't recall ever saying that damping is the cure for everything.
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Of course you didn't. But from your reasoning it seems like less "euphonically tuned" component would create more neutral sound. Wouldn't than, maximum damping of any audio component be recommended? |
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| pooge |
I can think of absolutely no plausible reason why allowing a component to vibrate to the point that sound is altered (other than a mike or speaker) could possibly make it more accurate or neutral, by definition. I simply cannot believe that keeping a component from vibrating, if it is not a transducer, can have any possible detriment to accuracy. Increases in airyness due to removal of damping strongly implies added or delayed resonances to me; much like that attributed to phono reproduction. That is, of course, if damping is the reason for the change. It might sound more lively, but how can it possibly be more accurate.
As to what I do different: I try to put at least some trust in fundamentals rather than trust my hearing 100%. In other words, if it makes absolutely no sense that allowing a component to vibrate could possibly make it more accurate, I have to presume that the increased airiness I hear should not be there. I don't really care to get into an objectivist vs. subjectivist debate, because I don't like any extreme positions like that.
I just have a different philosophy. Instead of trying to offset one problem by adding a component with an opposite problem, I'd much prefer to neutralize the initial problem in the first place. I desire an accurate system that has a chance to reproduce exactly was was recorded. True, a lot of recordings really suck, and the better the resolution of the system, the more this is true. But recording can get better. Modern CDs can be outstanding.
How many times have you heard what you thought was an improvement because it was more "exciting" or "lively", only to tire of it after extended listening, choosing to go back to the more "boring" or neutral sound? Ears are fickle. |
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| Peter Daniel |
I think we have a misunderstanding here. It started from my post, about using one or the other insulating pad under the chip.
Now, this chip is mounted on 3/4" thick 2" x 8" aluminum bar. I stated that I prefer the sound of aluminum oxide pad over the silpad. I cannnot imagine that using aluminum oxide pad is creating more vibration in a chip than using silpads. I can only imagine that the resonant frequency might be altered by one or the other type of pads, but never eliminated completely.
According to what you try to suggest, I purposly mount the components so they can vibrate to create so called "euphonic" sound. This is nonsense.
I simply noticed, that no matter how well the components are mounted, or how well the chassis is built, it will still show complex vibrational modes, which can be altered in one way or another.
You can take your most heavily built Krell amp (or whatever else you prefer to choose) and still alter its sound by means of different supporting platform or material under the feet. There is no way you can avoided that. Now, by proper tuning and allowing one or the other type of resonances, you can change the sound of that unit. It is still accurate and neutral (because its made by Krell;)), yet the sound can be altered more or less to your prefference.
Was this unit designed to be "euphonicaly" colored? I guess not, but in certain setups it may seem to be like that and in other setups, it can be sounding overdamped and "neutral". Please note that I'm still talking about the same amp, just that the sound can be changed in one way or another.
I would never allow myself to deliberatly design a piece of equipment to have some parts loose or vibrating purposely. I just noticed that whatever you do, you still have to deal with the issues of resonances. Now, it is your preference and personal taste, how you to go about them;)
I particularly like this statement, taken from 47Labs site:
Another radical approach we took, which is often neglected or paid least attention to, is the control of mechanical resonance. We do not automatically consider vibrations as negative. After all, vibrations and electrical current come from the same energy. Instead of damping and trying to kill the vibrations, which instantly causes delays and modulations in the flow of current, we release them smoothly and quickly by the design of a compact and rigid chassis construction and control the resonance with the choice of materials. So, there is no damping materials or suspensions in our products at all. |
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| Peter Daniel |
| quote: | Originally posted by pooge
How many times have you heard what you thought was an improvement because it was more "exciting" or "lively", only to tire of it after extended listening, choosing to go back to the more "boring" or neutral sound? Ears are fickle. |
Quite a few, and indeed my temptation was to go back to more boring and neutral sound, but I never did it. I always managed to find a better alternative. This is also a never ending search and a constant quest for that ultimate "holy bandaids".;) |
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| chris ma |
Hi,
I hope this question I am asking is not too off topic of the thread.
What is the best way to isolate the mounting screws from the transistors or TO-220 diodes and heatsink. For example the way Peter Daniel's discrete rectifier uses one screw to mount two TO-220 diodes sandwiches or sharing a heatsink. Plastic screws?
Any tips?
Regards,
Chris |
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| Peter Daniel |
| Plastc screw is OK when not much pressure is required (diodes), but on ICs and transistors, I'm using metal screw (non magnetic) and a plastic washer (I buy from Supremetronic). |
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| pooge |
| quote: | | After all, vibrations and electrical current come from the same energy. Instead of damping and trying to kill the vibrations, which instantly causes delays and modulations in the flow of current, we release them smoothly and quickly by the design of a compact and rigid chassis construction and control the resonance with the choice of materials. So, there is no damping materials or suspensions in our products at all. |
This makes absolutely no sense. Vibrations and current do not come from the same energy. How in the hell does killing vibrations cause delays and modulations in the flow of current? The opposite would be more likely. Where are the vibrations "released" to? How are the resonances "controlled"? Sounds like new age marketing **** to me. |
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| Peter Daniel |
| quote: | Originally posted by pooge
This makes absolutely no sense. Vibrations and current do not come from the same energy. How in the hell does killing vibrations cause delays and modulations in the flow of current? The opposite would be more likely. Where are the vibrations "released" to? How are the resonances "controlled"? Sounds like new age marketing **** to me. |
That's not my statement, but I just happen to like it.
Whould you like to comment, what kind of different energies they do come from (vibrations and current)? |
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| millwood |
| quote: | Originally posted by Peter Daniel
That's not my statement, but I just happen to like it.
Whould you like to comment, what kind of different energies they do come from (vibrations and current)? |
but you did say that less damping results in airy sound. Maybe you would like to comment on exactly how that is done? |
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| Peter Daniel |
| quote: | Originally posted by millwood
but you did say that less damping results in airy sound. Maybe you would like to comment on exactly how that is done? |
It is still a guess, but this is what I think.
Aluminum oxide pad is made of ceramic like material, which is very hard and brittle. Silpad is more soft in comparison.
When insulating pad is used, any vibrations that occur in aluminum chassis are transfered through the pad to the chip. Since both pads have different physical properties, they also change the amount and type of resonances passing to the chip. I would imagine that hard and brittle material can introduce more airy sound, while something that is softer, more laid back and toned down character. What do you think? |
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| jh6you |
| quote: | Originally posted by Peter Daniel
I would imagine... What do you think?
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I think that the mechanical vibration energy is too weak to change the position of electrons and protons at rest (or moving at certain speed) inside a conductor (and semi-conductor). This means that only the electrical energy could be believed as the inertia force for the electrons and protons.
JH |
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| millwood |
| quote: | Originally posted by Peter Daniel
Since both pads have different physical properties, they also change the amount and type of resonances passing to the chip.
[QUOTE]Originally posted by Peter Daniel
[B]I would imagine that hard and brittle material can introduce more airy sound, while something that is softer, more laid back and toned down character. What do you think? |
I am not sure. Foundamentally, that's the question that pooge asked and I have no answer for it. I have not personally read any impact that mechanical vibrations may have on electric characteristics of a semiconductor device. I do know that stress can generate noise but that is too low to be noticed here. Plus, the whole die is mounted on the base plate so even if there is vibration of the whole plate, there is be limited stress on the die itself. |
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| millwood |
Peter, I respect you as much as anybody else on this forum. and I think it is an understatement to say that I have learnt a lot from you all. and I am sure that will remain ture for the rest of my life.
But that doesn't mean that I wouldn't ask tough questions, and that doesn't mean that I can be pushed aside, qualification or otherewise.
We are here because we love DIY audio, and we are eager to pick up new things from each other. If there is a qualification, that's it. Not your background in electronics (or not), or my background in banking, whatever. |
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| Peter Daniel |
It is our choice to accept or refuse anything we read. The reason I edited and re-edited the post multiple times, was because I wanted to use minimum words for maximum content. Did I succeed?;)
The vibrational influence may be even harder to accept than the difference in resistors sound, but when you once realize its existance, your approach to audio design changes. |
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| millwood |
| quote: | Originally posted by Peter Daniel
The vibrational influence may be even harder to accept than the difference in resistors sound, but when you once realize its existance, your approach to audio design changes. |
if you haven't demonstrated its existence, how can we possibly accept it?
If you could show, convincingly may I add, that damping of electronic devices using aluminum oxide and sil pads has audioable impact of their electronic properties / performance, you would have made a HUGE (no, GIGANTIC) contribution to human being's understanding of electronics.
The fact that we haven't heard of anything remotely close to what you are proclaiming should dampen your enthusiasim a little bit, :)
But that's not to say that billions of people and millions of scientists couldn't be wrong and you couldn't be right. But the odds aren't exactly in your favor, if you ask me. |
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| Peter Daniel |
| quote: | Originally posted by millwood
if you haven't demonstrated its existence, how can we possibly accept it?
If you could show, convincingly may I add, that damping of electronic devices using aluminum oxide and sil pads has audioable impact of their electronic properties / performance, you would have made a HUGE (no, GIGANTIC) contribution to human being's understanding of electronics.
The fact that we haven't heard of anything remotely close to what you are proclaiming should dampen your enthusiasim a little bit, :)
But that's not to say that billions of people and millions of scientists couldn't be wrong and you couldn't be right. But the odds aren't exactly in your favor, if you ask me. |
I should ask you again, to speak for yourself only.
How possibly on this forum can I demonstrate its existence? I can only suggest its existance and its absolutely up to you to check it out. I assume you didn't do anything in that area yet. If you didn't, you cannot also demonstrate lack of its existance.
It's very easy to critisize and joke about someone elses efforts, like starting a silly thread and quoting others. With that you didn't do any contribution at all, but created conflict. What were the odds for that? |
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| jh6you |
| quote: | Originally posted by Peter Daniel
The vibrational influence...
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Once I put my power amp on one crappy speaker and turned up the volume. You know what happened in the sound? Nothing because I was using Silpad below the chips. Very romantic... :)
JH |
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| Peter Daniel |
I guess you didn't see that thread:
http://www.diyaudio.com/forums/show...&threadid=17641
I don't care were did you put your amp, as long as you have fun doing that. I also don't understand what issues you have with my comments regarding vibrations. If you don't believe or observe its influence, why are you concerned that I do? I also believe there are other forum members who will make an efort to investigate it further, instead of only joking about it. |
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| ronc |
During a long stint at boeing aerospace we had to test electronic assys. using vibration on what we called "the shaker".It was a skid that was designed to move the test subjects at frequencies from 1 cps(hertz) to greater than 30K hertz.The circuit was active and monitored while testing.Yes vibrations do cause changes in the response , but these were lets say greater amplitude vibrations, probably much greater than a sound wave (in a normal listening room enviorment) would produce.The greatest effect was on caps, and it was found out that the peaks and dips of the response werent really constant between like circuits.BTW this is a MIL spec requirement that all circuit be burned in for a 24 hr. period then given the shake test.We did find out that a softer potting material gave much better responses but never completly eliminated the out of base line curve response.
ron |
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| rikkitikkitavi |
Peter, I think that Al2O3 insulators are more
vibration transparent than silpads.
The silpad is a composite of a polymer binder with SiO2 or some other solid material with high heat transfer capacity. Composites usually dampens vibrations quite good, expecially the polymeric part of it.
/rickard |
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| Peter Daniel |
| quote: | Originally posted by rikkitikkitavi
Peter, I think that Al2O3 insulators are more
vibration transparent than silpads.
The silpad is a composite of a polymer binder with SiO2 or some other solid material with high heat transfer capacity. Composites usually dampens vibrations quite good, expecially the polymeric part of it.
/rickard |
That's exactly my point. They more more vibration transparent and it can be heard. |
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| Fred Dieckmann |
"They more more vibration transparent"
What in the heck does that mean? Ummm.... there are screws holding the device to the chassis as well, aren't there. There might be a couple of other considerations as well, but I don't want to bias or taint Peter's independent R and D, since all his design decisions are independent of information from forum discussions. |
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| pooge |
| quote: | | That's exactly my point. They more more vibration transparent and it can be heard. |
So what is the origin of these vibrations, and why do you want to hear them??
Peter, your hearing borders on superhuman ability. I am not in any position to state that what you hear does not exist, so I am not going to criticize you about it. However, you claim to hear things that I've never heard anyone else say they can hear. Also, since I haven't read all of your 5000+ posts, I don't know how you conduct your listening tests. However, if you, for example, change the feedback resistors, and thereby the gain, and don't volume match two side-by-side amps that are different only in the feedback resistor (i.e. their volume), and listen to them virtually at the same sitting, then your conclusions don't hold any validity to a lot of us, especially when some of the changes you hear don't sound like something that could be audible to mortals.
I realize that you are doing all this for yourself, and aren't concerned about proving anything to us (i.e., if you hear it, that's all that matters), but please don't expect a lot of us to accept these things you hear if you listen to a component, break it down, change something, go back and listen to it later, and suggest there's a change. It just doesn't work like that. Hell, my system changes daily depending on my mental/emotional state before I press "play" (and other unknown reasons), and that's without making ANY changes to the hardware. |
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| Peter Daniel |
| quote: | Originally posted by Fred Dieckmann
"They more more vibration transparent"
...but I don't want to bias or taint Peter's independent R and D, since all his design decisions are independent of information from forum discussions. |
And as you've probably noticed, they are clearly against most popular POV.;) Glad you can appreciate that. |
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| Peter Daniel |
| quote: | Originally posted by pooge
So what is the origin of these vibrations, and why do you want to hear them??
Peter, your hearing borders on superhuman ability. I am not in any position to state that what you hear does not exist, so I am not going to criticize you about it. However, you claim to hear things that I've never heard anyone else say they can hear. Also, since I haven't read all of your 5000+ posts, I don't know how you conduct your listening tests. However, if you, for example, change the feedback resistors, and thereby the gain, and don't volume match two side-by-side amps that are different only in the feedback resistor (i.e. their volume), and listen to them virtually at the same sitting, then your conclusions don't hold any validity to a lot of us, especially when some of the changes you hear don't sound like something that could be audible to mortals. |
I don't care what's the origin of those vibration. As long as they are present, I have to deal with them. Because I can't eliminate them completely, I prefer to tune them and actually get advantage of them. I don't have suprhuman hearing abilities, but your acceptance threshold is probably at very low level.
You can't say that anyone else didn't hear what I'm talking about, because I saw many posts concerning similar issues. I never do any critical comparisons myself alone, but usually with some other people and we share our experiences. And volume levels are usually taken care of with test signals and meters, if you were not sure.
| quote: | Originally posted by pooge
I realize that you are doing all this for yourself, and aren't concerned about proving anything to us (i.e., if you hear it, that's all that matters), but please don't expect a lot of us to accept these things you hear if you listen to a component, break it down, change something, go back and listen to it later, and suggest there's a change. It just doesn't work like that. Hell, my system changes daily depending on my mental/emotional state before I press "play" (and other unknown reasons), and that's without making ANY changes to the hardware. |
How the heck did you get the idea that I expect the whole lot of you to accept those things. You must be kidding here. I only share my observation and it's up to you how you use it. But only because you don't accept it, you want me to stop posting or share my findings? You must be kidding again.;) |
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| jh6you |
| quote: | Originally posted by Peter Daniel
If you don't believe or observe its influence, why are you concerned that I do?
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Because, in my opinion, now you are the more than a diyer and I hope there will be a cautious comment about the fact not publically acceptable yet.
JH |
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| Peter Daniel |
| I guess I have to keep low profile now, that's what you trying to say? |
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| millwood |
| quote: | Originally posted by Peter Daniel
How possibly on this forum can I demonstrate its existence? |
for example, you can tell a few reviewers of that and see if they hear; you can also go back to your college electronics books and see if there are some theories / emperical studies on that; etc.
| quote: | Originally posted by ron clarke
Yes vibrations do cause changes in the response , but these were lets say greater amplitude vibrations, probably much greater than a sound wave (in a normal listening room enviorment) would produce. |
Ron: you hit it right on. We are not here to debate if the impact exists or not (it does for sure). We are debate if it is significant enough for others to hear it. |
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| Peter Daniel |
| quote: | Originally posted by jh6you
Because, in my opinion, now you are the more than a diyer |
I somehow noticed that too. Fred's attitude towards me, changed sort of;) |
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| millwood |
| quote: | Originally posted by Peter Daniel
As long as they are present, I have to deal with them. |
you don't. For example, you don't need to be concerned about the impact that blackhole in Zeta galaxy may have on your amp; or how different your amp would sound if a dog in Argintina starts to bark at 2am vs. 9pm, to list just a few.
Why? Common sense dictates that they don't raise to the level of any significance.
| quote: | Originally posted by Peter Daniel
But only because you don't accept it, you want me to stop posting or share my findings? You must be kidding again.;) |
No. Just the opposite. You have been one of the largest contributors of this forum and we love to hear from you what you are experimenting. It is just that as part of us accepting your R&D, we want to think it a little bit to make sure that it makes sense.
| quote: | Originally posted by Peter Daniel
I guess I have to keep low profile now, that's what you trying to say? |
See my note above. It would have been a tragedy if you did tat. |
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| Peter Daniel |
| quote: | Originally posted by millwood
I hope that you were not referring to the now-deleted thread where Rod Elliot talked about his impression of gainclone.
That is his point of view, Peter. As you had asked us to let you freely express yourself, Rod should also have the right to free expression and shouldn't be afraid of called "silly". To me, the resistor sound and vibration-caused-airy-sound are by far sillier but that's just me.
Let's focus on the sound and science of the devices, not the person. |
This thread is not deleted, but only closed and you can still see the irony of it. I'm trying to focus on sound, but it seems that you prefer to focus on science.
Your claiming that talking about sound of resistors is silly only confirms your ignorance in that matter. Even Fred would agree on that. |
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| jh6you |
| May I propose coffee break for two hours? |
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| millwood |
I didn't find anything explicit on insulatin pads. but did find the mentioning of an experiment that author did with transformers.
when he moved the transformer from rubber pads to bare metal (less damping), the sound improved;
he then moved the transformer to a sand bag (more damping), the sound improved;
he further moved the transformer to inner tubing (more or less damping?), the sound improved further.
In another experiement, he moved the PCB frmo nylon standoffs to brass standoffs (less damping), the sound improved.
so was he trying to prove that more or less damping gives better sound? |
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| Peter Daniel |
| quote: | Originally posted by millwood
I didn't find anything explicit on insulatin pads. but did find the mentioning of an experiment that author did with transformers.
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Insulating pads are mentioned here: http://www.soundstage.com/maxdb/maxdb101998.htm |
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| millwood |
| quote: | Originally posted by jh6you
May I propose coffee break for two hours? |
I am tired too.
btw, are you in Shanghai, China? I was there last November. Beautiful and vibrant city. |
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| Peter Daniel |
The thread is located here: http://www.diyaudio.com/forums/show...6052#post206052
Because it is OffTopic section, the listing is not shown as other regular threads.
9mm is the length of feedback loop (basically resistors length). I still didn't figure out how the 47Labs calculate signal path length, as looking at the arangement inside thei amp it has to be longer than 39mm. I'm claiming in my amp 120mm, which includes RCA jacks and binding posts. |
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| jh6you |
| quote: | Originally posted by millwood
btw, are you in Shanghai, China?
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I am in Pusan this month and flying back to Shanghai on the beginning of the next month. Yes, Shanghai attracts me, too, and it's the city quite different form the time 15 years ago. If you have another chance to visit to Shanghai, I would invite you to a bar I usually go.
JH |
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| millwood |
| quote: | Originally posted by jh6you
and it's the city quite different form the time 15 years ago. |
I went to Shanghai multiple times. The first was in 1991 (I think I landed the day of the coup in Russia that got Gobuchev house-arrested). after that a few business trips. Would love to work there for a couple of years. |
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| pooge |
| quote: | | I don't have suprhuman hearing abilities, but your acceptance threshold is probably at very low level. |
Man, you sure got that right.
1) You haven't shown that "vibrations" from, whereever, have anything to do with what you hear.
2) You haven't shown that silpads damp any more than the insulators you use. For all I know, you can be damping more with the ones you use by a tighter coupling to the greater mass of the heat sink, and getting more resolution by virtue of less smear from vibrations.
3) You haven't ruled out other possible effects such as dielectric, thermal properties, etc.
4) You quote some goobledygook from some company as support, and then accuse me of having a low threshold of acceptance. You haven't come close to reaching any threshold of making an acceptable conclusion.
Come on Peter, don't **** on my foot and tell me it's raining. This isn't a personal attack. It's not like I'm the only one questioning you here. Some of the things you are chasing, like an x mm path length vs. an x+1 mm pathlength, etc., appear to more of a reaction to cloning a company's product that got a good review, and then espoused some mysticism for it, rather than . I applaud your effort to search and try and listen. But unless you show reasonably controlled experiments, maybe you ought to ease off on the explaining, and not insist that we prove you correct. |
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| SY |
Peter: As per usual, I'll be happy to help you design an experiment to confirm whether or not changing insulator pads changes the actual sound. That way, you can confirm (or not) that you actually hear a difference, and if so, give the rest of us a motivation to determine the mechanism.
I still want to do the fancy versus cheap cap/resistor test and I still have the necessary super-high-quality switch. My concept could easily be adapted to testing two or four gain channels with different insulators, if you can help out with the mechanics- I'm pretty good at experimental design, but will never be your equal at machining and mechanical design. |
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| Peter Daniel |
| quote: | Originally posted by pooge
But unless you show reasonably controlled experiments, maybe you ought to ease off on the explaining, and not insist that we prove you correct. |
I won't show you any contolled experiments, because I don't need to prove anything and I don't see a convenient way to carry it out. Would you like to come to Toronto?
Did you try to compare both pads yourself and came to a conclusion? If not, you are wasting the bandwith with your pointless argument.
As far as I'm concerned, I also didn't explain anything and didn't present any conclusion. I'm not qualified for that enough. I just posted my guesses and some of my findings. It's your business what you do about it.
I'm not chasing the shortest signal path. It just happens that this is a convenient way to put things together. If I quoted anybody, it was mostly for entertainment purposes.
As much as you want me to prove my claims, I can ask you to prove yours. I don't see a difference here. We went through cables make no difference threads and everybody knows what kind of people are most active in those.
I'm in exactly same position to say to you:
>>Come on man, don't **** on my foot and tell me it's raining.<<
Am I? |
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| Peter Daniel |
| quote: | Originally posted by pooge
2) You haven't shown that silpads damp any more than the insulators you use. For all I know, you can be damping more with the ones you use by a tighter coupling to the greater mass of the heat sink, and getting more resolution by virtue of less smear from vibrations.
3) You haven't ruled out other possible effects such as dielectric, thermal properties, etc.
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You missing my point again. I didn't want to show or prove that AO pads are better than silpads. I just mentioned that in my application, in my specific example, I had preference of one over the other. Do you get it? In that example, the heatsink mass was the same and pressure of the screw was the same. My guess was , that if I hear a difference, it may be because of different damping created by different pads.
It might be the exact opposite, in a different application and setup.
So tell me, what exactly are you after? Are you just angry that I hear more than you? If that's so, you are funny man, pooge. |
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| Peter Daniel |
| quote: | Originally posted by SY
Peter: As per usual, I'll be happy to help you design an experiment to confirm whether or not changing insulator pads changes the actual sound. That way, you can confirm (or not) that you actually hear a difference, and if so, give the rest of us a motivation to determine the mechanism.
I still want to do the fancy versus cheap cap/resistor test and I still have the necessary super-high-quality switch. My concept could easily be adapted to testing two or four gain channels with different insulators, if you can help out with the mechanics- I'm pretty good at experimental design, but will never be your equal at machining and mechanical design. |
I'm fed up with the constant **** about "parts don't make difference". I don't care much for insulators as those are the only type I wan't to use, but if you have an idea for 4 resistors switching box, with different values, feel free to contact me or start a new thread. I'll make that device and we can circulate it on the forum.
This time's for real;) |
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| millwood |
| quote: | Originally posted by Peter Daniel
I'll make that device and we can circulate it on the forum.
This time's for real;) |
good, finally we can prove or disprove the myth of that ellusive "resistor sound", :) |
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| Peter Daniel |
| quote: | Originally posted by millwood
good, finally we can prove or disprove the myth of that ellusive "resistor sound", :) |
Did it occur to you that by using word "myth" you already "disprove" the resistors sound. |
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| millwood |
| quote: | Originally posted by Peter Daniel
Did it occur to you that by using word "myth" you already "disprove" the resistors sound. |
I am not aware of it. | quote: | Originally posted by Peter Daniel
Were did you get this idea from? Present me with a reasonable way to prove it and I'll do my best to comply. |
I thought SY had presented one set-up. and i am sure if you put your efforts to it, you will come up with many ways to show it. |
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| SY |
| Peter: Well, let's start easy with Rs and Cs, and if you're encouraged by how that works out, we can discuss other variables- like insulators. |
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| millwood |
| quote: | Originally posted by Peter Daniel
That's the biggest BS I've heard today. |
no need to insult others even if you cannot answer their questions, Peter. you know better than that, right?
| quote: | Originally posted by Peter Daniel
SY and me, will work on resistors setup. I thought you were mostly interested in pads today. Can you suggest a clever way to a setup that can prove a difference (if you need a prove of course). |
Peter, this is what SY offered:| quote: | Peter: As per usual, I'll be happy to help you design an experiment to confirm whether or not changing insulator pads changes the actual sound. That way, you can confirm (or not) that you actually hear a difference, and if so, give the rest of us a motivation to determine the mechanism.
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Please let me know if that is not sufficient and why so we can address your needs promptly.
| quote: | Originally posted by Peter Daniel
If I believe or not has nothing to do with having a will and desire to prove it. So what is it telling? |
not sure if I understand your point. Would you mind clarifying it a little?
| quote: | Originally posted by Peter Daniel
Man, you are wasting everybody's time again. I've seen people like you on this forum before. They come, make some noise about issues they have no clue about and then disappear. Our conversation is over. |
I can assure you, Peter, that I am here to stay, much to your delight I am sure, :). |
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| millwood |
| quote: | Originally posted by SY
Peter: Well, let's start easy with Rs and Cs, and if you're encouraged by how that works out, we can discuss other variables- like insulators. |
Thanks, SY, for your help. We look forward to update from you and Peter as it progresses.
Good night to all. |
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| Peter Daniel |
| quote: | Originally posted by millwood
no need to insult others even if you cannot answer their questions, Peter. you know better than that, right?
Peter, this is what SY offered:
Please let me know if that is not sufficient and why so we can address your needs promptly.
not sure if I understand your point. Would you mind clarifying it a little?
I can assure you, Peter, that I am here to stay, much to your delight I am sure, :). |
Actually I feel insulted by your ignorance and pointless persistance. Pointless, because I will not build a setup for pads testing. Will you build it? If nobody's going to do that, how can you test the pads? You can tease me with addressing my needs promptly, but the most work would have to be done by me. Only to prove to you my point? Don't you think it's ridiculous? |
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| Mad_K |
| quote: | Originally posted by Peter Daniel
It might be the exact opposite, in a different application and setup.
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Yupp! I also tried both AO and std silicon rubber insulators in my GC, and I found that I liked the silicon rubber best. I didn't think that hard about it, I just preferred the sound that way. (My chassis is vibrating a bit.) I also preferred std rubber feet vs Pulsar Points and the like. Sounds more natural/musical to me;) |
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| janneman |
| quote: | Originally posted by Peter Daniel
It is still a guess, but this is what I think.
Aluminum oxide pad is made of ceramic like material, which is very hard and brittle. Silpad is more soft in comparison.
When insulating pad is used, any vibrations that occur in aluminum chassis are transfered through the pad to the chip. Since both pads have different physical properties, they also change the amount and type of resonances passing to the chip. I would imagine that hard and brittle material can introduce more airy sound, while something that is softer, more laid back and toned down character. What do you think? |
Peter, I have a lot of respect for your work, but this is quite un-scientific. I can follow that depending on the type of isolation pad, there will be a difference in the transmission of vibrations to the transistor. But it is too much to jump from that to "airy" or dull sound. For starters, you have to prove that this transmission to the transistor does change the sound coming out of the speaker.
You fall in the same trap as those people buying those car starter cables to connect to your neighbours car when yours got a flat battery. They invariably have a tiny copper cable with enormous isolation around it. They look like garden hose, and the uninitiated will think, wow, look at those massive cables! I'm sure my car will HAVE to start with that!
Jan Didden
/Science = the belief in the ignorance of the experts (Richard Feynman, The pleasure of finding things out). |
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| jh6you |
Hi Jan Didden
Idling car engine...?
Have you ever been onboard VLCC (Very Large Crude Oil Carrier), which has a big engine of about 30,000BHP? Sometimes, such a ship is poorly designed and resulted in terrible vibration on the bridge, where important electrical navigation equipment like radar, radio, sonar and many more are located. Even after a repairing, the vibration problem still remains to certain degrees.
For this reason and in case, we should require by rules that all navigation equipments are to be certified after having environment tests for the regulated vibrations (and temperature, humidity) before being installed onboard. Yes, the vibration tests with respect to the given criterion of frequency-range, displacement and acceleration amplitudes. Very essential!
By the way, all these test requirements are put on considering potential failures of mechanism of the equipment, not considering potential interruption of traffic of the current flow inside conductors (semiconductors). All my colleges, Scandinavian electrician, in our office look at me, huh?, whenever I ask them about the relation of the machanical vibration and the current flow interruption”¦
Just a chap based on my profession, as you talked about the idling car... and as this thread moved to here, Everything Else...
JH
PS, I also respect Peter Daniel's works and I hope he will cool down a little bit on his good humor... |
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| analog_sa |
| quote: | | but this is quite un-scientific |
But of course it is. Has anyone ever heard a 'scientifically' designed amp which sounds not merely acceptable, but brilliant? The current 'science' guidelines produce pretty mundane sound and anything which sounds better is based on empirical principles rather than orthodox science. Examples in the world of amps are numerous. As audio fanatics, we have only one sensible guideline: to get closer to what our ears say is right. A bit of engineering know-how is absolutely essential to get a project to a working point, bit above that point lies a void of unexplored and unexplained in the textbooks, where only experience, far fetched theories and a good ear will help.
Of course, at this stage, the ones who can hear will never be able to reconcile their differences with the ones who can't. If i have to be honest, if i was half deaf, i'd be a bigger sceptic than... better not to mention names :) The sceptic's position is so much easier after all. And so much more sensible. Plus a ton of 'evidence' to support it. However, i somehow don't feel jealous.
peter |
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| AudioFreak |
| Has anyone discussed the differences in parasitics introduced by the various insulator pads? I would think that this has the potential to alter sonics slightly. |
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| ALW |
How about all of you sceptical types trying the following experiment.
1. Take one of your analogue components (say a line stage or power amp) and stick a cushion under it.
2. Listen for 2 - 3 days to a range of music.
3. Remove cushion
4. Repeat (2).
5. Tell us if you hear a difference, if you do, try and measure it.
6. Report back
I get really fed up with these discussions, they never go anywhere and the resolving capability of most DIY'ers test gear is insufficient to resolve effects I know are there. If you can't hear it, don't worry, if you can, just deal with it (which is where the engineering comes in).
Minds and ears work best when open, but I will add that as an aerospace engineer the sensitivity of electronics to relatively small amounts of vibration is something that I've had to deal with regularly - RF PLL's are one of the worst in this regard, often being acutely sensitive to low levels of vibration, in a very obvious and measurable way.
Andy. |
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| janneman |
| quote: | Originally posted by analog_sa
But of course it is. Has anyone ever heard a 'scientifically' designed amp which sounds not merely acceptable, but brilliant? The current 'science' guidelines produce pretty mundane sound and anything which sounds better is based on empirical principles rather than orthodox science. Examples in the world of amps are numerous. As audio fanatics, we have only one sensible guideline: to get closer to what our ears say is right. A bit of engineering know-how is absolutely essential to get a project to a working point, bit above that point lies a void of unexplored and unexplained in the textbooks, where only experience, far fetched theories and a good ear will help.
Of course, at this stage, the ones who can hear will never be able to reconcile their differences with the ones who can't. If i have to be honest, if i was half deaf, i'd be a bigger sceptic than... better not to mention names :) The sceptic's position is so much easier after all. And so much more sensible. Plus a ton of 'evidence' to support it. However, i somehow don't feel jealous.
peter |
Analog,
I was very unclear, I apologize. What I meant to say that the METHOD to get an answer is un-scientifically. I strongly believe that the ONLY way to make meaningfull progress about anything is the scientific method, ie to methodologically analyse the situation, try to find out what the problem is and solve it. In this case (and I by no means want to single out Peter) the step from realising that different pads transmit mechanical vibrations differently, to the conclusion that that gives either airy or dull sound is totally unscientific. First, prove that the vibrations DO change the sound, which I am not sure off. THEN see if you can find out HOW it changes the sound (more harmonics? only change in freq response?). And your examples are very interesting, and surely we don't want the ship's arials to fall off because of vibration, but I don't think it is relevant to the problem at hand.
Jan Didden |
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| ALW |
| quote: | | First, prove that the vibrations DO change the sound, which I am not sure off. THEN see if you can find out HOW it changes the sound (more harmonics? only change in freq response?) |
Whilst I agree partly with the above, it comes first from the assumption that the proof comes from measurement.
Does the fact that one can hear it not count?
Surely that HAS to be a starting point, the analysis / engineering follows from that. The problem is what happens if you cannot resolve the measurement, with the apparatus at hand?
This is a DIY Audio forum and not everyone is blessed with owning an AP, or a sufficiently good FFT spectrum analyser. What are these people to do, ignore the evidence of their ears, convince themselves that what they hear is an illusion, or make their music less enjoyable simply because they can't prove to others what they hear?
If I find something sounds better, I'm hardly going to ignore that evidence when designing something new, simply because I cannot prove the existence of an effect.
None of the above BTW is an attempt to argue AGAINST measurement, but simply that in my experience the ability to resolve the effects is a huge challenge to a DIY'er and that if we take this view we will drive away a healthy active community with vested interests.
We should rememeber that the goal is the enjoyment of music, not measurement; how it sounds is ALL that ultimately matters.
For those that like to prove / understand things better let them, but do not put down the views of others because they do not, or cannot provide 'proof'.
There is plenty of evidence in the real world of manufacturers going to great lengths to deal with vibration in audio electronics, and I doubt they do this just for the fun of it.
Andy. |
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| janneman |
| quote: | Originally posted by ALW
Whilst I agree partly with the above, it comes first from the assumption that the proof comes from measurement.
Does the fact that one can hear it not count?
Surely that HAS to be a starting point, the analysis / engineering follows from that. The problem is what happens if you cannot resolve the measurement, with the apparatus at hand?
This is a DIY Audio forum and not everyone is blessed with owning an AP, or a sufficiently good FFT spectrum analyser. What are these people to do, ignore the evidence of their ears, convince themselves that what they hear is an illusion, or make their music less enjoyable simply because they can't prove to others what they hear?
If I find something sounds better, I'm hardly going to ignore that evidence when designing something new, simply because I cannot prove the existence of an effect.
None of the above BTW is an attempt to argue AGAINST measurement, but simply that in my experience the ability to resolve the effects is a huge challenge to a DIY'er and that if we take this view we will drive away a healthy active community with vested interests.
We should rememeber that the goal is the enjoyment of music, not measurement; how it sounds is ALL that ultimately matters.
For those that like to prove / understand things better let them, but do not put down the views of others because they do not, or cannot provide 'proof'.
There is plenty of evidence in the real world of manufacturers going to great lengths to deal with vibration in audio electronics, and I doubt they do this just for the fun of it.
Andy. |
OK Andy, I fully understand your point. But what is the alternative? Everybody rushes out to replace the silicone pads under their TO220's because that gets rid of the dull sound? I don't expect everybody to start frantically measuring this. But I would hope that we use more the intellectual capabilities we have been given freely. Or maybe I should take the stand, hey, they're just having fun, what the heck? Maybe that's my problem, I'm treating this all too serious.
Jan Didden |
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| ALW |
| quote: | | But what is the alternative? Everybody rushes out to replace the silicone pads under their TO220's because that gets rid of the dull sound? |
It think that others should try them and report back, those of us with the right kit, may even like to take some measurements.
The bit I do have a problem with is the pseudo-science that Peter offers as explanation, he should simply state that he preferred the sound of the pads in his amp, and tell us what he heard.
FWIW, there's vibration and of course simple electrical issues like capacitance to factor in - these pads are much thicker than standard mica or SIL-pads, if I'm not mistaken - this is just as likely to affect the sound and be measurable.
The thermal performance will be different too, with different mechanical characteristics at different temps, vis-a-vis SIL-pads.
Andy. |
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| jcarr |
Andy:
>there's vibration and simple electrical issues like capacitance - these pads are much thicker than standard mica or SIL-pads - this is just as likely to affect the sound and be measurable.<
That was my reaction, too. I would immediately suspect varying degrees of capacitive coupling to ground (or whatever voltage potential the chassis is at), and whatever effect that coupling may have on the stability and high-frequency behaviour of the circuit in question.
Incidentally, the initial production versions of the GainCard had a rather longer signal path that what it is now. One day, Kimura and Teramura mentioned that they had shortened the physical length of the feedback loop (I believe that they soldered the feedback resistor directly to the IC legs, as close up to the IC body as possible). They reported significantly better sound as a result. Now a physically short feedback loop is something that we (Petr Mares and myself) had already been doing for years, and drawing on my own experience, I asked Kimura if the IC's operating temperature decreased when the feedback loop was shortened. He replied in the affirmative.
My conclusion was and is that the original version of the Gaincard circuit had been suffering from low-level oscillation at high frequencies. Physically shortening the feedback loop and reducing the associated parasitics stabilized the amplifier, and the sound improved as a result.
hth, jonathan carr
PS. Andy, did you receive my reply with the additional distortion data? |
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| analog_sa |
Jan
| quote: | | THEN see if you can find out HOW it changes the sound (more harmonics? only change in freq response?). |
All the years i've spent messing with audio i've heard little evidence that my ears are very sensitive to either frequency response anomalies or excessive thd. Yes, some people obsess about riaa accuracy, but i am more likely to hear a different type of cap in riaa than a db or two out of perfect. Same with thd; in many respects SET amps are far from perfect sonically, but perceived distortion is not one of their problems. Measurements may be invaluable in designing better PS regulators and you may even see some correlation between perceived and measured performance, but to expect that vibration control of a semiconductor device would result any measurable difference in thd and freq linearity is very naive. Surely all these effects are way below the threshold of what is commonly measurable, as to why we hear them, i am as stumped as everyone else, but we do.
In my mind, the highly non-linear way we hear and the very sophisticated (and mysterious) signal processing which follows the ears are responsible for a perceived sound very different from what one's common sense leads to expect. To my ears, the effects which cannot commonly be measured, such as these caused by wire, mechanical construction, dielectrics, vibration control, power supply etc have more influence on the final perception of musicality and naturalness than any combination of 'objective' parameters. Or in short: circuit topology may be responsible for 35-40% of the final sound, the rest is the result of empirical observations and of course science, but applied in a very unscientific way.
peter |
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| ALW |
| quote: | | We just need to prove that the sound difference exists |
That is though the basic premise that I have a problem with.
1. That we NEED to prove it
2. That you CAN prove it.
As I've said many times before, it's not possible to conduct a listening test (no matter how scientific one tries to be) that can PROVE anything - proof requires hard factual results, determined by measurable objective criteria.
Listening though is a subjective assessment with no known measurable correlation and can therefore never provide proof. Since the basic premise being discussed stems from subjective assessment, we have a problem.
One can find correlation between sound and measurement, but you can never absolutely determine the one from the other.
Peter has dug himself a hole, but is wise not to engage in a proof, simply because it cannot be done.
No-one has ever written down a scientific procedure that can provide such proof, despite my asking several forum contributors on many occasions. I'm happy for someone to do so, if they think proof, as opposed to evidence, can be the result.
Andy |
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| fdegrove |
Hi,
From my POV, in this case it should be possible to measure the difference given the right equipment.
The reason is that not only the mechanical damping is altered but also the amount of stray capacitance and quite likely the operating temperature of the chip(s).
Maybe a null test can bring it up also...assuming one accepts that as sufficient proof...for it seems that those wanting proof always find themselves ways to disprove.:devily:
Cheers,;) |
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| millwood |
| quote: | Originally posted by ALW
That is though the basic premise that I have a problem with.
1. That we NEED to prove it
2. That you CAN prove it.
As I've said many times before, it's not possible to conduct a listening test (no matter how scientific one tries to be) that can PROVE anything - proof requires hard factual results, determined by measurable objective criteria.
Listening though is a subjective assessment with no known measurable correlation and can therefore never provide proof. Since the basic premise being discussed stems from subjective assessment, we have a problem.
One can find correlation between sound and measurement, but you can never absolutely determine the one from the other.
Peter has dug himself a hole, but is wise not to engage in a proof, simply because it cannot be done.
No-one has ever written down a scientific procedure that can provide such proof, despite my asking several forum contributors on many occasions. I'm happy for someone to do so, if they think proof, as opposed to evidence, can be the result.
Andy |
Let's me dress your first assertion first since your reply is for the most part focusing on the 2nd half.
We are here for the pursuit of better sound (Peter's venture not withstanding). And if "better sound" doesn't need proving, how confusing do you think it is?
One could come here and assert all sorts of crazy things and what would a newbie like myself who has no qualification in audio / electric engineering and who doesn't understand squat about electric engineering, as some of the forum members had asserted before do?
What would be there to prevent or at least keep in check people from making questionable / false claims for purposes other than DIY audio (Peter, in case you jump on this, I am not implying that you are one of them)?
As to the science to prove it. I am not sure 1) any proof is absolute. and 2) you need objective measurements to prove it.
In this world, no thing is absolute (other than the statement itself, :)). what we believe to be true is likely to turn out to be false in the future. and there are enough examples of that so let's move onto the 2nd point.
I don't think our understanding of human hearing and present state of engineering will allow us to measure everything there is in human hearing. and I am not sure if we will ever get there.
so it is paramount that one accepts the limitation of our measurement systems and prepares oneself for the ultimate measurement system: our ears.
The use of humans as measurement itself introduces another set of challenges. The least of which is our subjectivity. Through careful design and experiment, however, one can hope, but not be guarantteed, to arrive at an objective (in the sense of it coming from a large sample and reflecting the view of the population it represents) view on a rather subjective matter.
One such test is the Tube vs. Transistor test article published or linked at Dr. Leach's site.
and it is my view that doing a similar test (maybe not to that kind of extent) will be extremely helpful to solidify Peter's claims on a series of matters and restore his credibility in the community.
But I personally find puzzling the inconsistency or sharp contrast between Peter's insistence on the pad-sound and his going to length trying to avoid a test, between his elaborate and creative experiments on various components in his gainclone amp and his seemingly challenged state of affairs on methdologies one may employ to affirm the pad-sound.
But, what does a fool like me know about the mystic land called high-end audio? :) |
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| millwood |
| quote: | Originally posted by ALW
No-one has ever written down a scientific procedure that can provide such proof, despite my asking several forum contributors on many occasions.
Andy |
Andy, I am happy to provide one, if you are OK with it. I am not sure how scientific it is, tho.
How about getting a few test subjects. Divide them into three groups. Those who believe in pad sound, whose who don't, and those who don't know about it.
Provide two identical gaincard amps, one with a silpad (amp S) and one with an AO pad (amp AO). do the usually trick of volume adjusting them, etc.
Conduct a series of double blind A vs. B listening tests, and ask the subjects two questions:
1) if A is different from B;
2) if A is preferred over B.
A / B can be either amp S, amp AO, or both. So the possible combinations are
amp S, amp S
amp S, amp AO
amp AO, amp S
amp AO, amp AO.
at alpha of 95%, run a hypothesise that amp S sounds the same as amp AO. (t-test I believe).
at the same confidence level, run another hypothesis that amp S is preferred over amp AO.
it would be interesting to know how well doug blackburn will do in such a test, :) |
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| ALW |
What time interval do you propose for your tests and evaluations?
The ear can only detect certain fundamantal changes during a relatively short assessment time (read: minutes, hours).
During this time one can make simple assesments related to amplitude and frequency balance. This is the problem with DBT - short time spans, matched amplitudes etc. reduce the ability to determine any difference at all. It's a null result, not a proof.
The assessment of the underlying improvement in the music (totally unrelated to both the above criteria) often only comes after several days listening, or at least a good few hours. This is a critical point - frequency response errors, changes in amplitude have NO EFFECT whatsoever on the fundamentals of the music, providing the devices are operating within their envelopes, and the changes are not so extreme as to cause other ill-effects.
This is what makes many people think that speakers are the worst part in the chain, as they have the grossest reponse / amplitude errors. They are most important to the sound least important to the music.
Quick A/B's do not work, they fail to take into account the way we hear, the processing of which occurs in the brain.
I think Jonathan Carr's method, proposed previously, of making externally identical amplifiers labelled A / B or C, with the salient details identified internally is a better method.
One has to ensure that the insides cannot be seen / viewed without obvious evidence you then simply pass these amps onto a number of individuals who report their experience / preference over a long time period. The data / listening notes are then analysed subsequently.
How many times have you changed something with the immediate result that you think it's better, only to find, several days later that it isn't? This is a common theme amongst those of us actually doing this stuff.
I've done a lot of design work with remote partners, where improvements have been made and both of us have reported identical results, sonically, and this has often been with people I would view as having daimetrically opposed views to my own, with different systems, musical tastes etc.
I strongly believe that better is better for most people and this has been a most surprising finding for me, the difference in opinions solely comes down to the actual location you are along the audio path to nirvana - I may not like your system, you may hate mine, but an improvement to a common area is likely to be the same to both of us.
Andy. |
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| SY |
| quote: | | Whilst I agree partly with the above, it comes first from the assumption that the proof comes from measurement. |
Quite the opposite. Peter is claiming to have possibly found an interesting phenomenon. Putting aside the notions of analogy, there's not much in the way of a clear mechanism in the electronics to explain this- unless Audio Freak's hypothesis is correct. Either way, there's potentially something important here, and those of us who would love to see the state of the art advanced, rather than just speculated about, are trying to figure out a way to pin this down.
Now, measurement is a fine thing IF you know what you're looking for. And IF you know you're not chasing a chimera. So the first thing that has to be done is to take the instrument that is giving the "funny" result (in this case, Peter's perceptual system) and run the experiment. It's possible that there's a real phenomenon here. It's also possible that Peter is falling into the normal human trap of bias and expectation. It's improper to assume one or the other in the absence of evidence. So the way to cut this problem in half is by LISTENING, not measuring.
And fortunately, through more than a century of sensory research, the methods exist to use the human faculty of listening to determine what's going on. Since Peter, like most of us, doesn't have much experience with sensory testing, my suggestion has mutated to something about which he (and apparently others) feel just as confident, but less emotional.
So, let's give the rhetoric a rest and start with some baby steps. |
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| ALW |
| quote: | | And fortunately, through more than a century of sensory research, the methods exist to use the human faculty of listening to determine what's going on |
Sy,
I have no problem with much of what you say and believe that Peters analysis of the cause / effect may be wrong, in this case. Not that there isn't a difference, but simply that his theory may not be the reason for it.
The above though, I do have a problem with, for the reasons stated above, most A/B or DBT's are fundamentally flawed, but I've not personally seen any evidence that these issues have been dealt with.
I'm happy to be shown evidence to the contrary though.
The tests proposed thus far are flawed, can you point me towards yours?
Andy.
Edit: just found relevant thread - will read first! |
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| Peter Daniel |
| quote: | Originally posted by janneman
But what is the alternative? Everybody rushes out to replace the silicone pads under their TO220's because that gets rid of the dull sound? |
This shouldn't be the case, as one other member mentioned that he preffered the sound of silicone pads and not AO.
| quote: | Originally posted by ALW
The bit I do have a problem with is the pseudo-science that Peter offers as explanation, he should simply state that he preferred the sound of the pads in his amp, and tell us what he heard.
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I never stated that one is better than the other, or tried to seriously explain the process behind it. Whatever I did was only my guess, I stressed it few times and I always claimed that this is only my prefference in a given setup. Check the posts. |
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| Peter Daniel |
| quote: | Originally posted by millwood
you first complained about no one offering you a chance to test it. SY volunteered. Now, you are telling us flat out that you will not do it.
Hm, interesting.
Peter, I am here to learn from everyone (you included). And if you think for a split second that I wouldn't persistently ask questions (to either you or somebody else) about claims made to this forum, you are out of your mind. So prepare yourself for some persistence from this ignorant banker, :)
What are we serious about,Peter?
Andy, SY had offered that to Peter after Peter complained about not one supporting such an experiment. Looks now that Peter doesn't want to do it somehow.
Do you know why?
It does. We just need to prove that the sound difference exists. At this point, its biggest proponent, Peter, is adamant about NOT doing such a test. Maybe we can persuade his otherwise?
Somehow, I don't think so. |
Millwood,
You don't give up, do you? If you built the test circuit for the pads, I will gladly perform tests. I can also provide any assistance you might need. I'm sure SY will too. I believe it was you complaining about nobody's testing it, so don't blame it on me. So this is my position on that and stop your constant rant about me not being eager to do it. I simply have other priorities and not enough time.
Now tell me something, why do you need that proof? Will it improve your hearing? |
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| SY |
| quote: | | Now tell me something, why do you need that proof? Will it improve your hearing? |
A superb philosophical question. It won't improve anyone's hearing, but it lets the engineering-minded among us know what's worth chasing. |
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| janneman |
Wow, what a slew of posts!
A couple of comments from my POV | | | |
