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"He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
MLSSA supports a curve fitting algorithm, where measured components can be tested for correlation against ideal componts. Works for resistors, capacitors, inductors, by measuring impedance across all frequencies, then regressing to a curve fit.
Its great for finding wonky caps that otherwise measure fine on a cap bridge, and for inductors than have parasitics.
It's a great tool, it helped find an issue with my Bryston amp and the speaker wire i was using, which led to a change in the amps the output inductor. It was also invaluable to show exacrtly how different speaker cables measure differently, into real loads, with real amplifers.
Using MLSSA, I've never found any issue with resistors, but I'm runing a 8 ohm 50 watt Dale RH through tonight, after the report that they're inductive. I'll let everyone know what I find.
Does anyone have measurements, or links, showing instantaeous temp rise in resistors?
The AES contained many a good article on short term temp rises in voice coils. The pro sound and rigourously objective scientists in their employ felt it to be a large enough issue to publish. I see no reason why resistors wouldn't suffer the same, objectively, especially when they can be consuming watts of power, all wasted as heat (as opposed to loudspeakers where only 99% is heat
These are instantaneous temp rises and not reflected in a noticed temp rise on the surface.
Does anyone have measurements, or links, showing instantaeous temp rise in resistors?
The AES contained many a good article on short term temp rises in voice coils. The pro sound and rigourously objective scientists in their employ felt it to be a large enough issue to publish. I see no reason why resistors wouldn't suffer the same, objectively, especially when they can be consuming watts of power, all wasted as heat (as opposed to loudspeakers where only 99% is heat
These are instantaneous temp rises and not reflected in a noticed temp rise on the surface.
I ran across a paper on Johnson noise in resistors with regards to strain gauge accuracy. I can't remember where. I though it was interesting in that strain gauges are usually associated with very low currents and voltages and was somewhat surprised that resistor noise was such a problem. I'll see if I can find a reference.
Dave
"A man with an experience is never at the mercy of a man with an argument." - Hilmar von Campe
I ran across a paper on Johnson noise in resistors with regards to strain gauge accuracy. I can't remember where. I though it was interesting in that strain gauges are usually associated with very low currents and voltages and was somewhat surprised that resistor noise was such a problem. I'll see if I can find a reference.
Search the world's information, including webpages, images, videos and more. Google has many special features to help you find exactly what you're looking for.
Dave
"A man with an experience is never at the mercy of a man with an argument." - Hilmar von Campe
Search the world's information, including webpages, images, videos and more. Google has many special features to help you find exactly what you're looking for.
Dave
Which of the links in the search is the one you are refering to?
Johnson noise in an 8 ohm resistor, at room temp, over a 20kHz bandwidth (unweighted) is 52nV rms. This is 155dB down from 2.83V rms. Is it possible that this is audible; maybe with bionic hearing?
Which of the links in the search is the one you are refering to?
Johnson noise in an 8 ohm resistor, at room temp, over a 20kHz bandwidth (unweighted) is 52nV rms. This is 155dB down from 2.83V rms. Is it possible that this is audible; maybe with bionic hearing?
Which of the links in the search is the one you are refering to?
*****
I just did a basic search in reply to DDF. Reread the reply to him. I read the article a long time ago. I have better things to do than read all of the unrelated references in my search.
*****
Johnson noise in an 8 ohm resistor, at room temp, over a 20kHz bandwidth (unweighted) is 52nV rms. This is 155dB down from 2.83V rms.
*****
Wiki is a great resource, isn't it?
At what input level? I misused the term Johnson noise to include shot noise. Since the two are interrelated I used the term when referring to transients. I should have used shot noise which is exclusive of the Johnson noise and is comprised of current noise. My bad: a brain fart.
*****
Is it possible that this is audible; maybe with bionic hearing?
*****
I'll have to ask my friend, Patti, with the implant. Perhaps she can tell me.
Dave
"A man with an experience is never at the mercy of a man with an argument." - Hilmar von Campe
well, I was seven years old in the early 80's and I didn't own a CD player until somewhere around 1990 so I missed the whole debate.
You guys are all poopyheads and I have no white papers to back that purely subjective conjecture with so please, just accept my sweeping generalization as a fact. I am a maaintenance man with an AAS in electro-mechanical technology and I have listened to thousands of poopyheads and while they all sound different, they are all poopyheads so there.
Holy cow, I mean it's like we are debating audio properties of something that at normal listening levels probably doesn't matter. It's like discussing saturation of iron core inductors. At normal volumes and power levels is it really a concern? Do resistors in a circuit really get hot enough to change properties at normal listening levels?
I don't know. I got into a debate about wires one night at work with a pair of "audiophiles" who were picking on me for using cheap Dayton interconnects and 12awg zippycord. They used stupid expensive "Transparent" branded stuff. I mentioned that we were running at 99+% repeatability (+/-0.0005mm) on robots using nothing more than Belkin twisted pair cables and grey ribbon cables etc. Oh, and little carbon resistors with a 10% tolerance all over the circuit boards.
FWIW...
It's always refreshing to hear engineers on the front lines debunk a lot of this nonsense. I remember a few years ago a debate about what low quality Toslink connectors were, and how they could audibly degrade the sound. I just had to laugh to myself. At work I was using $40,000 Fore ATM switches that used Toslink connectors. Any dropped or altered bits in those switches would have been a Real Big Deal, but the designers knew there wouldn't be a problem. So much for the ignorant audiophiles.
And yes, anyone who gets sucked into a debate like this is a poopyhead.
"We’ve heard that a million monkeys at a million keyboards could produce the complete works of Shakespeare; now, thanks to the Internet, we know that is not true."
–Robert Wilensky
Yes to A&B - Instantaneous transients (micro to milliseconds: hence the burst of noise) through high power compression drivers are often in the thousands of watts while operating at sustained levels of 50 to 100 watts.
NO to C - they were all Culver ceramic boats. The company that I was doing the repair for had a huge stock of Culvers - crappy resistors, BTW
D - not so much - it's just physics
No, I'm not. I find the Mills, Ohmite, North Creek, and Huntington Electric wirewounds to be my choices. Pretty much I stay away from bulk metals in loudspeaker applications.
I appreciate that. I wanted more info, too. It didn't exist. Fortunately for me it started a whole bunch of "why and how" experimentation and research on my part. Check out my reply to Dave Ellis above. It is a good place to start.
Ah… Very helpful, Dave. I’ve bookmarked the Vishay articles already, but haven’t read the patent yet. Good information, and thanks for sharing.
"I just had to laugh to myself. At work I was using $40,000 Fore ATM switches that used Toslink connectors. Any dropped or altered bits in those switches would have been a Real Big Deal, but the designers knew there wouldn't be a problem."
Really, do you really think the transmitter receivers were the same in that peice of equipment as one might find in a $329 sony dvd player? Were the Toslink connectors a glass conductor or plastic, what grade of plastic? What type of LED and what was its drive circuitry, using the parts in the switch no doubt would triple the cost of an above average DVD player.
Toslink systems in consumer products were measured to have marginal bandwidth to carry a PCM digital signal and to be prone to data loss. Not all toslink systems are built to the same standard. Why did I even have to write that?
At what input level? I misused the term Johnson noise to include shot noise. Since the two are interrelated I used the term when referring to transients. I should have used shot noise which is exclusive of the Johnson noise and is comprised of current noise. My bad: a brain fart.
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Page 324. Shot noise is non existent in resistors with no DC current, the norm in XO circuits, with wire wound being the BEST at reducing shot noise.
Which of the links in the search is the one you are refering to?
*****
I just did a basic search in reply to DDF. Reread the reply to him. I read the article a long time ago. I have better things to do than read all of the unrelated references in my search.
*****
Johnson noise in an 8 ohm resistor, at room temp, over a 20kHz bandwidth (unweighted) is 52nV rms. This is 155dB down from 2.83V rms.
*****
Wiki is a great resource, isn't it?
At what input level? I misused the term Johnson noise to include shot noise. Since the two are interrelated I used the term when referring to transients. I should have used shot noise which is exclusive of the Johnson noise and is comprised of current noise. My bad: a brain fart.
*****
Is it possible that this is audible; maybe with bionic hearing?
*****
I'll have to ask my friend, Patti, with the implant. Perhaps she can tell me.
Dave
Maybe I missed it but I didn't see a spec for shot noise in the Mills resistor data sheet? Some of the other resistor manufacturers do provide a current noise spec of xyz uV/V but not Mills. But even if it turned out to be +10dB for one of the low cost Mills alternatives, that's still 110dB down.
I am always open to learn new things, but so far I still don't see the Mills making an audible difference in a x-over; unless the low cost alternatives are simply horrendous noise generators.
It's always refreshing to hear engineers on the front lines debunk a lot of this nonsense. I remember a few years ago a debate about what low quality Toslink connectors were, and how they could audibly degrade the sound. I just had to laugh to myself. At work I was using $40,000 Fore ATM switches that used Toslink connectors. Any dropped or altered bits in those switches would have been a Real Big Deal, but the designers knew there wouldn't be a problem. So much for the ignorant audiophiles.
Does anyone have measurements, or links, showing instantaeous temp rise in resistors?
I'm not quite sure how this would be relevant if there isn't an audibilty study to go along with it.
Plus measurements are only relevant to the uninformed crowd if they represent a straw to cling to, that might support a belief. If the measurements fail (as always) to support the belief, then they will be dismissed as insufficient and the old fall back of some yet unknown measured parameter (electro-acoustic) is responsible. Of course fMRI's and anything related to the psychology of acoustics will be completely ignored.
The "heard it" (when I see/know/change volume/etc) crowd tales will continue to be told and accepted as gospel by some.
Now if they simply said, hey, I know there is no evidence of change in the soundfield when I add/change widget X in my system, but it affects what I hear anyway, I enjoy it, but there is no guarantee it will affect your brain (as opposed to stereo system) in the same way.
Well, who could argue with that?
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