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Hans Polak
diyAudio Member

Join Date: Mar 2005
Location: Blaricum
Quote:
 Originally Posted by danny_66 Hi Hans, how do you calculate the values of the LCR ?
Hi Danny,

In short:
To start with, measure with a VNA the open and shorted impedance of the cable.
This gave me resp the inductance and the capacitance of the 2.5meter 4mm^2 cable, resp 1.5 uF and 150pF. With sqrt(L/C) this confirms Zo=100R.

Now to get Zo=4R such as in my case, from 4=sqrt(1.5uHu/C) it can be calculated that C must be 93nF, so divided over 3caps gives 31nF per cap.
When simulating Zo in LTSpice, you will find that you still need a resistor and a coil in series with the cap, of resp 600nH and 9R, but taking into account the 150nH and 1R that the cap has, I needed resp. 450nH and 8R.
Be aware that these inserted LRC components better be able to withstand a few Amps to prevent added distortion.

Hans

Hans Polak
diyAudio Member

Join Date: Mar 2005
Location: Blaricum
Quote:
 Originally Posted by peufeu Does anyone know what's inside the mystery boxes on this MIT cable?
Sorry, I forgot the image.
Here it is.

Hans
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Hans Polak
diyAudio Member

Join Date: Mar 2005
Location: Blaricum
Quote:
 Originally Posted by planet IX I would gladly repeat this experiment, but my speaker cables need to be a bit longer. So should I repeat the network any 0,625 meters?
What cables do you have and how long are they ?

Hans

 10th June 2021, 11:09 AM #234 planet IX   diyAudio Member     Join Date: Mar 2004 Location: Colonia Claudia Ara Agrippinensium At present I use a solid-core cable 2*1mm˛ (originally Siemens Profibus, I think) I guess its 3-3,5m long, I can check it this afternoon. I could also measure the impedance,as you described above. I had MIT cables in the 90s, also some other not so cheap cables (Kimber, van den Hull). But then I once tried solid core cable (there are hunderts of meters in the Opt of my Tubeamp, was my thinking, so it coulnd't be that bad) and ever since then I use solid core loudspeaker cables. But I'm always open for new expereiences...
 10th June 2021, 11:23 AM #235 Hans Polak   diyAudio Member   Join Date: Mar 2005 Location: Blaricum Ok, when I know the inductance and the series resistance, I can do the calculation for you. Hans
danny_66
diyAudio Member

Join Date: Jun 2005
Location: Lierde
Quote:
 Originally Posted by Hans Polak To start with, measure with a VNA the open and shorted impedance of the cable.
Thanks for the guide.
A VNA is missing in my toolbox,
there are some cheap VNAs on ebay/banggood/Ali, what are the specs I should be looking for in a VNA ?
__________________
My RefSpeaker v2

 10th June 2021, 01:02 PM #237 Hans Polak   diyAudio Member   Join Date: Mar 2005 Location: Blaricum Can you give me a link to such Alibaba device. I’ll have a look at it and give my comment. But you can also do a inductance measurement with the cable shorted at the other side. And in the same way you can measure the DC resistance. Those two parameters are the most important. Hans Last edited by Hans Polak; 10th June 2021 at 01:05 PM.
 10th June 2021, 01:12 PM #238 1audio   diyAudio Member   Join Date: Mar 2004 Location: SF Bay Area Look for Nanovna. They have a web site with lots of details. NanoVNA | Very tiny handheld Vector Network Analyzer Many variations out there. Watch for clones. All less than \$100. __________________ Demian Martin Product Design Services
danny_66
diyAudio Member

Join Date: Jun 2005
Location: Lierde
Quote:
 Originally Posted by Hans Polak Can you give me a link to such Alibaba device. I’ll have a look at it and give my comment.
Here are some on banggood for about 50€
__________________
My RefSpeaker v2

Evenharmonics
diyAudio Member

Join Date: Apr 2007
Quote:
 Originally Posted by Hans Polak It amazes me that DIYers on this forum are spending large sums on all sorts of nice project in search of the holy sound grail, but when the option is there to possibly improve sound with very low cost manipulated LS cables, there is no animo. And believe me, blind listening tests are not needed to hear the difference, it is so obvious, at least in my case. Although no satisfactory physical explanations exists and although
Of course cables can make audible difference if they are bad enough.
Quote:
 many people are prejudiced that cables cannot make a difference,
Where are those many people?
Quote:
 wouldn’t it be a challenge to give it a try and leave your comfortzone for once. All you need are 6 resistors, 6 coils and 6 caps plus 2*2.5 meters 4mm^2 zip cord. Hans
Why should they try the cable equalizer when there are real equalizers out there.

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