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DIY Stompboxes => Building your own stompbox => Topic started by: gasmask on May 26, 2014, 02:42:02 AM

Title: Inductorless wah modification
Post by: gasmask on May 26, 2014, 02:42:02 AM
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 (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 (http://www.mediafire.com/view/5j5dx58c1dsoj8j/wah_schematic.jpg)


I will include the soundclips later.  ;)
Gasmask
Title: Re: Inductorless wah modification
Post by: gasmask on May 26, 2014, 06:55:00 AM
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
Title: Re: Inductorless wah modification
Post by: Blitz Krieg on May 27, 2014, 04:14:27 AM
sounds good
Title: Re: Inductorless wah modification
Post by: joegagan on May 27, 2014, 12:57:03 PM
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.
Title: Re: Inductorless wah modification
Post by: joegagan on May 27, 2014, 01:20:31 PM
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.

(http://juansolo.demon.co.uk/stompage/schematics/Torchy%27s%20Veros/Circuit_Snippets/Tim%20E%20Idiot%20Wah/idiotwah_sch.gif)

(http://img.photobucket.com/albums/v311/joegagan/schems/LeftyIdiotWah_zps39e28dcf.gif)

(http://img.photobucket.com/albums/v311/joegagan/schems/WahFreeper_zps703d0d34.gif)
Title: Re: Inductorless wah modification
Post by: allesz on May 28, 2014, 03:43:43 AM
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.
Title: Re: Inductorless wah modification
Post by: joegagan on May 28, 2014, 05:12:19 PM
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
Title: Re: Inductorless wah modification
Post by: mac on May 28, 2014, 06:58:03 PM
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
Title: Re: Inductorless wah modification
Post by: karul on May 28, 2014, 07:34:13 PM
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



Title: Re: Inductorless wah modification
Post by: joegagan on May 28, 2014, 10:29:23 PM
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)

(https://scontent-a-lax.xx.fbcdn.net/hphotos-xpa1/t1.0-9/1622256_654286704631411_560724971_n.jpg)
(https://scontent-a-lax.xx.fbcdn.net/hphotos-xfa1/t1.0-9/1782136_654286961298052_1195494869_n.jpg)