Can i use the nearest capacitor like I use the nearest resistor?

Started by Hav, September 05, 2014, 04:35:17 PM

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Hav

Hi all

am building a few pedals and dont have 0.01uf/10nf caps... can I just use the nearest to get a similar sound?? how far should I go up or down from this value?

Thanks :-)

Govmnt_Lacky

With caps, I usually do not wander more than +/- 20% So, unless you can get a 12nF cap then you might either have to buy a 10nF -OR- risk the chance of some audible changes.

Resistors is only 10%
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KazooMan

You can always use caps in series or parallel to get to required capacitance and voltage values in a pinch.  

I should have added that you will find that there are common values for capacitors and resistors that are used over and over again.  It makes good sense to buy these in bulk to get the price savings (often huge).  For example, at Smallbear metal film resistors are $0.20 each.  A bag of 100 is $3.95. 

Buy in bulk for common values!

Hav

yep thats as i thought tbh. I ordered bulk from JPR Electronics here in the UK and they got everything in the box EXCEPT my 10nf's  :-(

Good info about the caps in series/parallel and I think il just have to wait it out until I buy another large order (min £30 at most places here)..

GibsonGM

In case you don't know, Hav.  Sorry if you DO know:

Caps in parallel add.   Just Cap 1 + Cap 2...

Caps in series follow the product over sum rule:    Cap1 * Cap2  /    Cap1 + Cap2
The result will always be less than the biggest cap's value.

For more than two in series, you probably don't want to get into it!!   ;)     

Total opposite of resistors, keep in mind!!
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ashcat_lt

This completely depends on where the cap is and what it's doing.  Some places it won't make hardly any difference as long as maybe you're in the same decade.  Other places, maybe a bit more.  Some filters you might be able to make up the difference by adjusting the associated resistor.  You can always try adding caps in series/parallel like mentioned above, and also as mentioned the tolerance for most caps isn't particularly tight to begin with, so...

petemoore

  Depending...
  Say if it's a cap to ground for treble rolloff, use a bigger value cap and add in a V/Resistor [pot] to find the value [for a smaller, fixed resistor to handle on board] or add the pot as a titled knob [treble].
Convention creates following, following creates convention.

armdnrdy

Quote from: ashcat_lt on September 05, 2014, 09:48:25 PM
This completely depends on where the cap is and what it's doing. 

#1

In a LFO a different cap will change the rate. Decoupling cap or supply filter cap....not so much.
I just designed a new fuzz circuit! It almost sounds a little different than the last fifty fuzz circuits I designed! ;)

duck_arse

Quote from: GibsonGM on September 05, 2014, 07:54:32 PM
Caps in series follow the product over sum rule:    Cap1 * Cap2  /    Cap1 + Cap2
The result will always be less than the biggest cap's value.

For more than two in series, you probably don't want to get into it!!   ;)     

the result will be less than the smallest cap's value.

more than 2 caps is as easy: 1/{(1/C1)+(1/C2)+(1/C3)+(1/...Cn)}

hav - what is the nearest value you have? if it's a part of an R/C, you can adjust the resistor value.
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ashcat_lt

Quote from: duck_arse on September 06, 2014, 10:41:46 AMthe result will be less than the smallest cap's value.
To be fair, he wasn't technically wrong.  It will also be less than the biggest.  ;)
Quotemore than 2 caps is as easy: 1/{(1/C1)+(1/C2)+(1/C3)+(1/...Cn)}
You can also just use the formula for two components iteratively, which is sometimes easier to do in your head.