A little help with my Shocktave build

Started by Pakaloabob, October 23, 2010, 01:13:51 PM

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Pakaloabob

I breadboarded the shocktave, http://www.diystompboxes.com/analogalchemy/sch/shocktave.html and loved the sound.
I decided to commit to perf and used Mitchell's PCB design: http://www.super-freq.com/2010/03/shocktave-pcb/
By the way, what a cool layout with all the transistors in a line.
After testing the perfboard circuit, I don't seem to be getting an octave down like I heard on the breadboard. I used the same components and triple checked my solders with a DMM for continuity. There did not seem to be any solder bridges or cold joints.

Here are my voltages - transistors labeled Q1-Q5, left to right on the schematic:

E/B/C

Q1: 1.610 / 1.972 / 9.35
Q2: 0.998 / 1.599 / 4.28
Q3: -0.6  / 200mv / 9.14
Q4: 0.00 / 130mv / 100mv
Q5: 0.00 / 130mv / 138mv

This is frustrating me because there aren't that many parts. I just debugged my ROG Tri-vibe successfully (solder bridge) and that has so many more components to check.
If anyone could check their own working build and comment on my voltages I would be quite appreciative.  :icon_biggrin:

petemoore

  Check for audio output boosted at output of Q2, Q1 output should be that of emitter follower, unity gain.
  The rest of the circuit doens't ring 'normal bells', but look for signal block with audio probe after Q2/before output...not sure what the voltages would be.
Convention creates following, following creates convention.