But surely there exists data (such as 1/4W 1% metal film resistors in 200W power amplifier feedback paths) that suggests thermal modulation effects are orders of magnitude lower at audio frequencies? (Note that I am not saying I would prefer to use a 1/4W there in my best amplifiers, just that the data exists and has meaning.)
When you did your tests what did you do to distinguish between different sources/types of distortion? Why do you think you it is thermal modulation related distortion and not something else such as voltage coefficient as an example? How did you prevent an erroneous attribution of cause to the experimental effect that you observed?
There are many pieces of low distortion gear that use 1/4W 1% metal film resistors and often smaller SMD exclusively. (I am not advocating that and I like to be more conservative in critical parts of my designs, but never the less such gear and tested/verified specifications exist.)
Not that complex. I referred to Ed Simon's measurements (see also his article, attached) that compare distortions of various resistors. Again, you can get into a situation where a resistor in the feedback path has more distortion than the rest of the carefully designed amplifier.
How/what is audible is another kettle of fish of course; I am generally very skeptical about audibility reports from people with a stake in the outcome, so refrain from commenting on specifics.
Jan
How/what is audible is another kettle of fish of course; I am generally very skeptical about audibility reports from people with a stake in the outcome, so refrain from commenting on specifics.
Jan
I would agree that resistors are among the least of the problems in audio reproduction. In other words they are pretty well understood.
In addition we know that sometimes people imagine hearing things that aren't real.
What I object to is when some EEs assume that reports of resistors, caps, cables, etc., affecting sound must be imaginary or else lies if there is little or no associated HD, or if noise on an FFT looks low enough. IMHO they put more reliance on AP machines than is warranted.
For that reason I would prefer that we try to avoid jumping to conclusions when someone like the OP of this thread reports hearing some difference. People have been falsely accused of lying, selling snake oil, or imagining things when they actually did hear something real. That includes John Curl's opinion that Bybees could affect sound in some cases, although not in way that Bybee advertised, and not in the ways that you debunked.
In addition we know that sometimes people imagine hearing things that aren't real.
What I object to is when some EEs assume that reports of resistors, caps, cables, etc., affecting sound must be imaginary or else lies if there is little or no associated HD, or if noise on an FFT looks low enough. IMHO they put more reliance on AP machines than is warranted.
For that reason I would prefer that we try to avoid jumping to conclusions when someone like the OP of this thread reports hearing some difference. People have been falsely accused of lying, selling snake oil, or imagining things when they actually did hear something real. That includes John Curl's opinion that Bybees could affect sound in some cases, although not in way that Bybee advertised, and not in the ways that you debunked.
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You've said this many times before. Who are you referring to? Or are you just trying to insult everyone who uses science as part of product development?
I'm not sure that what Scott meant in regards to coaching poeple and what you mean above is the same thing, but shouldn't the blind testing you describe show if a difference exists anyway?
Of course not.
I am referring to the ill treatment of people reporting what they hear. The ridicule, the name-calling, the smug superiority, all that stuff.
Mark, you have lots of experience in audio, technically as well as listening. When you read the 1st post here, do you then think: 'wow, maybe there's something to this resistor stuff'?
Having an open mind for things we are not certain about is one thing, but taking such extreme statements serious* is far beyond 'an open mind'.
As they say, extraordinary claims require extraordinary proofs.
*I do not dispute that the OP is convinced he heard what he reported.
Jan
I assume you are referring to the attach graph where there appears to be a 2 or 3 dB difference in HM3 for a 4x change in frequency? (I wonder if a 4x change in frequency should correspond to a larger difference?)
It says:
Any idea of the brand and series used for the test?
Were any other multiple frequency tests done? (On the other resistor types?)
Attachments
It depends on what the experimenter is looking for.
Basically there is nothing wrong with training listeners on a specific direction/dimension if one wants to find corrobation for the audibility of a certain sound effect.
Of course, this way the experimenter might miss other effects he wasn't aware of before, but to find each and every perceptable difference could be simply another task.
@jan.didden;
We are all biased and what we consider as extraordinary reflects mainly our biases.
IIRC Martin Colloms did a similar resistor shootout a long time ago, even using some blind test routines, but wrote only in short snippets about the sound impressions and tests but in no way sufficiently detailed to allow replications.
Definitely.Shouldn't this thread being merged with the Funniest Snake Oil theories one? I think all has been said there yet.
Best regards!
Throw the UFO threads there too
And any and all containing the dreaded "you can´t prove ME wrong!!!!"
well reading the OP where he says of one resistor
Bruno's open source balanced preamp design uses MELFs on the input. Horrid things to work with (IMO) but they were there for a reason as 0.1% tolerance and good tracking were needed to maintain CMRR.
That is pretty much impossible to parse. And frankly unbelievable for changing the input resistor.
Bruno's open source balanced preamp design uses MELFs on the input. Horrid things to work with (IMO) but they were there for a reason as 0.1% tolerance and good tracking were needed to maintain CMRR.
The Dale MF 25PPM RN65E in post #194 appear to show a much greater difference (perhaps 10 dB)?
The "Naked" Vishay perhaps 4 dB.
So the unnamed "inexpensive" resistors seem to have the least temperature modulation (2-3 dB, but higher distortion).
Do you recall what series/brand the "inexpensive" resistors were?
I wonder if the apparent difference between these measurements and the theoretically expected thermal modulation is due to the time constants. (Or more specifically the wrong/inappropriate time constants.)
Perhaps the time constants that are provided are related to heating the entire resistor body (ceramic core) and perhaps they are geared towards reliability.
For thermal modulation induced distortion perhaps it is necessary to look at how quickly the thin metal film on the surface of the ceramic heats up, not the whole body. Perhaps analogous to how long it takes the active transistor site in the die to heat as opposed the heatsink reaching a steady state. (And perhaps related to the reason for the ON ThermalTrak devices and the Sanken SAP15N/SAP15P.)
You would have been taken seriously if you replied "As I have demonstrated via objective method before". Hearsay doesn't carry weight no matter how many times it's uttered.
It would be perfectly acceptable if the claim is about perceiving some difference or actually did perceive something. Whether the difference the person perceived is actually audible or not comes after investigation, not at the moment the perception occurs.
Those who try to shill for snake oil get called out. You can just ignore them or stop shilling for such business if you don't like the treatment.
Probably, to an extent. That is to say, I don't think its always imaginary. Also, I would like to be there when someone is doing their experiment if I am going to be a critic. If I can't be there then I would at least like to pics of the experimental setup, a list of all the equipment used, and whatever other information is available. Just don't like jumping to conclusions when information is sparse. There have been times in the past when I did jump to conclusions and later turned out to be wrong. Eventually found out what Daniel Kahneman knows: 'The human mind is a machine for jumping to conclusions.'
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