SOLVED Special Overdrive (farting distortion)

[diafebus]

Hello, i finished my built yesterday, and i tried without the box, just to see how it sounds before i do the casing, but for some reason the pedal juat sounds like (fart distortion, when you play softly it sounds clean, and suddenly when you push a little harder it jumps into a fuzzy like distortion.

What could be wrong with it? Im not seeing anything.. maybe one of the transistors? If needed i'll upload a soundfile.

Thanks

PS: audio file, i think it can be more explanatory of the possible problems

Voice 005

Listen to Voice 005 by Adrià E. S. #np on #SoundCloud

on.soundcloud.com

 

[music6000]

Hello, i finished my built yesterday, and i tried without the box, just to see how it sounds before i do the casing, but for some reason the pedal juat sounds like (fart distortion, when you play softly it sounds clean, and suddenly when you push a little harder it jumps into a fuzzy like distortion.

What could be wrong with it? Im not seeing anything.. maybe one of the transistors? If needed i'll upload a soundfile.

Thanks

PS: audio file, i think it can be more explanatory of the possible problems

Voice 005

Listen to Voice 005 by Adrià E. S. #np on #SoundCloud

on.soundcloud.com

Confirm that C1 is100pF, not 100nf or 1nF???

 

[harmaes]

I also finished this circuit recently and the farty decay is indeed well known and much discussed even among buyers of the real thing.

I’ve moved from an OPA2134 to an NE5532AP which I like better in this pedal and removed the jazz/rock switch and the 470n because the jazz setting is useless.
Make sure you’re not on the jazz setting because that sounds like sh*t IMO.

Also consider adding an on-off-on switch for clipping diodes between pin 1 and 2 of the first gain stage (C5 I guess, the 82pf) and have 2x 3mm red leds on one side, normal (open) in the middle and some other combination on the other side. I used asymm 1n4148 (1 Vs 2 anti parallel) but don’t really like them and found nothing else that sounded right.
The red leds make it sound less farty and a little warmer.
If you have your elco caps rated above 18v then use 18v which improves the sound of the pedal.
Also keeping the accent low will have the least amount of fartyness.

Give it a try and let us know what you come up with and what you like best!

 

[KR Sound]

What about D1? Would that make a diff with it missing?

 

[harmaes]

I tried removing the D1 3mm led that’s the clipping diode for the second gain but it didn’t make it better so I kept it to have the sound the base pedal was “designed” for.

 

[Laundryroom David]

Hello, i finished my built yesterday, and i tried without the box, just to see how it sounds before i do the casing, but for some reason the pedal juat sounds like (fart distortion, when you play softly it sounds clean, and suddenly when you push a little harder it jumps into a fuzzy like distortion.

What could be wrong with it? Im not seeing anything.. maybe one of the transistors? If needed i'll upload a soundfile.

Thanks

PS: audio file, i think it can be more explanatory of the possible problems

Voice 005

Listen to Voice 005 by Adrià E. S. #np on #SoundCloud

on.soundcloud.com

When a build isn't working, it's really helpful to do a close visual inspection first - check to make sure you have completely populated your board and make sure that you've used the correct values for each component. Check for cold solder joints, bridged joints, etc...

 

[diafebus]

Guys first of all, thank you very much for all the help! Pretty much appreciated!! Looks like i missed the diode, D1, but yes the main problem was the 100pF C1 which i accidentally installed a 100nF thats why it farted so much, it sounded kinda nice without D1 i will install it now and see the difference, i'll study the mods to see if i do some mods or I leave it stock! For now i think beeing a little fat its okay for the pedal's goal. Most Dumble style pedals tend to sound fat, they are not the kind of pedals to do riffs, more like single line notes.

 

[Feral Feline]

Some people have intentionally paid good money to get a pedal that farts...

Glad you sorted it out — mark it "solved", @diafebus