There are IRE papers from 1952/53 about vectorscopes and the problems seem to have been well known already then.
TIM was discovered in an off comment in 'Wireless World' around 1952. The first bipolar transistor was accidently discovered by a radio amateur in 1938 or so. And so it goes.
Hi John,
The bipolar junction came to light in 1948 as far as I know.
-Chris
Not Bell labs in 1947 by John Bardeen and Walter Brattain while under the leadership of William Shockley? This would have been a point contact type germanium type back then.
The bipolar junction came to light in 1948 as far as I know.
-Chris
It just goes to show how you can't know everything. An amateur reported making a dual point contact device with gain in the late 1930's. It just didn't survive the intense scientific demands to duplicate it at will, so it was forgotten.
A bit off the topic of phase shift with level change but interesting, I have seen a syncroscope from a bit earlier. With a bit of bother you could use a vectorscope for measuring phase shift with level. But it really was interesting to see how Color Phase Modulation really exposed a lot of weak links.
Of course if you ever have sat in a control room very early at any major televised event you could watch all the cameras zoom in on the same woman's white blouse, so they could all be "white balanced" the same! The "engineer" at the truck or control room would adjust to get the same color from all of the cameras to compensate for the slightly different phase shifts due to cable length differences, etc. Yes they still had vectorscopes, but which would you rather look at?
Ed, just read your 'Power Amp Kits for Beginners' article. The resistor measurement is very interesting (Fig. 3, Fig. 4). The fundamental is notched, right?
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Ed Simon is quite a researcher in his spare time. Kind of like you and me, PMA.
I rely on him these days for (mythological) resistor differences that can't be detected in double blind tests, but can be measured with some effort and sophistication.
I have some absolutely 'beautiful' glass cased resistors here of perhaps .1% precision that for some reason, sound lousy or at least my 'biased' ears think so. It would be interesting how they measure differently (or not) at some level well below the established and peer review accepted limits of human hearing as we know it today.
All hail OHM's LAW! (of acoustics and resistance)
I rely on him these days for (mythological) resistor differences that can't be detected in double blind tests, but can be measured with some effort and sophistication.
I have some absolutely 'beautiful' glass cased resistors here of perhaps .1% precision that for some reason, sound lousy or at least my 'biased' ears think so. It would be interesting how they measure differently (or not) at some level well below the established and peer review accepted limits of human hearing as we know it today.
All hail OHM's LAW! (of acoustics and resistance)
I think most of us can agree to that. It has been said here often, and AFAIR, not really contested, that measured data like THD and what have you is not a good indictaor of success in the market place.
In fact, it is glaringly obvious: if you look at successfull products in the market, you see anything from SE tubes to complex solid state push-pull/bridged, from zero global feedback to extremely high feedback.
And all have a faithfull set of followers swearing theirs are the best, yet they have wildly differing measured parameters. So, yes, measurements and market succes are two (very) different animals.
jan didden
Hi John,
Well, resistance isn't always a constant as you know. If such a part is located in a circuit location sensitive to this, you'll hear it. As you say, it can also be measured if some thought is given on how to go about testing the part.
It's amazing how often things can be settled or learned if you just sit down and experiment. That's also the fun in electronics.
-Chris
Well, resistance isn't always a constant as you know. If such a part is located in a circuit location sensitive to this, you'll hear it. As you say, it can also be measured if some thought is given on how to go about testing the part.
It's amazing how often things can be settled or learned if you just sit down and experiment. That's also the fun in electronics.
-Chris
No, not all. That is why we have audio reviewers, you know, in an ideal world, golden eared, earnest seekers of audio excellence. High end audio doesn't run in circles as everyone here proclaims. It evolves, yet it sometimes redescovers some audio approach forgotten for practical reasons, usually, that still has some real merit, such as electromagnet speakers rather than fixed magnet driven speakers. There was nothing wrong with the former, and in the 1930's it was standard stuff. Alnico 5 magnet material made speakers cheaper and easier to wire up, especially remotely, and electromagnet speakers were mostly forgotten. If someone brings back this design, it is for its intrinsic properties, forgotten in the rush to make things cheaper and more practical.
The very idea that resistance is NOT constant! ;-) And even if a resistor isn't perfect, we know that a double blind test will show that it isn't really audible. Isn't that what has been proved over and over, by REAL ENGINEERS, who even write books condemning the subjective audiophiles to mass delusions?
That is as bad as the ear hearing monaural phase. All hail Paul Klipch! He at least stuck to Ohm's law (of acoustics)
That is as bad as the ear hearing monaural phase. All hail Paul Klipch! He at least stuck to Ohm's law (of acoustics)
Oh yes, I agree completely. What is quite interesting, is the coincidence of slew rate and CCIF IMD 19+20 or 13+14kHz. In case you measure OPA627 vs. 637, you will get same THD at 1kHz, BUT different CCIF. The faster part (higher SR) measures better in a CCIF test.
Here we go again, resistors tested at 1/4 - 1/2 their rated power and then, "that must be why they don't sound good as a phono termination". I hope some folks see the false reasoning going on. Not to mention that there is no evidence offered that these sub-ppm distortions have to do with anything in the first place.
Who ever claimed that all resistors have 0 TC?
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As many of us know, many components in the world of electronics are made with junctions, because it is necessary to attach different material structures, many often made elsewhere together, to make a useful part. In the case of resistors, lead wires of some metal have to be attached to a conducting substrate of carbon, some sort of metal alloy, etc. These connections are sometimes difficult to make, and expensive too. Now, these connections might be OK at highish levels, but are they just as good at lowish levels. What about 1uV? What about 1nV? Is EVERY available resistor virtually perfect at 1uV? Do connections, often made the cheapest possible way, always work perfectly at really low levels? What about solder joints? Are they even better than most connections? If so, why does the military often demand that connections be welded, rather than soldered? What about relay contacts, and switches? Will the Radio Shack level 2A switches do for moving coil cartridges switchable inputs? If not, why?
Now, I have asked many questions, and have answered them to my own satisfaction. It took a lot of time to get these answers to the point where I can make better than average quality (still not necessarily differentiatable in a double blind listening test) designs, that people seem to hear as better than many other designs, that often have more features. At least, this is what people tell me.
Now, I have asked many questions, and have answered them to my own satisfaction. It took a lot of time to get these answers to the point where I can make better than average quality (still not necessarily differentiatable in a double blind listening test) designs, that people seem to hear as better than many other designs, that often have more features. At least, this is what people tell me.
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