Inductorless wah modification

Started by gasmask, May 26, 2014, 02:42:02 AM

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gasmask

I've recently bought a breadboard ( finally ). I always wanted to have wahwah pedal but it's too expensive to buy original ones. I breadboarded inductorless wah by beavis audio (http://www.beavisaudio.com/Projects/ColorsoundWah/index.htm).
It sounds good but I wasn't satisfied. My mods:

1. To increase the level of pedal I changed 330Kohm resistor to 100K. I removed 47kohm, 100Kohm and 2.2nF in main signal path. It just changed into a simple booster.

2. Some people on this forum said that it will be better to make both capacitors in bottom T part equal. So I made both 2.2nF.

3. According to some other schematics, I have changed 33Kohm resistor before wah pot to 360ohm.

4. Changed 15nF to 6.8nF. Sounds better. In next week I will try with other values from 2.2nF to 27nF.


Now my schematic:
http://www.mediafire.com/view/5j5dx58c1dsoj8j/wah_schematic.jpg


I will include the soundclips later.  ;)
Gasmask

gasmask

Soundclip (I haven't got enclosure for this pedal so I change position of wahpot with my hand) : http://www.mediafire.com/listen/lvffhdl1m9duhzv/inductorless_wah.mp3

Blitz Krieg


joegagan

i like the sound of it!
i was also advised to keep the two caps equal value. perhaps from a pure mathematical perspective this is true, but my ears told me that i liked a mismatch there.
my life is a tribute to the the great men and women who held this country together when the world was in trouble. my debt cannot be repaid, but i will do my best.

joegagan

here are 3, two are mine and the idiot wah that i based lefty idiot wah on. the freeper seemed to work better in front of fuzz as i recall. note the mismatch caps on the T on the lefty.





my life is a tribute to the the great men and women who held this country together when the world was in trouble. my debt cannot be repaid, but i will do my best.

allesz

Hallo, I jump in with some questions about this circuits:
I always had luck with the idiot wah, adapted a little of course, my preference is for matched caps in the t network btw;
I don't hear much difference adding a second t network like in the colorsound.... maybe it's just that I did not try it at high volume?

I will give a go to the freeper.

joegagan

hi allesz, let us know how it goes! yes, i posted all 3 to give ideas about different ways to go.

i did pot replace on a colorsound reissue ( 90s, inductorless)  - sounded awesome!
******* youtube embed not working***

https://www.youtube.com/watch?v=REpvoPhZTGg
my life is a tribute to the the great men and women who held this country together when the world was in trouble. my debt cannot be repaid, but i will do my best.

mac

#7
I posted a LTSpice simulation in the Spice board.

http://www.diystompboxes.com/smfforum/index.php?topic=99448.0

I'd change the 15n cap (in series with the 33k) to 22n - 33n to make the curves of the same height... that if you don't want a bump near the lows.
Useful range is about 33k - 47k or less, so rotating a 100k linear pot 90 degrees should work.

R8 is not 33k but 470 ohm.

If you make both caps equal try 4n7, 3n3. 2n2 might sound too trebly.

mac
mac@mac-pc:~$ sudo apt install ECC83 EL84

karul

#8
Quote from: joegagan on May 28, 2014, 05:12:19 PM******* youtube embed not working***

it is working -
but for some reason only with HTTP (Hypertext Transfer Protocol) but not HTTPS (Hypertext Transfer Protocol Secure)

when you are copying link from youtube the addres is https://www.youtube.com/watch?v=....  - just change it to http://www.youtube.com/watch?v=.... and you're done




joegagan

thanks for that - i tried goofing wiht it, i am glad you figured it out. thanks for posting. now for some gratuitous wah pot porn. ( same wah as the one in video)


my life is a tribute to the the great men and women who held this country together when the world was in trouble. my debt cannot be repaid, but i will do my best.