Does a trainwreck actually need the bruight switch?

[M Fowler]

I read a wire shoot out done in premier guitar a year or so ago and the cheap wire came out as good as the silver or gold high priced crap claimed to be superior.

I don't fall for such nonsense, just pickup the damn guitar and play.

[Structo]

WHAT?!!

No man, you need that $350 power cord to free the electrons floating in space!

[M Fowler]

free electrons floating in space

and the humidity keep my hair curly.

[FunkyE9th]

What is there not to buy? Every cable has an equivalent series resistance (ESR), series inductance (ESL), and a parallel capacitance/resistance that goes to "ground", or whatever your reference is. It acts as an LC lowpass filter with a damped resonance and is proportional to the wire length.

What is the value of the "series inductance" and its origin???

If you really want to find out the origin of the inductance, you can look for an engineering electromagentics book and it will show how they derive it. It has to do with the diameter of the conductors and properties of the dieletric between inner and outer conductor. It's been years since I've seen it, so I just accept the fact that it does exist.

But if you just want the formula to calculate the inductance go here...

http://www.microwaves101.com/encyclopedia/coax.cfm#coax

So yes, the coax has an inductance, whether it's enough to affect a guitar's tone, I've never cared.

Given the coax model given above by Cliff, one can plug in numbers into spice and plot frequency response once you know the R L C. So you should be able to see how it rolls off the highs for a given L

[Cliff Schecht]

What is there not to buy? Every cable has an equivalent series resistance (ESR), series inductance (ESL), and a parallel capacitance/resistance that goes to "ground", or whatever your reference is. It acts as an LC lowpass filter with a damped resonance and is proportional to the wire length.

What is the value of the "series inductance" and its origin???

The inductance is around 500nH per meter or so, depending on the size and composition of the inner conductor. Every piece of wire has a certain amount of inherent inductance and coax cable is no exception. It's not a whole lot when looking at audio frequencies but it will become audible as your cable runs get excessively long.

[Structo]

My point is when dealing with 10-15 feet of guitar cable the inductance and series resistance will not be enough to change anything of concern.
The capacitance on the other hand will have noticeable effect if it is high enough.

Take Mogami W2524 for instance, a commonly used cable.
It has an inductance of 0.2µH/m (0.061µH/Ft).

So you have a 15 ft guitar cord made with W2524,

That is 0.915 uH as in Microhenries.

Negligible at best.

[Zippy]

If you really want to find out the origin of the inductance, you can look for an engineering electromagentics book and it will show how they derive it. It has to do with the diameter of the conductors and properties of the dieletric between inner and outer conductor. It's been years since I've seen it, so I just accept the fact that it does exist.

Dielectric doesn't affect inductance - you'll note that there is no dielectric term in the inductance formula. Inductance isn't effected by dielectric because it is a function of magnetic coupling - hence the distance terms in the derivation.

Capacitance is a much more relevant consideration, inductance is negligible.

[FunkyE9th]

If you really want to find out the origin of the inductance, you can look for an engineering electromagentics book and it will show how they derive it. It has to do with the diameter of the conductors and properties of the dieletric between inner and outer conductor. It's been years since I've seen it, so I just accept the fact that it does exist.

Dielectric doesn't affect inductance - you'll note that there is no dielectric term in the inductance formula. Inductance isn't effected by dielectric because it is a function of magnetic coupling - hence the distance terms in the derivation.

Capacitance is a much more relevant consideration, inductance is negligible.

The formula I was looking at, from the link above has a MUr. Sorry I do not know how to do greek letters.

If I understand the site correctly, MUr is dependent on the dielectric, but it's typically 1 for most dielectric. Plus "D" is dependent on how thick the insulation ( a dielectric) is between the inner and outer conductor. So I considered the thickness of the insulation as a "property" of the dielectric.

[Zippy]

The formula I was looking at, from the link above has a MUr. Sorry I do not know how to do greek letters.

If I understand the site correctly, MUr is dependent on the dielectric, but it's typically 1 for most dielectric. Plus "D" is dependent on how thick the insulation ( a dielectric) is between the inner and outer conductor. So I considered the thickness of the insulation as a "property" of the dielectric.

Setting MUr = 1 is the same as eliminating it from the equation - no effect.

Thickness is not a property, it is a dimension.

[Aurora]

mu denotes magnetic permeability - mu0 is permeability in vacuum ( air) an muR is relative permeability. =1 for air and non ferrous metals increases above 1 for ferrous alloys. Socalled mumetal, often used for magnetic screening or high permeabiltiy cores, can have muR up to several tens of thousands
from this , good cable should not contain ferrous metals

[FunkyE9th]

The formula I was looking at, from the link above has a MUr. Sorry I do not know how to do greek letters.

If I understand the site correctly, MUr is dependent on the dielectric, but it's typically 1 for most dielectric. Plus "D" is dependent on how thick the insulation ( a dielectric) is between the inner and outer conductor. So I considered the thickness of the insulation as a "property" of the dielectric.

Setting MUr = 1 is the same as eliminating it from the equation - no effect.

Thickness is not a property, it is a dimension.

I know MUr=1 has no effect. I can multiply But I am not an expert on dielectrics to know if there are other MUr out there that are applicable, so I did not eliminate it from the equation.

OK, property may not have been the best/right word to describe it, but my point is the thickness of the insulation (dielectric) affects the inductance.

[M Fowler]

What's really funny is after all our talk I haven't seen one reply from the original poster