Just curious, how is a coal listening test organized? I can see a bunch of audiophiles slowly bringing pieces of coal from various mines close to their ears and concentrating, but I'm not sure I got it right.
Many decades ago when telephone meant carbon microphone, Bell Labs did the kind of study they did best, and bought an ENTIRE coal mine (one of its many shafts) to provide coal for microphones.
For them "sound" meant "doesn't pack down and short out", not "airy wood flute tone". And likely "little corrosion of metal contacts". (Coal tends to Sulphur which tarnishes metals.) By some standards, all carbon mike suck bad. But apparently they could suck worse if the coal was not controlled.
^This is the sort of off topic, interesting post from a knowledgeable person I meant, I hope the thread isn't closed down merely due to the posts of those who desperately want to drag it back on topic.
Jan,
I take it you never played the game around here called “Telephone.” You had a line of children and you whispered something such as “The sky is blue” to the first in line and they then whispered the phrase to the next in line and that continued until the last one would then announce what they heard such as “Skylar is unhappy.”
Here the game was to start with a post and watch how it got interpreted and changed as folks responded to the drifting theme.
You apparently stopped folks from testing coal by banging on it or some such other silly result!
What fun is that? If folks actually wanted to be precise and informed, they could actually follow or even read the thread.
It is far more interesting in what should be a dead thread to inject a nonsense life into it! 😉
Oh and Bill you are still a glozerating phlumpshaw, but now you have company.
I take it you never played the game around here called “Telephone.” You had a line of children and you whispered something such as “The sky is blue” to the first in line and they then whispered the phrase to the next in line and that continued until the last one would then announce what they heard such as “Skylar is unhappy.”
Here the game was to start with a post and watch how it got interpreted and changed as folks responded to the drifting theme.
You apparently stopped folks from testing coal by banging on it or some such other silly result!
What fun is that? If folks actually wanted to be precise and informed, they could actually follow or even read the thread.
It is far more interesting in what should be a dead thread to inject a nonsense life into it! 😉
Oh and Bill you are still a glozerating phlumpshaw, but now you have company.
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What is the problem here? All the serious audio designers I know have chosen which resistor types sound best in their equipment. Just because some diy amateurs don't want to bother is their choice. As long as they don't subject their own equipment to open listening tests, no contest.
I would like to relate a listening experience from over 40 years ago that got me taking resistor brands and types seriously. At the time, I was consulting for different companies and I wanted to experiment with a new phono stage design, a new volume control, etc, yet keep the line stage about the same as the previously successful Levinson JC-2 line stage. I had pre-built modules that I could use, in order to keep everything possible as consistent to the successful Levinson JC-2 as possible. At the time, I had evolved, over more than a decade, from Allen Bradley baked carbon resistors (Ampex favorite) to misc 1% metal film resistors like Owens Corning, etc resistors, just like Levinson used, but then I found surplus resistors that were even MORE precision (typically 0.1%, sometimes better), in really fancy packages, some really elegant, and typically with gold plated leads. Well these resistors should be at least the same or superior quality to my previous selections, so I used them. Guess what? Even the line stage only, using Levinson built modules sound lousy! How could this be? The only real difference was these super fancy precision resistors (I still have many many of them today) so I was forced to conclude that it was these resistors that were the problem. I went back to 1% Corning, Dale etc. with good success. Then a few years later, 'Hi Fi News' published the article on resistor differences, and I was given more evidence.
Now, this resistor difference controversy has appeared on this website before, and at the time I sampled both Jan Didden and I think Scott Wurcer with the suspect resistors that I am pretty sure were problematic, but I got no feedback from either of them, so who knows? Some of us just try different resistors, some of us also 'deeply' measure them, like Ed Simon has, as well, but serious audio designers take resistor differences seriously.
Now, this resistor difference controversy has appeared on this website before, and at the time I sampled both Jan Didden and I think Scott Wurcer with the suspect resistors that I am pretty sure were problematic, but I got no feedback from either of them, so who knows? Some of us just try different resistors, some of us also 'deeply' measure them, like Ed Simon has, as well, but serious audio designers take resistor differences seriously.
I always thought carbon resistors are made out of synthetic carbon powder, sintered into cylindrical shapes and having metal terminations attached. But there’s a distinct possibility that true audiophile carbon resistors are made out of coal extracted from a deep mine in a secret location. A trained audiophile could easily distinguish these from fakes manufactured from coal lumps extracted in the Black Thunder mine, Wyoming.
Look at post 194 image 3. That is not very pure carbon. Amazingly enough only one other manufacturer has almost the same results. But the outer casings do not match.
Making coke from coal is still done. I don’t mean coca-cola.
Making coke from coal is still done. I don’t mean coca-cola.
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Ed,
The vertical scales in those imaqes say dBr.
So what voltages were applied, only in the fifth image I see 15.81V and 7.59V but the other four images don't mention and what resistor was used in series with the DUT or was it twice the same.
The A below dBr, does this mean A weighted ?
The fourth image has no further information at all.
Hans
P.S. And yes, you can dissolve coke into coal and extract it after transport, an unfortunate industry that's flourishing in the Netherlands despite all efforts to stop it.
I´m quite certain he does not mean that kind of "coke" but the real, Industrial one.
Which is extracted from common mined coal.
Coke | coal product | Britannica
All resistors tested at the same voltages. If you mouse over the thumbnail it shows the title which is the resistor type. That bad result image is an Ohmite 1/2 watt resistor as noted.
The article Jan posted has all the details on my measurement method.
The “A” just means one of the FFT analyzers inputs.
Jim,
You saved a lot of folks from having to Wiki “coke!” The picture you posted is of a “pour”. The furnace, converter or whatever turns the iron ore into molten steel, empties into the bucket shown. The bucket can actually hold the output of several furnaces to pour bigger things.
The pour in some plants goes into a mold to make an ingot that when cooler can be rolled into a sheet or some such as needed.
The modern steel mills use a process called continuous casting. Kind of self explanatory.
Also most steel today is not made from iron ore but rather recycled steel often with just a bit of new ore added in.
The article Jan posted has all the details on my measurement method.
The “A” just means one of the FFT analyzers inputs.
Jim,
You saved a lot of folks from having to Wiki “coke!” The picture you posted is of a “pour”. The furnace, converter or whatever turns the iron ore into molten steel, empties into the bucket shown. The bucket can actually hold the output of several furnaces to pour bigger things.
The pour in some plants goes into a mold to make an ingot that when cooler can be rolled into a sheet or some such as needed.
The modern steel mills use a process called continuous casting. Kind of self explanatory.
Also most steel today is not made from iron ore but rather recycled steel often with just a bit of new ore added in.
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Ed,
Following 12dB 3rd harmonic increase per voltage doubling that you mentioned, and assuming a 1V voltage from the OP's CD, this alone would already mean a decrease of 36dB in THD compared to your 7.9V test voltage.
Added to that, the 22K OP's resistor instead of 1K would result in another drop of 54dB following the same line of reasoning, giving a total of 90dB lower 3rd harmonic distortion as in your graphs.
Even for the worst of them all, the Ohmite carbon, this would result @1Khz in -190dB or 0.3nV 3rd harmonic, a value that will completely disappear in the noise RTI from the OPA1656.
At 100Hz this would be sqrt(1k/100)*0.3nV = 1nV, still insignificant.
To conclude: supported by your graphs, there is no way to explain sound differences in the OP's preamp for various resistor types unless:
1) He is telling fairytales, or
2) The used circuit is not unconditionally stable as is the case in this thread for the same OPA1656.
OPA1656 Phono Preamp: Split from OPA1656 thread
Hans
Following 12dB 3rd harmonic increase per voltage doubling that you mentioned, and assuming a 1V voltage from the OP's CD, this alone would already mean a decrease of 36dB in THD compared to your 7.9V test voltage.
Added to that, the 22K OP's resistor instead of 1K would result in another drop of 54dB following the same line of reasoning, giving a total of 90dB lower 3rd harmonic distortion as in your graphs.
Even for the worst of them all, the Ohmite carbon, this would result @1Khz in -190dB or 0.3nV 3rd harmonic, a value that will completely disappear in the noise RTI from the OPA1656.
At 100Hz this would be sqrt(1k/100)*0.3nV = 1nV, still insignificant.
To conclude: supported by your graphs, there is no way to explain sound differences in the OP's preamp for various resistor types unless:
1) He is telling fairytales, or
2) The used circuit is not unconditionally stable as is the case in this thread for the same OPA1656.
OPA1656 Phono Preamp: Split from OPA1656 thread
Hans
My post #203 describes a cause for the diode effect, did that cover it well enough, or do we need to dig into all the other unrealistic mechanisms with another 200 or so posts?
Yes, the entertainment value of this thread is priceless. I particular when certain members are taking it seriously.
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