Brains winning over braun . Nice.R.G. wrote: ↑Mon Mar 04, 2024 7:43 pm Equivalent series inductance makes the impedance of a resistor plus ESL higher with frequency. The frequency where the inductive reactance equals the resistance is taken as the critical point of its filtering. The frequency were that happens is F = R / (2 * pi * L). I did a quick look for the self inductance of different types of resistors. Modern film types are passed over as in general under 2 nanoHenries of self inductance. Metal oxide runs to 2-200nH according to the chart I found. Carbon comp, by the way, has almost no self inductance, other than the distributed inductance of the lead wire itself.
If you have a 1K metal oxide resistor with 200nH of self inductance, the frequency where the inductive reactance exceeds the resistance is F = 1000 / (2 * 3.14 * 200nH) = 796 MHz. A 100k resistor hits its turnover at 796GHz.
Of course, the self capacitance enters the picture and prevents the total impedance from ever getting to that turnover. And the self inductance of the wire leads enters the picture. For the wire typically used in guitar amps, the self inductance is about 25nH per inch. That’s a rule of thumb; the exact self inductance is a function of the diameter, but it’s a useful approximation because of that “nH” value. A couple of inches of lead wire plus hookup wire gives a nil-inductance carbon comp resistor as much self inductance as a metal oxide. The bottom line there is that the self inductance of a film resistor is very much in the same rough size as the self inductance of the lead and hookup wires.
The Mega-Hertz and Giga-Hertz in the numbers means that it is highly doubtful that resistor inductance has an effect in audio circuitry.
You are right , running numbers with any familiar values does not yield results within the audio spectrum.
I don’t refuse that sub sonic and hyper sonic frequencies cant modulate the audio spectrum. At the very least they can big an amp down and ruin idealized performance if too much gets inside .
I have brought this up discussing this with you when it comes up in digital sample rate arguments as well, but I don’t have enough experience in that territory to speak about A vs B
this is all just theory for me , like bepone implied I am not a rich a man with time or access to what is necessary to make definite conclusions , and this is the closest I get to believing something might make a difference for a given reasoning, but I have no attachments to being right about this, just assumed plausibility as you say
This is where I don’t understand what’s so logically repugnant, because as already stated “brand” is just synonymous with recipe .
This is the essence of what was going through my head when I read that certain brands of resistors give midrange or percussive effects to amplifiers. Resistors adding a tone color in the audio midrange simply does not make sense. Different materials? Sure. See “Carbon comp”.
An old Allen Bradley doesn’t sound the same as a new modern production carbon composition. They aren’t made using the same exact materials . Mexican coca cola vs USA Coca Cola . Not the same. McDonalds Coca Cola vs canned cola . Not the same .
“Same” composition or not I have never heard two brands of resistors sound identical .