news flash, guys...

[jneutron]

In a discusion at cables, this was overheard...

""Given that the lumped parameters are the relevant ones for speaker cable use, one would simply calculate what the bandwidth of the lumped parameters is, and then derive the effective risetime.""

And my response:

Wait a minute, did you just say that the lumped parameters are the relevant ones? Hearing you say this is rather novel..

On a lighter note...I lament the inability to actually post pictures over at asylum land, whereas here it's a no brainer..but it appears that linking to pics over here does not work...or is it just me?

I just hate the pictures moving away with time..perhaps, this can be resolved in the future..

Cheers, John

 

[mtrycrafts]

In a discusion at cables, this was overheard...


And my response:


On a lighter note...I lament the inability to actually post pictures over at asylum land, whereas here it's a no brainer..but it appears that linking to pics over here does not work...or is it just me?

I just hate the pictures moving away with time..perhaps, this can be resolved in the future..

Cheers, John

Yes, I just saw this there glad you posted here for responses.

Yes, it is a newsflash but probably expected from JR. When it suits him lumped parameters are important, like in this case, and when it doesn't suit his needs, there are yet to be discovered parameters at work. Go figure. You cannot or you will be a real inmate at the AA

I am not sure about the pictures here though, very few are visible to me

 

[jneutron]

Yes, I just saw this there glad you posted here for responses.

Yes, it is a newsflash but probably expected from JR. When it suits him lumped parameters are important, like in this case, and when it doesn't suit his needs, there are yet to be discovered parameters at work. Go figure. You cannot or you will be a real inmate at the AA

I am not sure about the pictures here though, very few are visible to me

Here's the stuff:

First pic shows the tradeoff of L and C for a specific insulation type.

Second is the effective DC calculation for gene's recent wire article..

Third is the prop velocity of any transmission line vs the effective DC.

Fourth is an overlay of a coaxial cable designed with many different insulation thicknesses. All with a DC of 2.7, tefzel in this case.

As can be seen, they all overlay one another. This was a suprise to me, I had expected many different curves, but got only one.

That is when I massaged the equations, to find the L*C=1034*DC thing..


Cheers, John

 

[gene]

On a lighter note...I lament the inability to actually post pictures over at asylum land, whereas here it's a no brainer..but it appears that linking to pics over here does not work...or is it just me?

I just hate the pictures moving away with time..perhaps, this can be resolved in the future..

John;

We just did another upgrade to our servers (hopefully final for along time) where we are now hosting the forums on their own server. This may have messed up your pics and not sure we can fix it. I promise it won't happen again! Sorry

 

[jneutron]

John;

We just did another upgrade to our servers (hopefully final for along time) where we are now hosting the forums on their own server. This may have messed up your pics and not sure we can fix it. I promise it won't happen again! Sorry

No problem.

What I was talking about, is that old posts over at AA props which linked to stuff here, no longer connect, they leave that x in the box thingy.

I wasn't sure if your server just ignored the link requests, or if it was intentionally broken, so that discussions at another forum could not use your server for picture storage.

It is, of course, not for me to decide..

I would, however, enjoy a place to post some good information about the stuff I've done, so that I could link to them for discussions. Pics and stuff, kinda like a tech info page for designing, in this case, cables to get specific desired parameters. Linking to it wouold kinda be like usin ya...but on the other hand, the full info with explanation would be on your site...

Cheers, John

 

[Richard Black]

Here's the stuff:

....Fourth is an overlay of a coaxial cable designed with many different insulation thicknesses. All with a DC of 2.7, tefzel in this case.

As can be seen, they all overlay one another. This was a suprise to me, I had expected many different curves, but got only one.

You should certainly get different curves for different insulation thicknesses - insulation (for a given inner core size) gives lower capacitance and higher inductance and hence higher impedance, for a given dielectric (and hence propagation velocity).

Are you sure you typed the equations in correctly?

Richard

 

[jneutron]

You should certainly get different curves for different insulation thicknesses - insulation (for a given inner core size) gives lower capacitance and higher inductance and hence higher impedance, for a given dielectric (and hence propagation velocity).

Are you sure you typed the equations in correctly?

Richard

Farily confident that I did. I was very suprised by the relationships. ..I'm kinda busy here at the moment, but at lunch, I'll post all the equations and derivations, it's not very fast with the HTML code. That way, everyone else can look for errors on my part..

The prop speed is directly related to the mu and epsilon of the dielectric. Since we are talking about mu =1 here, the prop speed is only related to the epsilon of the insulation for coaxial structures.

Cheers, John

 

[Audioholics]

old posts over at AA props which linked to stuff here, no longer connect, they leave that x in the box thingy.

I wasn't sure if your server just ignored the link requests, or if it was intentionally broken, so that discussions at another forum could not use your server for picture storage.

We didn't do anythiing intentional to break stuff, but the forums are now forums.audioholics.com/forums, instead of www.audioholics.com/forums... which might account for the errors.

What's weird though, is that the old links should still work as we have forwarding enabled that makes www.audioholics.com/forums/ (need the end slash) a valid URL.

Oh well...

 

[jneutron]

Farily confident that I did. I was very suprised by the relationships. ..I'm kinda busy here at the moment, but at lunch, I'll post all the equations and derivations, it's not very fast with the HTML code. That way, everyone else can look for errors on my part..

The prop speed is directly related to the mu and epsilon of the dielectric. Since we are talking about mu =1 here, the prop speed is only related to the epsilon of the insulation for coaxial structures.

Cheers, John

Ok..the eq's. D.C. is epsilon, the dielectric coefficient..

First, the capacitance of a coaxial line..

C = ^{(2 * pi * D.C.)}/_{Ln(^R_o/_{R_i})}

Next, the inductance of a coaxial line..

L = (^mu/_2*pi) * Ln(^R_o/_{R_i})

Re-arrange both equations, with Ln(^R_o/_{R_i}) on one side:

Capacitance:

Ln(^R_o/_{R_i}) = ^{(2 * pi * D.C.)}/_C

Inductance: set mu =1, as the dielectric is non magnetic:

Ln(^R_o/_{R_i}) = (L * 2*pi)

Note: both equations equal the Ln ratio, so equate them..

^{(2 * pi * D.C.)}/_C = (L * 2*pi)

The 2 * pi's cancel:

^(D.C.)/_C = L

Bring C to the right:

D.C. = LC

This means that for a specific insulation type, the product of L and C will be a constant. Note that no where within that result, is the specific radii of the inner conductor, or the outer braid radii..they were cancelled out at the beginning of the analysis.

Weird, ain't it??

Note that up to now, I have been using L * C = D.C. *1034. It is interesting, in that I have been using nHenries for inductance, and pf for capacitance...If I used pH for inductance, this would have been L * C = 1.034 * D.C.

I believe, though have not tried yet, to find out if that 3.4% error is a result of truncation or rounding from the data I used for my initial analysis. (ya always gotta check your sources, guys...lots of garbage out there on the web that is just totally inaccurate..

OH, also...

Impedance Z = sqr(^L/_C)

And

V _{(fraction of lightspeed)} = ¹/_sqr(LC)

also stated as:

V _{(fraction of lightspeed)} = ¹/_sqr(D.C.)

What is significant, and the entity that Jr didn't understand, is that when a cable is measured, giving an L and C, the product of those gives the EFFECTIVE DC, which provides the boundary line for that construction geometry, and the velocity of propagation...

With the LC graph of D.C. and the one of velocity, any cable measured can be quantified as to the utilization of the geometry.. In other words, how close it comes to coaxial cable when it comes to containing the magnetic and electric fields..

Everybody: Please check my math....I've been wrong before, (just ask my ex)

Oh well...back to the winding machine...

Cheers, John..

Oh man, writing eq's with html is a PITA...hope I didn't have any typo's..

 

[gene]

I would, however, enjoy a place to post some good information about the stuff I've done, so that I could link to them for discussions. Pics and stuff, kinda like a tech info page for designing, in this case, cables to get specific desired parameters. Linking to it wouold kinda be like usin ya...but on the other hand, the full info with explanation would be on your site...

Ah I see John. I pay the bill for more bandwidth, so you can have a field day on these forums and link it to other places How about donating an article or two to us from time to time

 

[jneutron]

Ah I see John. I pay the bill for more bandwidth, so you can have a field day on these forums and link it to other places How about donating an article or two to us from time to time

Done.

Actually, I was thinking about making this whole t line derivation stuff an article for ya...

Hey, I know ya gotsta pay the bills....

Cheers, John