57.6KOhm Resistor 'Carbon Composite'

[JohnG]

Have a specific purpose for a Carbon Composite 57.6KOhm 0.??? Tolerance Resistor.
The tighter the tolerance the better.
If anybody can point me to a very tight tolerance Brand and Supplier, I'll be quite pleased.
Or just maybe in a gear bag, down in the depths of a no longer required storage vessel, I'm hoping your getting the picture.

[pre65]

Have a specific purpose for a Carbon Composite 57.6KOhm 0.??? Tolerance Resistor.
The tighter the tolerance the better.
If anybody can point me to a very tight tolerance Brand and Supplier, I'll be quite pleased.
Or just maybe in a gear bag, down in the depths of a no longer required storage vessel, I'm hoping your getting the picture.

What wattage ?

[JohnG]

Wattage ? Now that is a good question, I'll have to enquire to get the full value.

[IslandPink]

What is the application ? because carbon composition are not known for having tight tolerances.

[JohnG]

Another question I can't answer, the Kohm specified are needed, a batch bought and tested were not very closely matched.
So I was looking at Texas Components, which I am unfamiliar with as a web site, there are tight tolerances in resistors, but I could not find the value required.

[izzy wizzy]

2 in parallel might get you that odd value.

[Nick]

Yep, if you need that accurate a carbon comp, you need to use a calibrated meter and select one.

[pre65]

Seems that carbon composite resistors can absorb moisture which affects the resistive value.

I read that a slow baking in the oven then covering the body with shellac makes the value more stable. Perhaps clear nail varnish might do ?

[Mike H]

PCB lacquer? Interesting idea.

Why so precise a value?

[IslandPink]

I was going to ask that. Most times I use carbon comps, they are in the signal path as grid-stoppers, I want them to be non-inductive but the values are loose. I suppose you could use them in RIAA but bear in mind they also drift up and down with temperature.

[JohnG]

I,m trusting in the design and build of another, and as I am a EE numpty, I don't know the reasoning behind the critical value.
What I do now know is that the value is best at 1 Watt.

[pre65]

Firstly, what "designer" is going to specify a value that is (in practice) unavailable ? Has he (or she) given any guidance on component selection ?

Secondly, because of the moisture ingress problem very low tolerances are not possible.

And, 82K + 200K in parallel would give 58.15K, thats within 1%, but could be up or down on that value.

[pre65]

Another question.

Has this "design" been built and tested by anyone, or is it "off plan" ?

[JohnG]

I will say I know the build and have been lending a critical ear during the last year during the development.
The build I am now involved with is what I would refer to as a Bespoke Model, produced to suit my taste,hence the additional support with testing Components in Trials, i.e Copper Cap's.

[IslandPink]

I have the feeling it will be unveiled at some point from behind a velvet curtain