Aged Carbon Film Resistors
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GAStan
Member
RG Keen is truly a wealth of experience gained knowledge and an inspiration for how freely he shares it. Thanks @owlexifry for posting that.
@darwin999 very nice write up. I believe you are absolutely right about noise, the science backs it up. I agree with most everything thing said with the exception of your Bottom Line. I respect your opinion but mine differs.
Whether one calls it Mojo or characteristics there are simply too many people that claim to hear the differences between the different types for me to discredit them all. These are differences between the various resistor compositions, different brands of the same composition and even different eras. One theory I've seen is the different audio qualities are due to the different compositions used. One example is the binder in CC Resistors has changed through the years thus the NOS are different than new production-the different sound is due to this rather than age. Another example would be CF resistors. Not only different chemical composition of carbon/binder but also geometry of element's cross section & length-how this can have a effect on the electronic hopping & tunneling you mentioned which in turn can have a subtle effect on the audio signal as it passes through.
Admittedly this is getting deep. I'm simply regurgitating theories I've read in various forums and adding my own embellishment. So what's my point? I feel it's unfair to simply tell everyone to use a single component (resistor, capacitor or whatever) based on a personal opinion. Instead I'd encourage individuals to experiment and form their own opinions.
It's my opinion that many (not all due to some seeking personal gain) people claiming to hear differences in using different components actually hear them. I feel that the technology simply does not exist yet to prove these differences scientifically.
@darwin999 very nice write up. I believe you are absolutely right about noise, the science backs it up. I agree with most everything thing said with the exception of your Bottom Line. I respect your opinion but mine differs.
Whether one calls it Mojo or characteristics there are simply too many people that claim to hear the differences between the different types for me to discredit them all. These are differences between the various resistor compositions, different brands of the same composition and even different eras. One theory I've seen is the different audio qualities are due to the different compositions used. One example is the binder in CC Resistors has changed through the years thus the NOS are different than new production-the different sound is due to this rather than age. Another example would be CF resistors. Not only different chemical composition of carbon/binder but also geometry of element's cross section & length-how this can have a effect on the electronic hopping & tunneling you mentioned which in turn can have a subtle effect on the audio signal as it passes through.
Admittedly this is getting deep. I'm simply regurgitating theories I've read in various forums and adding my own embellishment. So what's my point? I feel it's unfair to simply tell everyone to use a single component (resistor, capacitor or whatever) based on a personal opinion. Instead I'd encourage individuals to experiment and form their own opinions.
It's my opinion that many (not all due to some seeking personal gain) people claiming to hear differences in using different components actually hear them. I feel that the technology simply does not exist yet to prove these differences scientifically.
JTEX
Well-known member
^ oh yes, the technology (and methodology) to prove/disprove audio perception very much exists. The problem is that people often don't want to accept the results if they contradict their preexisting ideas. If you think something sounds good, or different from something else, then it will sound so to you. We do audio research at work all the time, so I get to see lots of experiments. I've even personally fooled people into being convinced they heard something when I knew very well that I just pretended to change something.
Nostradoomus
Well-known member
GAStan
Member
People can be fooled, no doubt, especially when it's your intention to fool them. Alan Funt did this time after time... But proving a person, or even a group of people, can be fooled doesn't prove that no one can hear differences between various components. You proved you can easily fool another person, does this mean you can be fooled just as easily? Can we laugh at you when it happens? 
I was actually referring to the technology to analyze audio signals to the point very subtle differences can be distinguished and documented, taking the human factor out of it. For example tones described as smooth vs grainy, thick vs thin, clean vs muddy etc. How would you scientifically document these things and distinguish them from one another? What do these look like on something like an o'scope, spectrum analyzer or ??? Maybe we have the data collection capability but just need the appropriate algorithm, filter, comparator or some other software to analyze it. I understand (kinda) these concepts but am definitely getting out of my comfort zone so I'll leave it here.
I was actually referring to the technology to analyze audio signals to the point very subtle differences can be distinguished and documented, taking the human factor out of it. For example tones described as smooth vs grainy, thick vs thin, clean vs muddy etc. How would you scientifically document these things and distinguish them from one another? What do these look like on something like an o'scope, spectrum analyzer or ??? Maybe we have the data collection capability but just need the appropriate algorithm, filter, comparator or some other software to analyze it. I understand (kinda) these concepts but am definitely getting out of my comfort zone so I'll leave it here.
spi
Well-known member
Chase tone sells a good pedal at a reasonable price, but the copy on the web page does seem very snake-oilish.
But, it does look like they have used carbon film before too, so it could just be that they've switched it up and didn't change the page.
JTEX
Well-known member
Rest assured that audio can be analyzed way, way beyond any human's ability to hear, just as technology obviously exists to see tiny things far beyond what the human eye can see. Now, how that translates into terms like "this sounds thin, or grainy" or such, I don't know. These terms are subjective.
And yes, anybody can be fooled, myself included of course. I've even accidentally fooled myself many times. Nobody is immune. And it's extremely hard to prove that something does not exist. If I say there's a ghost in my closet, how can anyone disprove it? I think the onus is on somebody who makes a big claim to prove it... bigly.
GAStan
Member
Yes I do understand we currently have a big capability of analyzing audio, but aren't there advances made frequently that continually advance our capability?
And about the fooled, reading it again i can see how it could be taken as an attack, it was not intended that way and I apologize if it was. I was just trying to make a point. I've been known to make a fool of myself on occasion.
This is exactly the point I'm making. Another way of thinking about subjective is that it cannot be measured- yet. Just because something cannot be measured today doesn't mean it cant be tomorrow. Think about it, how many things in the past were considered subjective before they could be measured?
And about the fooled, reading it again i can see how it could be taken as an attack, it was not intended that way and I apologize if it was. I was just trying to make a point. I've been known to make a fool of myself on occasion.
darwin999
Well-known member
Years ago one of the stereophile magazines did tests with known/renown golden eared people - e.g., famous professional musicians, recording engineers, etc. What they found was that these people could hear distortion switched in/out at low levels (say .05-0.1%) for a single frequency pure sine wave. But in more complex music with multiple instruments playing, popular as well as classical, these same folks could frequently not detect as much as 10% distortion being switched in/out. And for ordinary folks, the distortion levels that could be detected were much higher.
In addition, psychoacoustic experiments have repeatedly found that very slight changes in overall volume are much more readily detected by the ear than small differences in distortion or even frequency response. Note that such small volume differences are frequently not interpreted by the listener's brain as louder vs softer, but more typically as just different somehow, or maybe slightly better vs worse. Hence any acoustical comparison experiments (e.g., for mojo vs non-mojo, etc) have to work very carefully to match the 2 volumes very closely.
Finally, for tests to unambiguously demonstrate a difference, the listener has to be unaware of which source they are listening to (e.g., mojo vs non-mojo, or whatever) with multiple random listenings - and afterwards be able to identify which was which with high probability.
In light of these known issues, I still find it very difficult to believe that someone could hear the ~0.1% distortion of a carbon resistor driven way beyond its rated voltage when that same signal is also passing through multiple tubes which are generating ~10% distortion.
And by the way, I also agree that we're all sharing views here, and I don't feel that anybody is being aggressive - i.e., it's a good and fair discussion.
In addition, psychoacoustic experiments have repeatedly found that very slight changes in overall volume are much more readily detected by the ear than small differences in distortion or even frequency response. Note that such small volume differences are frequently not interpreted by the listener's brain as louder vs softer, but more typically as just different somehow, or maybe slightly better vs worse. Hence any acoustical comparison experiments (e.g., for mojo vs non-mojo, etc) have to work very carefully to match the 2 volumes very closely.
Finally, for tests to unambiguously demonstrate a difference, the listener has to be unaware of which source they are listening to (e.g., mojo vs non-mojo, or whatever) with multiple random listenings - and afterwards be able to identify which was which with high probability.
In light of these known issues, I still find it very difficult to believe that someone could hear the ~0.1% distortion of a carbon resistor driven way beyond its rated voltage when that same signal is also passing through multiple tubes which are generating ~10% distortion.
And by the way, I also agree that we're all sharing views here, and I don't feel that anybody is being aggressive - i.e., it's a good and fair discussion.
Feral Feline
Well-known member
Even better than tweaking knobs that do nothing, if you only have fully-functional knobs at your "disposal", is to systematically adjust each knob a little, and after tweaking three different knobs go back to the first knob and tweak it back towards what it was... keep "compensating" for the interactiveconnectedness of the knobs until after, say three full run-throughs, you are back to EXACTLY where you were before.
Even somebody watching closely can't follow the shell game, I mean they're not cats, after all.
Okay... Three was too easy... bump it up a notch:
Even somebody watching closely can't follow the shell game, I mean they're not cats, after all.
Okay... Three was too easy... bump it up a notch:
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JTEX
Well-known member
Very true. When doing psychoacoustic experiments we go to great lengths to match levels very accurately (to small fractions of a dB). Louder is almost always perceived as sounding better - even if it's the exact same source, just played 0.5dB louder.
Consider that a great studio speaker (costing thousands of dollars) easily has something on the order of 1% distortion. That, and the room itself, are the weak points of the audio chain.
GAStan
Member
With all of this in mind I have to think distortion is not the cause of the difference they are hearing. Then what is the cause? I'm at a loss. I was thinking maybe the resistors have some capacitance or inductance that was a possible cause. So I got out my (relatively inexpensive) LCR meter and tested several. It indicated negative values for both farads and henries. This doesn't prove the resistors don't have capacitance or inductance, a zero value I would have believed. A negative value leads me to believe it is beyond the meters capability.
So I'm really at a loss. This discussion has taught me a lot, I'm grateful to everyone that has participated. The logical side of me leans toward "no difference other than noise level". My gut tells me there is more to be found on this. Either way I'm not willing to say I don't believe those that say they can hear a difference.
So I'm really at a loss. This discussion has taught me a lot, I'm grateful to everyone that has participated. The logical side of me leans toward "no difference other than noise level". My gut tells me there is more to be found on this. Either way I'm not willing to say I don't believe those that say they can hear a difference.
darwin999
Well-known member
Those negative values are likely resulting from your meter having a small phase error when looking at the impedance, which is overwhelmingly dominated by the huge real resistive component - the imaginary impedance (due to any capacitance and inductance) is tiny by comparison at audio frequencies except maybe for the highest resistors (e.g., multi-Mohm and beyond). In RF frequencies, a resistor's L & C matter. At GHz the whole world looks like 10-100 ohms, lol.
Agreed. I may have my doubts, but who am I to say what others can do? I'd just like the test to be well constructed - so that if they do hear something, it would be conclusive.
It's so easy to fool yourself! And I agree that slight changes in volume are more easily detected than actually tonal changes. Often just raising the volume a tiny amount sounds "better". I often build two pedals at a time when I'm trying to tweak something to sound more to my liking. I will build them identically (within tolerances of course) and modify one so I can compare it to the unmodified one to see if there is actually any improvement. Our memory of sounds is unreliable! Usually which circuit is louder sounds better.
When I build pedals I always use metal film resistors. But in amps I use CF for most of the amp, with metal oxide for those under more load. I have to admit that this is mainly because metal film in an amp look wrong to me! But I don't seem to have any issues with noise or failure with the CF resistors. I'm quite tempted to use those red Vishay MFs in my next build though - they look cool.
When I build pedals I always use metal film resistors. But in amps I use CF for most of the amp, with metal oxide for those under more load. I have to admit that this is mainly because metal film in an amp look wrong to me! But I don't seem to have any issues with noise or failure with the CF resistors. I'm quite tempted to use those red Vishay MFs in my next build though - they look cool.
