Just to clarify what we are talking about: this is audio interconnects, up to a few metres in length? If so, assuming good connections at both ends, the cable is a relatively low value capacitor. For good signal transfer, we require a significant impedance mismatch (10:1 - 1000:1) between source and load. The main need is that the source impedance is low enough to drive the cable capacitance, including any non-linearity in that capacitance.
If I am reading these right you have connected the test set to one end of the cable and the preamp output to the other?
One end to the load (amp input or preamp input) the other to the test setup. The setup is for very simple impedance measurements. The interconnect effectively becomes part of the DUT.
Yes, I have no idea what you're testing, what the setup is, what the scale is, what you're measuring.
If you were an idiot, I'd make allowances. But you're not, you're one of the most intelligent guys here. So... if you would be so kind, please fill in the blanks rather than asking for comments about wavy lines with no context. What's the source? What's the signal (waveform, level)? What's the load? What's the scale? What's being varied among all those curves?
If you were an idiot, I'd make allowances. But you're not, you're one of the most intelligent guys here. So... if you would be so kind, please fill in the blanks rather than asking for comments about wavy lines with no context. What's the source? What's the signal (waveform, level)? What's the load? What's the scale? What's being varied among all those curves?
While this is true, if the source does not see a constant load, then you have reactances that effect not only the signal in the cable, but also the feedback of the feeding circuit. Basically this is also a problem with speaker impedance variation.
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What part of this can you not understand?
"... impedances when interconnects are connected to a receiving device" in a longer description it's "measurement of impedance of interconnect and device input impedance as a whole". The information is to show that if you measure equipment input impedance with an interconnect in the measurement path, the result may not be as constant as one expects.
Scale is linear. starting from zero. The important issue is percentage of variation which can be clearly seen from the graphs. Anyone that has been following my measurements for some time know that I use SoundEasy, and the impedance scaling of SoundEasy is linear, as can be discovered through a little bit of searching.
When I come across a similar situation, I'd measure first. As you can tell from many details I have asked about various published papers, I never get enough information. So you expect me to be perfect?
From my point of view, if someone actually does impedance measurements, as conducted with any loudspeaker impedance measurements, and come out with different results, then we start to compare why the differences occur via dialog of setup and test methods etc. As you know, there are too many people just doing lip service, especially in cable threads.
Of course, if anyone in this thread from another country find it worthwhile to fly over here and see, I will demo it.
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Those graphs mean nothing to me, either. What's the scale? How were the measurements taken?
I see variation, but have no reference other than frequency. What's going on there? We don't want perfection, just a frame of reference.
I see variation, but have no reference other than frequency. What's going on there? We don't want perfection, just a frame of reference.
The information is to show that if you measure equipment input impedance with an interconnect in the measurement path, the result may not be as constant as one expects. So, everyone is a afraid of failure to measure impedance? Do some measurements, post it, and we have more discussion.
Pano, vertical scale is linear, if you measure equipment input impedance, what kind of scale you use assume? Come on, you all have been doing this long enough to know what to expect.
Basically, I just went through an Sumiko report, "The OCOS Formula", and started from there. Nothing in terms of measurement setup was explained. The valuable part for me was that they explained the journey with listening impressions from changing various characteristics. They also pointed out the impedance at high frequencies were significantly different from the audio range, with some illustrative graphs even less than I posted. Since I spent lots of time on researching this, I also expect others to contribute their own work before entering any more discussions.
Pano, vertical scale is linear, if you measure equipment input impedance, what kind of scale you use assume? Come on, you all have been doing this long enough to know what to expect.
Basically, I just went through an Sumiko report, "The OCOS Formula", and started from there. Nothing in terms of measurement setup was explained. The valuable part for me was that they explained the journey with listening impressions from changing various characteristics. They also pointed out the impedance at high frequencies were significantly different from the audio range, with some illustrative graphs even less than I posted. Since I spent lots of time on researching this, I also expect others to contribute their own work before entering any more discussions.
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Basically, my measurements of interconnects show similar trend as in the OCOS paper, However, I took a different approach to solve the problem whereas OCOS headed towards speaker cables.
And I also think these arent very useful. What is the scale (values between lines, .01db or maybe micro ohms?) Oh and impedances need phase plots. (with values)
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What's up George? Don't remember what you did? 😉
If that's the case, just admit it. We won't skin you. Don't understand why you won't provide details. The graphs are intriguing, but somewhat meaningless without knowing more.
If that's the case, just admit it. We won't skin you. Don't understand why you won't provide details. The graphs are intriguing, but somewhat meaningless without knowing more.
Call it "temporal loss of memory" if you will, need some stimulus to regain it.😉 Measurements from others can simulate you know.
Tell that to the people that don't believe in audibility of phase shifts.😛 They will say "minimum phase systems ...."🙄
Since it seems that soongsc does not want to answer a very reasonable question, I am happy to make a fool out of myself and make the assumption that the red line on the graph is 75 Ohms.
If I am wrong could you correct me for the benefit of all.
If I am wrong could you correct me for the benefit of all.
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The impedance of all cables I could find information on all end up between 120Ohm to 36Ohm. The OCOS paper explained the transition range is in the higher half of the audio range. We can see this effect in the graphs I posted. Taken this as a known, it should not be difficult to guess the higher end of the impedance is in the category of audio equipment input impedance.
This is just one way I made sense from data that made no sense. Took lots of searching the piles of articles and reports too.
This is just one way I made sense from data that made no sense. Took lots of searching the piles of articles and reports too.
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By "impedance," do you mean "characteristic impedance?"? If not and by "impedance" you mean "impedance," every interconnect I have has an impedance that looks like R - j/wC, with R being on the order of 10-2 and C being on the order of 10-10.
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