Resistors between the legs of caps

[frets]

Dear Fellow Friends,
I understand Series lo pass, hi pass; but, will embarrassilngly (sic) admit that when a resistor is between the legs, parallel or “tanked”, how does one determine the frequency effect of the relationship in terms of tone? I’m probably not correctly asking this question, but I have no idea how to calculate the effect of that certain ohm, kilo, Meg + cap on “tone”.
Thanks

[axedoctor]

not totally sure what you're asking, but connecting a resistor and capacitor as described will form an impedance that is the parallel combination of the frequency-independent resistance R and the frequency-dependent reactance 2piFC which is the product of these two factors divided by their sum

if this resistor is placed across the capacitor in a typical treble tone circuit, then it seems to me that the result would be an overall reduction in maximum achievable pickup volume plus a faster high frequency rolloff as the potentiometer value is decreased

[sumgai]

Sept 2, 2019 20:34:59 GMT -5 axedoctor said:

..... connecting a resistor and capacitor as described will form an impedance that is the parallel combination of the frequency-independent resistance R and the frequency-dependent reactance 1 / 2piFC which is the product of these two factors divided by their sum

Fixed the forgotten inversion.  The formulas is spoken as "one over two times pi times frequency times capacitance".  Without that inversion, higher frequencies would have a more difficult time getting through a cap, instead of having an easier time, as we see in the real world.

One question though: Is this question about Tone controls (in the form of a standard treble roll-off), or treble-bleed circuits incorporated with Volume controls?

sumgai

[frets]

Sumgai, No this is not specific to treble bleeds; however, they would be included. Let me use an example. A typical Midrange Push Pull utilizes a resistor/cap combo of 270k/.039uF on 4 with a .001 or .002uF coupled with a 1meg or 1.1 meg resistor. Why these values? Or, more simply, the Rothstein. I’ve seen numerous push pull three way tone controls that have various resistor values in parallel with their capacitor. Again, how does this equate to a particular tone frequency? In other words, how is the combination determined?
Thanks

[Deleted]

XC = 1 / (2 × π × f × C)
XL = 2 × π × f × L

L being a Inductor (Transformer or PICKUP!)

Really need to find you a Electronics book/webpage
i had two books by R.A.Penfold when doing Electronics.. ill try and find the books on Amazon but they keep changing the cover!

1/((1/R)+(1/XC))
reading the title there C in between the legs or R! Para
R+XC 
Would be the Tone Cap BUT!!
Resistor is in 1x10^3 for Kilo and 1x10^6 for Mega
Capacitor is in 1x10^-9 for Nano dont really do Micro and Pico for tone caps


Beginners-Guide-Modern-Electronic-Components
i did think the other book was called Advanced Guide Modern Electronic Components! but i cant find it 
was a dam thick book (twice the size of the first one) and used to be YELLOW


1x10^3 = K
1x10^6 = M
1x10^9 = G
1x10^12 = T

1x10^-3 = m
1x10^-6 = u
1x10^-9 = n
1x10^-12 = p
as capacitors move lower resistors move higher and remember to keep it at one value

[frets]

Thanks to all. Quite a bit out of my league; but, I will continue to research with the answers given. If any of you know of an online calculator that computes a value relative to frequency changes in tone with resistors parallel to caps, would be appreciated. That’s about my level of engineering abilities - zilch. I see various combinations of resistor values in tandem with cap values in the RLC and wonder how the value was selected to reach a tone or rather, frequency result. Stupid simple for me.

[sumgai]

frets,



ange threw at you a lot of beginner's AC theory, so don't feel ashamed that some of it didn't stick the first time around.

I have a couple of web pages bookmarked in my folder, but first, I wanna see if this link does any good for you. It goes to a speradsheet made by our very own JohnH, and he's been improving it for more than 10 years now - it's meant for guitarists specifically, yet it's easy to use, nearly all of the instructions are right on the page(s) you are intersted in.

Try this on for size, and see if it answers your questions. If not, let me/us know, right back here in this thread.

JohnH's Guitar Frequency Response Calculator


Good luck!





sumgai

[frets]

Sumgai,
John’s spreadsheet program is a thing of beauty and does immensely help with my inquiry...all thanks.

[sumgai]

frets,


Don't thank me, I was only the messenger. Thank John for taking the time to develop this idea from not much more than scraps of conversations he particpated in, over the years.

Glad it's working out for you, but again - don't hesitate to ask questions. Either here in this thread, or start another that might be more specific... it's all good!





sumgai