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Projects => IC-based Overdrive => Topic started by: foozertone on November 10, 2007, 05:46:37 PM

Title: IC project part question
Post by: foozertone on November 10, 2007, 05:46:37 PM
I can't find a 26pf cap. I can't even find a 47pf. The smallest cap I can find is 100pf. Am I stupid? Am I missing something?

Thanks

Jeff
Title: Re: IC project part question
Post by: gaussmarkov on November 10, 2007, 06:39:38 PM
I can't find a 26pf cap. I can't even find a 47pf. The smallest cap I can find is 100pf. Am I stupid? Am I missing something?

hi jeff,

ceramic disc and silver mica capacitors are commonly used for these small capacitances.  smallbear carries the silver mica type, but they are generally more expensive than ceramic disc.  you can get ceramic disc capacitors at all of the big suppliers (digikey, mouser, alliedelec, futurlec, ...).

i hope this helps, paul
Title: Re: IC project part question
Post by: foozertone on November 10, 2007, 08:26:34 PM
could the fact that I used a 100pf instead of a 25pf be the root of the project having sound but no distortion? It will be a minute til i can get a 25pf or even anything closer. I'm just playing around with my new breadboard so I'm not too worried about it.

Thanks

Jeff
Title: Re: IC project part question
Post by: gaussmarkov on November 11, 2007, 01:18:53 PM
could the fact that I used a 100pf instead of a 25pf be the root of the project having sound but no distortion? It will be a minute til i can get a 25pf or even anything closer. I'm just playing around with my new breadboard so I'm not too worried about it.

no, you should still be getting approximately the same amount of distortion.  there would be some difference in the very high frequencies, but not (for example) at the fundamental frequencies of open guitar strings.

the the resistors R4 and R5 and pot marked GAIN make the most difference in how much distortion you get.

i hope this helps, paul