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I'm trying to build a guitar distortion pedal.

Alright, a bit about the motivation behind this project : It's my friend's birthday in a couple of days and I wanted to get him a distortion pedal cause he's been saying he'd like one for some time. I soon realized that would cost me an arm. So I figured i`d build one.

I've been getting into electronics for a while now so i've gathered quite some components but not that many big through hole capacitors, in fact I almost only have smd capacitors and I was wondering...Could I use SMD capacitors to do my biding in this project? I've never quite understood the reasons why you'de choose one type or physical size of capacitor over another when they are both rated the same capacitance and voltage ratings...I hope you can enlighten me!

Here`s the schematic and a link to the instructables' project page.

N.B. I have all I need to etch my board and given the time constraint that's another good reason i'd want to use smd as I can just reflow my board...

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Just to make sure, because I do realize there are different types of SMD caps. I mean ceramic ones. These kinds :

enter image description here

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  • \$\begingroup\$ As long as they're the same value and type, using SMD should not be an issue at all. \$\endgroup\$ – RJR Apr 30 '14 at 5:25
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    \$\begingroup\$ You do realize that making a pedal work in two days is not that easy, do you? Just saying you might want to prepare a "minor gift" for your friend. good luck! \$\endgroup\$ – Vladimir Cravero Apr 30 '14 at 5:42
  • \$\begingroup\$ 5 days. lol and we do have a back up! haha. \$\endgroup\$ – Ethienne Apr 30 '14 at 5:53
  • \$\begingroup\$ Apart from the obvious things like capacitance, voltage and possible polarity, there's also temperature coefficients, component value accuracy, ESR and so on. Wikipedia. \$\endgroup\$ – Lundin Apr 30 '14 at 7:03
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As @Lundin mentioned, there are other parameters in play. Another is the actual impedance vs. frequency curve. Though for the audio range, there shouldn't be much difference. All of this information should be in the datasheets. I suggest looking up the datasheet for the caps you have as well as the ones from the instructable to make sure there are no big differences.

Another thing to consider is that guitar pedals are objective. Unlike many other questions on this site, you are trying to add distortion, not remove it. Further, you are trying to add just enough distortion to the signal to make it sound "good". That being said, using different components may make it sound better or worse. It's all up to your friend. With SMD capacitors, the leads are much smaller, leading to less parasitic capacitance. Using these components may also shrink the PCB area and mutual inductance. I would imagine it would sound different, but I can't say how much.

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  • \$\begingroup\$ Alright, thanks. I'll try it and let you know what the result was! \$\endgroup\$ – Ethienne May 1 '14 at 5:31

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