madbeanpedals::forum

Projects => Tech Help - Projects Page => Topic started by: okeephoss on July 23, 2016, 06:40:57 AM

Title: Deathklaw feedback not going to infinity?
Post by: okeephoss on July 23, 2016, 06:40:57 AM
Am I missing something.  I used BC 549 instead of the BC550's.. the pinouts are same based on my googling.
Title: Re: Deathklaw feedback not going to infinity?
Post by: madbean on July 23, 2016, 10:10:24 AM
Using BC549 should be okay but doesn't affect the feedback. Do you get oscillation if you turn the control all the way up? If not, you might need to lower R24 to 12k.
Title: Re: Deathklaw feedback not going to infinity?
Post by: okeephoss on July 24, 2016, 01:52:31 AM
i guess theres a slight oscillation... replaced the resistor... still most repeats i can get is about 6-7?? 
Title: Re: Deathklaw feedback not going to infinity?
Post by: okeephoss on July 24, 2016, 08:43:27 PM
I replaced the pot, reflowed all joints.  Maybe a bad IC?... though the ghost switch is working so i assume they're both good?  Lost over here.  I'll stick w my MXR for now. 
Title: Re: Deathklaw feedback not going to infinity?
Post by: madbean on July 24, 2016, 10:47:26 PM
From your earlier post - do the repeats die out completely after 6 or 7? If so, you actually may have a wrong resistor value somewhere in the build, esp. around the PT2399. A clear pic of the top of your PCB would help determine that.
Title: Re: Deathklaw feedback not going to infinity?
Post by: okeephoss on July 24, 2016, 11:19:17 PM
yes they die out completely... I socketed R24 and tried some different values there. no change.  thanks for the reply MB
Title: Re: Deathklaw feedback not going to infinity?
Post by: okeephoss on July 29, 2016, 05:04:19 AM
finally got around to looking this over and found out that they sent me a bunch of 20K resistors instead of the 10K's...
right?  red, black, black, red, brown, is 20K... SMH...
Title: Re: Deathklaw feedback not going to infinity?
Post by: okeephoss on July 29, 2016, 05:06:00 AM
has this happened to anybody??? surprised it was from Smallbear, they seem to always send the right thing... guess I'll be checking all values before installing in the future.