7 Dwarfs Wah Cap and Resistor question

[jfrabat]

Hello, guys.  It has been a while since I tried a new pedal (2 years?).  Anyway, I am making myself a 7 Dwarf Auto Wah from a PCB by Delyk ([url+https://www.delykpcb.com/product/7dwarves-auto-wah/]this[/url] board), and I have the following questions:

1. Instructions call for a 7K9 resistor for R26; I cannot locate that exact value in Panama (I moved from Costa Rica to Panama), but I do have 8K2 in my own stock; should I try that one, or will it have a negative effect on the performance of the pedal?

2. Similarly, I cannot find any 8n2 capacitor; I can go 10nf, but, again, not sure what effect that will have on performance. 

What do you guys think?

[Kipper4]

Close enough. try it.
Have fun

[duck_arse]

like kipper sez, try it.

or - 220k parallel with your 8k2 gets you 7k9. close enuff? and -

47nF in series with your 10nF gives 8n24. is that close to what you want?

[jfrabat]

220k parallel with your 8k2 gets you 7k9. close enuff? and -

That is actually what I ended up doing; measured in at 7K75, which is well within the 10% range.  Since I am using 1/8W resistors instead of the required 1/4W, I had enough space.

47nF in series with your 10nF gives 8n24. is that close to what you want?

For the cap, I will just go with the 10nF (I don"t have space for 2 caps).  I hope it does not affect too much the sound...

[ElectricDruid]

The 8n2 cap is C4, right?

In which case, you'll be fine with 10n, and it won't change the sound at all. It looks like it's to limit the high frequency content in the precision rectifier stage. The serious envelope filtering seems to be done by C8 after that, so it shouldn't affect the response.

HTH,
Tom

[jfrabat]

The 8n2 cap is C4, right?

In which case, you'll be fine with 10n, and it won't change the sound at all. It looks like it's to limit the high frequency content in the precision rectifier stage. The serious envelope filtering seems to be done by C8 after that, so it shouldn't affect the response.

HTH,
Tom

Excellent!  Thanks, Tom (and Duck and Kipper)