Help with scramber clone

Started by ZDHfx, April 20, 2011, 08:14:01 PM

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ZDHfx

I made etched a pcb from tonepad and soldered everything up, checked all the resistors 3 times, checked the solder bridges and cold solders too and it's still not quite right, no clue what could be wrong with it besides the board itself(even though it looks fine, all the traces are clear).  Hers how it works:  blend all the way down, text all the way up = clean tone. blend and text all the way up  mild square wavish fuzz and the octave can sometimes be heard when two notes are played.  It only comes through well if the strings are plucked kinda hard, which I've learned is a sign of the transistors not being biased properly but I dont know how that's possible since it's on a verified pcb and I double and triple checked the resistors.  I'll post trans readings later.  Any clues?

theehman

What transistors did you use?  Maybe you have them turned around?
Ron Neely II
Electro-Harmonix info: http://electroharmonix.vintageusaguitars.com
Home of RonSound effects: http://www.ronsound.com
fx schematics and repairs

ZDHfx

I checked all the transistor pinouts,  I used 2n5306 and a 169b workalike from small bear.

theehman

Did you try audio probing each stage?
Ron Neely II
Electro-Harmonix info: http://electroharmonix.vintageusaguitars.com
Home of RonSound effects: http://www.ronsound.com
fx schematics and repairs

ZDHfx

Quote from: theehman on April 20, 2011, 08:53:38 PM
Did you try audio probing each stage?


no, that's on my list of dbuging to do after I get out of work.  I'm really confused because I'm used to running into improper biasing problem when doing point to point pedals but I was positive that on a verified pcb as long as the components are right nothing can go wrong, if the resistors are right and in the right place, is there anything else that could be giving it that effect?