Hi boys,
I would like to know how much inductance and capacitance metal film resistors generate when used in audio amps circuits. How much percentage value would be that?
Thanks in advance 👍
I would like to know how much inductance and capacitance metal film resistors generate when used in audio amps circuits. How much percentage value would be that?
Thanks in advance 👍
InductNce and capacitance aren't ratios, and your question is far to general to have a single answer.
Select a value look up the actual part number and refer to the manufacturers specification sheet for your answer.
Different values have different annomolies, just like all other componets in use.
I personally don't care about this, main thing about metalfilm is less noise compared to carbon types.
Willem.
Willem.
If it's a percent, it's then it's in the 1000th percentile or higher more than likely.
For audio, the inductance and capacitance is small enough to omit from the picture.
FWIW, I use MF types for grid leak on signal tubes, and MO (metal oxide) type for the grid stopper. On power tubes, I use MO for both. On my phono stage, I did use CC (carbon comp) for the grid leak though - because I had them and they look cool.
For audio, the inductance and capacitance is small enough to omit from the picture.
FWIW, I use MF types for grid leak on signal tubes, and MO (metal oxide) type for the grid stopper. On power tubes, I use MO for both. On my phono stage, I did use CC (carbon comp) for the grid leak though - because I had them and they look cool.
You are asking a question with too little context...like asking how long is a piece of string?
Any given circuit will require resistors to have certain attributes for best performance...you need to look at it's designated use to figure out the answer to your question. There is no "best' resistor, there are only resistors that will work best in a particular circuit.
Mike
Any given circuit will require resistors to have certain attributes for best performance...you need to look at it's designated use to figure out the answer to your question. There is no "best' resistor, there are only resistors that will work best in a particular circuit.
Mike
Metal film resistors are usually made non-inductive, so the inductance is about the same as a piece of wire
of the same length, around 10-20nH for smaller resistors.
The capacitance could be determined by cutting the film element somewhere to open circuit it, and then measuring
the capacitance between the ends. It will be on the order of a few pF, and is a function of size rather than value.
of the same length, around 10-20nH for smaller resistors.
The capacitance could be determined by cutting the film element somewhere to open circuit it, and then measuring
the capacitance between the ends. It will be on the order of a few pF, and is a function of size rather than value.
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One doesn't care that much of inductance and capacitance between two lambda metal resistors for analog gears. It beginns to be a concern for HF, digital gears. And if a very low inductance is needed you have Ayrton Perry style winding resistors.
But for RF you also need to focus also about inductance and capacitance of what is before and after the resistor...the layout of the traces on which it is soldered for the question becomes a concern imo and if we still talk audio.
But for RF you also need to focus also about inductance and capacitance of what is before and after the resistor...the layout of the traces on which it is soldered for the question becomes a concern imo and if we still talk audio.
Used as grid/screen stopper the inductance of the circular resitance media might be enough to
create an oscillator , at least for high Gm tubes. In this position CC is preferred .
create an oscillator , at least for high Gm tubes. In this position CC is preferred .
The late @DF96 and @GoatGuy would disagree.
https://www.diyaudio.com/community/threads/tube-amps-and-resistor-composition.343652/post-5938153
I have looked some Vishay datasheet at Mouser and failed to see Inductance or Capacitance values mentioned. Do I have to look for some other name as Distortion or DHT etc ?
What is the general opinion about Carbon Resistors for an SET audio tube amp?
There´s your answer, for all practical means they are irrelevant.
Carbon comp or carbon film? Carbon comp are ancient, noisy, and drift over time. Carbon film are more expensive than metal film and don’t offer any advantages at audio frequencies. Can’t go wrong with metal film.
Old Philips 0,5W metallfilms (1980 ? with metalcaps on both ends) aŕe about 0,2pf. Inductance depended on the needed trimming (carving of a spiral to remove basematerial) to get a certain resistance value. Some values had no "spiral" at all, others up to a few turns, Inductance would be in the same range as the inductance of a similar, either straigth or spiraled wire, at audio frquencies nothing to worry about.