Well you know what my advice is... if at all possible start doing blind testing or at least null testing and go from there.Peter Daniel said:
As for comparing notes with someone else and coming up with similar descriptions for a given tweak, there are many possible explanations for that. Sometimes they heard or read about it (or something like it) elsewhere so they were biased in the same direction as you.
Sometimes one friend tips the other off with a "leading" conversation (i.e. "didn't it make the sound warmer in your system?" is an obvious one). These tips can be subtle but are often there in one form or another (i.e. in previous conversations, etc.). Often one person forgets or doesn't realize they lead the other person's conclusions in some way.
Sometimes people hear what they expect to hear based on just intuition from other common factors--in this case the aluminum oxide was hard so you both perhaps expected it to sound hard or harsh compared to a soft insulator (granted this may not be the best example, but this sort of thing comes up all the time in the audiophile world). The mind works in funny ways.
Finally, it's not that hard for pure random luck to cause many comments to align in the audiophile world. You don't have to put very many people in the same room for two of them to often have the same birthday. The often used "audiophile adjectives" (in any given year) number much less than less than 365 (the number of possible birthdays). So, it's more likely than you might think for people discussing the same piece of equipment or tweak to use some of the same descriptions to describe it--even if they're all random.
Of course, there's also the possibility you both heard the same thing because it really IS audible and repeatable. In that case, it should show up in a blind test!
Peter Daniel said:
That's really interesting Peter. Have you tried swapping the insulating pads between two identical amps to see if the effects follow (to avoid any other change)?
Pure speculation now, but reading this also brought other possible mechanisms for what you heard to mind. Is there a significant difference in the thermal conductivity between the Kapton and the aluminum oxide pads? I have heard the effects of power compression in a speaker (heating of the voice coil increases impedance which causes the power delivered to the speaker to drop) . Perhaps something similar is happening to the dynamic response of the amp? These chip amps have some interesting thermal protective circuitry inside them. Perhaps thermal spikes are causing the chip protection to engage for an instant?
Phil
Those amps when not pushed to the limits are running rather cold and my findings were observed in first half hour of operation so the chip was not even warm. So the thermal issues shouldn't be really influential here.
I noticed that the amp is very sensitive to the way it is placed on a shelf (shelf or platform material and the feet beeing used) Depending on a setup it was better with the spikes, but sometimes only one spike in front and two acrylic feet at the back was preffered. The chassiss is very compact and the chip is mounted directly to the rear panel. If the chassiss pics up any vibration , the chip as well, the only thing separating them is thermal pad. The screw shouldn't be much issue, because of plastic washer under. And my sonic impressions were in line with a properties of material constituting a pad. With double coated kapton the sound was kind of mellow and flat, with aluminum oxide washer it got more vibrancy and life. Also at the time I was experiencing it, I wasn't even considering a pad as something contributing to the sound. I came to it later.
I noticed that the amp is very sensitive to the way it is placed on a shelf (shelf or platform material and the feet beeing used) Depending on a setup it was better with the spikes, but sometimes only one spike in front and two acrylic feet at the back was preffered. The chassiss is very compact and the chip is mounted directly to the rear panel. If the chassiss pics up any vibration , the chip as well, the only thing separating them is thermal pad. The screw shouldn't be much issue, because of plastic washer under. And my sonic impressions were in line with a properties of material constituting a pad. With double coated kapton the sound was kind of mellow and flat, with aluminum oxide washer it got more vibrancy and life. Also at the time I was experiencing it, I wasn't even considering a pad as something contributing to the sound. I came to it later.
Re: Re: Topological acuity....
Sorry, I missed this one originally.
Yes, "static" was a poor choice of words on my part. Steady state would have been more appropriate.
Yeah?
Tell me, how would you evaluate an amplifier's impulse response with a single steady state sinusoid?
Also, why do you say "cosinusoidal"? When you're talking about a single steady state sinusoid, the difference between a sine and cosine is irrelevant.
se
Sorry, I missed this one originally.
mikek said:
Yes, "static" was a poor choice of words on my part. Steady state would have been more appropriate.
Yeah?
Tell me, how would you evaluate an amplifier's impulse response with a single steady state sinusoid?
Also, why do you say "cosinusoidal"? When you're talking about a single steady state sinusoid, the difference between a sine and cosine is irrelevant.
se
Steve is right, IMO
It's sort of funny that people are happy to apply logic to digital circuits but logic sometimes goes out the window when it comes to analogue circuits.
Test:
Earlier someone said that a real music signal can be represented as an infinite collection of sinewaves (hence Fourrier transforms). Then they reasoned that if music is a collection of sinewaves a single sinewave is an adequate representation of music for the purposes of analysing distortion in an amplifier. What is wrong with this reasoning?
It's sort of funny that people are happy to apply logic to digital circuits but logic sometimes goes out the window when it comes to analogue circuits.
Test:
Earlier someone said that a real music signal can be represented as an infinite collection of sinewaves (hence Fourrier transforms). Then they reasoned that if music is a collection of sinewaves a single sinewave is an adequate representation of music for the purposes of analysing distortion in an amplifier. What is wrong with this reasoning?
nail clippings
I think you'll find it's "experience" that is the desirable attribute.
You are compelling me to take sides with Fred because he talks about results and you talk about publicists and then insult Fred. I know you are a confident, budding designer who is getting air-time in an electronics publication and so you are naturally inclined to have the greatest respect for other publicists who preceeded you.
But before you drop names everywhere to back your arguments and plagiarize those who've published tombs, remember that a designer is only as good as his last design, regardless of how you quantify experience. Consider the best sounding amps in the world, who designed them? Are any of them on your list?
I think you'll find it's "experience" that is the desirable attribute.
You are compelling me to take sides with Fred because he talks about results and you talk about publicists and then insult Fred. I know you are a confident, budding designer who is getting air-time in an electronics publication and so you are naturally inclined to have the greatest respect for other publicists who preceeded you.
But before you drop names everywhere to back your arguments and plagiarize those who've published tombs, remember that a designer is only as good as his last design, regardless of how you quantify experience. Consider the best sounding amps in the world, who designed them? Are any of them on your list?
Re: Steve is right, IMO
Simply that music is not a steady state signal like a sinewave, imagine for instance a snare hit. this contains a huge number of frequencies, all with a particular attack/decay, and for any test to be viable it has to cope with this transient change in amplitude, as well as correctly reproducing the individual frquencies of the sound.
BTW the development of this discussion virtually parrallels that of discussions on testing such phenomena as ESP and dowsing
, and in cases such as those that seem to have a particular ability in these subjects, no matter how highly their scoring starts, it always tends to average out over time...
traderbam said:
Simply that music is not a steady state signal like a sinewave, imagine for instance a snare hit. this contains a huge number of frequencies, all with a particular attack/decay, and for any test to be viable it has to cope with this transient change in amplitude, as well as correctly reproducing the individual frquencies of the sound.
BTW the development of this discussion virtually parrallels that of discussions on testing such phenomena as ESP and dowsing
, and in cases such as those that seem to have a particular ability in these subjects, no matter how highly their scoring starts, it always tends to average out over time...cosinusoids...
In analogue signal processing, it is more usefull to consider such excitations as a complex voltage, Ve^(jwt)=(Vcoswt+jVsinwt). This aids the determination of steady state response of a network to a sinusoid, because the complex exponential time waveform, e^(jwt) remains in the same form after differentiation or integration. This vastly simplfies analysis...as the real part of the applied voltage, which is cosinusoidal, (Vcoswt), is then used to solve of other quantities such as phase, fourier components, currents, etc..without the inelegant tedium of resorting to trignometric identities...
....you just try to solve for the curent in a simple L-R series circuit resulting from applied excitation Vcos(wt)....(assuming zero initial conditions for simplicity), using trig. identities....tedious...tedious.....
Steve Eddy said:
In analogue signal processing, it is more usefull to consider such excitations as a complex voltage, Ve^(jwt)=(Vcoswt+jVsinwt). This aids the determination of steady state response of a network to a sinusoid, because the complex exponential time waveform, e^(jwt) remains in the same form after differentiation or integration. This vastly simplfies analysis...as the real part of the applied voltage, which is cosinusoidal, (Vcoswt), is then used to solve of other quantities such as phase, fourier components, currents, etc..without the inelegant tedium of resorting to trignometric identities...
....you just try to solve for the curent in a simple L-R series circuit resulting from applied excitation Vcos(wt)....(assuming zero initial conditions for simplicity), using trig. identities....tedious...tedious.....
Re: nail clippings
Hi traderbam...
No...i did not insult Fred......with respect, i suggest the bulk of cutting edge audio today is designed by AES members...eg Robert stuart of Boothroyd- stuart Meridian, who uguably design and manufacture the best all-round, and technically advanced HI-Fi in the world here in the UK.....
However i confess, i do find your accusation of 'plagarism' insulting...indeed defamatory....you of course are incapable of adducing any evidence to back up such an unprovoked piece of scurilous nonsense?
...and as for
'I know you are a confident, budding designer who is getting air-time in an electronics publication and so you are naturally inclined to have the greatest respect for other publicists who preceeded you.
.......please desist from patronising me, as you do not know me at all.....and me you for that matter...
cheers.
traderbam said:
I think you'll find it's "experience" that is the desirable attribute.
You are compelling me to take sides with Fred because he talks about results and you talk about publicists and then insult Fred. I know you are a confident, budding designer who is getting air-time in an electronics publication and so you are naturally inclined to have the greatest respect for other publicists who preceeded you.
But before you drop names everywhere to back your arguments and plagiarize those who've published tombs, remember that a designer is only as good as his last design, regardless of how you quantify experience. Consider the best sounding amps in the world, who designed them? Are any of them on your list?
Hi traderbam...
No...i did not insult Fred......with respect, i suggest the bulk of cutting edge audio today is designed by AES members...eg Robert stuart of Boothroyd- stuart Meridian, who uguably design and manufacture the best all-round, and technically advanced HI-Fi in the world here in the UK.....
However i confess, i do find your accusation of 'plagarism' insulting...indeed defamatory....you of course are incapable of adducing any evidence to back up such an unprovoked piece of scurilous nonsense?
...and as for
'I know you are a confident, budding designer who is getting air-time in an electronics publication and so you are naturally inclined to have the greatest respect for other publicists who preceeded you.
.......please desist from patronising me, as you do not know me at all.....and me you for that matter...
cheers.
Peter writes:
Re the "advertising" bit, I just thought we need to be consistent. Remember poor old AKSA (Hugh) coped a beating around the ears when he first appeared for a lesser indiscretion.
Regards
mark
Not meant to be hostile Peter, if it was interpreted that way, my apology. My concern (primarily) was the thread was being taken away from it's original intent - which I think is an important topic. Your "meander from the path", however pales into insignificance as I read the last 48 hours worth
Re the "advertising" bit, I just thought we need to be consistent. Remember poor old AKSA (Hugh) coped a beating around the ears when he first appeared for a lesser indiscretion.
Regards
mark
Re: Re: cosinusoids...
Except that a Spice simulation is not the same thing as solving
the equations. Spice does a numerical simulation for particular
component values and does not give a symbolic solution, and
being a numerical simulation, a Spice result can never be
trusted unless an error analysis is done.
That said, I agree that Spice is an extremely useful tool. Being
a computer scientist, I do however find a lot of shortcomings
that make it quite tedious to use. That should be possible to
fix, though, by adding an abstraction layer on top of the Spice
engine.
Fred Dieckmann said:
Except that a Spice simulation is not the same thing as solving
the equations. Spice does a numerical simulation for particular
component values and does not give a symbolic solution, and
being a numerical simulation, a Spice result can never be
trusted unless an error analysis is done.
That said, I agree that Spice is an extremely useful tool. Being
a computer scientist, I do however find a lot of shortcomings
that make it quite tedious to use. That should be possible to
fix, though, by adding an abstraction layer on top of the Spice
engine.
Re: Re: Re: Re: Re: VIBERATIONSSSS
I think your setup is reasonable, but to make any experiments
valid you must have somebody else to do the resistor swapping
for you, and this person must try to emulate a random
behaviour, sometimes swapping resistors, sometimes just putting
back the resistors he/she just removed. Preferrably, this person
should also not be visible for you, but if he/she is well aware of
the potential problems when visible, I think it is not necessary.
Peter Daniel said:
You don't know me, then. I like to be practical and this is a simple setup for resistors sound comparison. It takes only few seconds to change resistor so you still have the memory of the sound of the previous one. Of course some will argue that this is not valid setup, because I don't solder resistors and it's outside of the amp so all kind of interferences come in effect. Yet it allowed me to hear repeted and consistant difference with few types of resistors and it was perfectly in line with other forum members. If you will continue to claim that resistors don't have specific sonic signature I simply refuse taking seriously anything you say.
And BTW, I never use inductive resistors.
I think your setup is reasonable, but to make any experiments
valid you must have somebody else to do the resistor swapping
for you, and this person must try to emulate a random
behaviour, sometimes swapping resistors, sometimes just putting
back the resistors he/she just removed. Preferrably, this person
should also not be visible for you, but if he/she is well aware of
the potential problems when visible, I think it is not necessary.
Truly Amazing ........
I thought you guys had been busy a couple of days ago when I checked back in to see what was happening........ WOW!
For raising this topic in this forum, I recall referring to NW as borderline insane and blessed his naive & deluded socks! (Stated in a standard "taking the ****-out" kind of speak, given I'm from Oz, ie no offence intended)
Well, I was right ....... and we now have 20+ pages of proof (for those who like that sort of thing).
I'm not in a position to even remotely argue the "null-test" bit and actually this appears to have received some rational/educated debate.
The discussions around DBRCTs however have departed the realm of all rational scientific thought.
I have NOT stated any of the golden-eared ones will not be able to ascertain a difference between A & B. They may, they may not. However, failure to accept that phychological factors do alter perception seriously undermines the position taken by a number of people.
I am sure there are components which are better (or I certainly bloody hope so!). Reproducibly better and we should define these scientifically, so we may all be confident about what we are talking (and about to spend money on!).
People are (rightly or wrongly) perceiving this statement as an attack on their personal ability (hearing), their system, or their love of HiFi. The resulting slanging matches create images of 4yo children in a sand-pit.
cheers
mark
PS: That was a 2 glass of wine read ..... and opposed to those who say ETOH diminishes the appreciation of Hifi, I say ..... so be it, but it enhances the appreciation of the music
I thought you guys had been busy a couple of days ago when I checked back in to see what was happening........ WOW!
For raising this topic in this forum, I recall referring to NW as borderline insane and blessed his naive & deluded socks! (Stated in a standard "taking the ****-out" kind of speak, given I'm from Oz, ie no offence intended
)Well, I was right ....... and we now have 20+ pages of proof (for those who like that sort of thing).
I'm not in a position to even remotely argue the "null-test" bit and actually this appears to have received some rational/educated debate.
The discussions around DBRCTs however have departed the realm of all rational scientific thought.
I have NOT stated any of the golden-eared ones will not be able to ascertain a difference between A & B. They may, they may not. However, failure to accept that phychological factors do alter perception seriously undermines the position taken by a number of people.
I am sure there are components which are better (or I certainly bloody hope so!). Reproducibly better and we should define these scientifically, so we may all be confident about what we are talking (and about to spend money on!).
People are (rightly or wrongly) perceiving this statement as an attack on their personal ability (hearing), their system, or their love of HiFi. The resulting slanging matches create images of 4yo children in a sand-pit.
cheers
mark
PS: That was a 2 glass of wine read ..... and opposed to those who say ETOH diminishes the appreciation of Hifi, I say ..... so be it, but it enhances the appreciation of the music
nw_avphile said:
Yes unless they effected the differential pair that can cause gain variations outside the influence of the negative feedback loop. Before everybody decides that vibration effects in ICs are impossible, consider that silicon dioxide is commonly used as a passivation layer. The piezoelectric properties are known and put to use in crystal oscillators. Vibration could create noise voltages that are coupled into the semiconductors inside the IC. perhaps even the semiconductor material could have piezoelectric properties
http://www.wikipedia.org/wiki/Piezoelectric_effect
http://www.wikipedia.org/wiki/Quartz
http://www.batnet.com/enigmatics/se...g/CVD_Fundamentals/films/SiO2_properties.html
As for resistors, many of the ones recommended for delusional audiophiles have very low temperature coefficients and voltage coefficients. As the voltage signal changes across a resistor the power dissipated (V squared divided by R) changes the temperature and by proportion to the temperature coefficient; the resistor value. That is the resistor value is changing as a function of signal. This is also related to the thermal mass and thermal time constant of the resistor. A similar effect exist for the voltage coefficient.
It seems that two amplifiers identical expect for the resistors tempco will differ in output as a function of these resistor values dynamically changing with signal. Steady state sine waves are probably poor test signals to demonstrate this with and most of the test discussed may have insufficient resolution to test this effect. The mechanism for distortion is there and who is to say that we cannot hear it in a system of sufficient resolution and listeners with sufficient experience. I guess the guys at the AES have investigated all these effects though.
As for the Crown amp sounding wonderful, you must not have had the levels matched since we know it should sound no better than any other competently designed amp.
Christer, no, nothing has moved much. The last I heard, there were some buffers that I was supposed to receive, but haven't yet. I've located and procured a rather massive multiposition switch for the box. If the "golden ears" think that something like a BUF-03 is an acceptable unit, I do have a few of those laying about which I'd donate to the cause.
I invite the participation of anyone who wants to help out. Specifically, I'm looking for the donation of some "approved" fashion plugs, resistors, and caps (they can even be painted with Tube-O-Later!); besides the switch and the box, I'll happily provide the Radio Shack grade comparison parts.
I invite the participation of anyone who wants to help out. Specifically, I'm looking for the donation of some "approved" fashion plugs, resistors, and caps (they can even be painted with Tube-O-Later!); besides the switch and the box, I'll happily provide the Radio Shack grade comparison parts.
Re: Truly Amazing ........
I absolutely accept that psychological factors do alter perception!
This is a two edged sword that may cut even more sharply in the other direction.
Consider the factors that effect the converse stand.
1. Reliance on the viewpoints of someone whose experience, motivation, listening skills and test methods I have incomplete knowledge. Some of these factors can influence testing measurements even outside situations with subjective factors.
2. Design of a test who's particular outcome is desired to prove an existing exception This should be the biggest red flag for any objective test.
3. Anxiety, time pressure, social pressure, and unfamiliarity with system under test for the test precipitants.
4. Design and resolution of the test system.
I don't understand the assumption that audiophiles are presumed to expect improvements for a given change and that the results of these changes are always assume to be improvements. Doing R and D on audio designs will just as often result in the converse, i.e. It sound worse, it sounds different, it sounds the same. Many of these depend on break-in time, power line conditions and RFI background (very time of day dependent by the way and discussed in non audio literature), source material, add variations in equipment set up, cable and component interactions, and a number of other factors. Almost all of these have scientific and engineering principles behind them.
My biggest problem with a lot of these discussions are the cynical presumptions made about the methodology, motivations, techical abilities, and experience of those who claim to hear differences based on factors outside of mainsteam audio engineering . There are any number of even sharper engineers from other disiplines outside the audio community. I know it is hard to believe, but many other engineering fields even more challenging that audio design. There are contributions from other fields that will advance the art. Siegfried Linkwitz's background at H.P. designing RF and microwave test equipment and its influence on crossover and spearker design is a perfect example. John Dunlevy had a background in antenna design as another example. I believe there are many contributions from areas of science and engineering outside the audio engineering disipline that can make contridutions to the advancement of the art.
mefinnis said:
I absolutely accept that psychological factors do alter perception!
This is a two edged sword that may cut even more sharply in the other direction.
Consider the factors that effect the converse stand.
1. Reliance on the viewpoints of someone whose experience, motivation, listening skills and test methods I have incomplete knowledge. Some of these factors can influence testing measurements even outside situations with subjective factors.
2. Design of a test who's particular outcome is desired to prove an existing exception This should be the biggest red flag for any objective test.
3. Anxiety, time pressure, social pressure, and unfamiliarity with system under test for the test precipitants.
4. Design and resolution of the test system.
I don't understand the assumption that audiophiles are presumed to expect improvements for a given change and that the results of these changes are always assume to be improvements. Doing R and D on audio designs will just as often result in the converse, i.e. It sound worse, it sounds different, it sounds the same. Many of these depend on break-in time, power line conditions and RFI background (very time of day dependent by the way and discussed in non audio literature), source material, add variations in equipment set up, cable and component interactions, and a number of other factors. Almost all of these have scientific and engineering principles behind them.
My biggest problem with a lot of these discussions are the cynical presumptions made about the methodology, motivations, techical abilities, and experience of those who claim to hear differences based on factors outside of mainsteam audio engineering . There are any number of even sharper engineers from other disiplines outside the audio community. I know it is hard to believe, but many other engineering fields even more challenging that audio design. There are contributions from other fields that will advance the art. Siegfried Linkwitz's background at H.P. designing RF and microwave test equipment and its influence on crossover and spearker design is a perfect example. John Dunlevy had a background in antenna design as another example. I believe there are many contributions from areas of science and engineering outside the audio engineering disipline that can make contridutions to the advancement of the art.
Re: Re: Truly Amazing ........
This indeed cand be two edge sword.
Let's assume that somebody takes part in one of those blind tests, yet for some reason it is not performed properly and the individual under test cannot identify the amps. This carries out a psychological effect on him and he starts to believe that all amps should sound the same (and indeed sound the same to him) and spreads the news to everybody he has a chance to. Most people are always on a look out for most convenient belief and this may appeal to many.
I mentioned it yesterday and this is certainly a possibility we cannot deny.
This indeed cand be two edge sword.
Let's assume that somebody takes part in one of those blind tests, yet for some reason it is not performed properly and the individual under test cannot identify the amps. This carries out a psychological effect on him and he starts to believe that all amps should sound the same (and indeed sound the same to him) and spreads the news to everybody he has a chance to. Most people are always on a look out for most convenient belief and this may appeal to many.
I mentioned it yesterday and this is certainly a possibility we cannot deny.
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