If this inductance component of wirewound resistors manifests itself in real circuits, a frequency source can be used to obtain a table of readings as follows:
Column: Frequency/Hz, Voltage/V, Current/mA, Current Phase with respect to input voltage.
Several reading (not less than 5) should be taken.
Using an equivalent circuit for the resistor plus parasitic inductance and parasitic capacitance, the values of both can be calculated, and then tested to predict current and phase values out of the measurement range (extrapolation).
The parasitic inductance is in Series with the resistance and the capacitance in Parallel with the series RL arm.
The derivation of the formulae can be done using BOTH phasor diagrams (2D vectors), and complex numbers.
Since these are measurable qualities of wirewound resistors, the quickest way to ascertain oneself of their behaviour is to measure them and simulate them.
Column: Frequency/Hz, Voltage/V, Current/mA, Current Phase with respect to input voltage.
Several reading (not less than 5) should be taken.
Using an equivalent circuit for the resistor plus parasitic inductance and parasitic capacitance, the values of both can be calculated, and then tested to predict current and phase values out of the measurement range (extrapolation).
The parasitic inductance is in Series with the resistance and the capacitance in Parallel with the series RL arm.
The derivation of the formulae can be done using BOTH phasor diagrams (2D vectors), and complex numbers.
Since these are measurable qualities of wirewound resistors, the quickest way to ascertain oneself of their behaviour is to measure them and simulate them.
It's the regular carbon composition one. I have stocks of 0.47 Ohm. I think it must be good ones that the resistance value is accurate. Must be hard to find such values?
Can be used as a plate load, carrying DC so that it has a chance to enhance even harmonics.
For tube amps, we have many better low noise carbon options than the Allen-Bradley, tho probably expensive.
I agree with AllenB, I believe V coefficient has something to do with the way certain resistor material respond to transient in music.
AllenB talked about its effect on harmonic types when used in crossover. I didn't perceive any change in harmonics type by ears. It may also be undetectable when measured. In amps, V/T coefficients are probably the most important parameters, but not all. I don't even know what the most critical parameter that makes my favorite resistor (secret!
) sounds the way it does.
Yes, it would take a lot of inductance to be significant with higher resistances.
Yes, it would take a new Physics in order for resistors to significantly sound different. Read any resistor shootout thread, it is very scary, like a bunch of liars hang around together.
Dear John. That is quite rude to suggest people that can hear differences between types of resistors in a crossover are liars. Whether it is due to inductance or other factors in the construction of a resistor, the differences are there to be heard quite clearly.
As I have previously said - Anyone who doubts this, is welcome to visit me and I will demononstrate this effect quite easily since my crossover is on an open external board and it takes me seconds to swap out a resistor. Or, if you are too far away from the midlands UK, try it for yourself - compare equal values of say a kiwame 5W carbon film (or a metal oxide resistor) to an ohmite 5W AG series wirewound or mills 5W wirewound - the difference is fairly obvious.
There is also quite a difference in sound between carbon film and metal oxide.
I haven't been to the moon, but I accept people have landed on it.
..you got me 
Wow, what an old thread.
I apparently missed this response back then...
While the theoretical inductance of a straight length of wire can be calculated, it has no use. Current requires a return path. Without a complete path loop, there is no current with which to measure an inductance.
Measurement of a single length of wire for inductance requires you form a loop. And it is that loop that is providing the inductance not the length of wire.
To measure resistors for inductance the first thing you have to do is zero the meter with a short in place of the resistor, the short having the same physical length as the resistor to be tested. The shorted reading can be used to auto-zero the inductance meter, or the value can be written down, and later subtracted from the resistor inductance value.
I've successfully done this all the way down to 250 pico henries, but that level of measure cannot be done accurately in the audio band due to the very low reactance, the lowest I could go was 100 Khz.
jn
Not a double blind test then? Build a double-bind test machine and measure something real we might take you seriouesly, but expectation bias is truly a massive effect and can only be eliminated with double-blind approach.
You obviously don't trust your own ears then?
Would you be able to explain to me the use of the term 'expectation bias' when in reference to just swapping resistors in a crossover, having no idea or expectation of how they will sound? Surely that quip is only potentially relevant for situations such as when somebody is auditioning something new and supposedly better than what they have?
I would like to believe that most people don't get sucked into that scenario ..but that scenario is far from the simple experiment I have been conducting. I had no vested interest in any particular resistors sonic affects one way or the other - I just observed there were differences.
I trust my ears - not what is written about how something should or does sound. Theory doesn't always match practice ..unless complete and flawless
You clearly have no idea about expectation bias, yet its the dominant effect is most listening tests (which is why double-blind testing is essential).
There's quite an illuminating test you can do using a single recording replayed various times through the same equipment - only you explain each time that you've reconnected the amps etc and identify the equipment differently each time. Everyone will make their prejudices very visible as they base their assessment not on what they hear, but on what they expect to hear, despite it being the very same recording every time.
Expectation bias cannot be cured other than by removing the knowledge of what you are listening to. You cannot allow for it, cancel it out or whatever, the brain definitely doesn't play fair.
And no, you cannot trust your own ears. Google "McGurk effect"
You will find what people can actually hear is not the same as what they claim they can hear.
There's quite an illuminating test you can do using a single recording replayed various times through the same equipment - only you explain each time that you've reconnected the amps etc and identify the equipment differently each time. Everyone will make their prejudices very visible as they base their assessment not on what they hear, but on what they expect to hear, despite it being the very same recording every time.
Expectation bias cannot be cured other than by removing the knowledge of what you are listening to. You cannot allow for it, cancel it out or whatever, the brain definitely doesn't play fair.
And no, you cannot trust your own ears. Google "McGurk effect"
You will find what people can actually hear is not the same as what they claim they can hear.
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