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Topics - ThatGuyThere

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Tech Help - Projects Page / Flabulanche Noise problem
« on: July 26, 2019, 01:41:27 PM »
I am having a problem with my Flabulanche pedal that recently put together.  It is generating a consistent wooshing sound that is quite annoying.  It not abundantly evident when the volume and gain are down, but it is there. 


I also, am not seeing any change in the Q3 values if I change the switch for the compressor. 
Here is some data:
Before D2:  9.16v
After D2:  8.94v
Test Point 1:  11volts
Test Point 2:  Bouncing around ALOT 1 to 11.24 volts
Test Point 3:  13

D  11
S  0.552
G  0  (lots of buzz when testing)

D  11.26
S  0.629
G  0

Q3  Comp. Switch left        Q3  Comp. Center           Q3  Comp. switch right
D  13.04                           D  13.11                        D  13.04
S  0.296                           S  0.29                          S  0.296
G  0.011                          G  0                               G  0.012

D1  switch left                    D1  center                    D1  switch right
3.18                                   0.17                            3.25

D  10.71
S  3.63
G  1.50

I am not sure why the compressor circuit does not seem to be doing much to effect the Q3.  Any ideas?  Also, the annoying noise which seems to grow somewhat more complex as it is on longer.  Is that an oscillating sound?  Could this be the LT1054 chip?  Transistor?  Filter capacitor?
Thanks for your help,

Tech Help - Projects Page / Flabulanche power section
« on: July 02, 2019, 07:18:15 AM »
I am finally building the Flabulanche pcb that I had sitting around.  I am having problems with the voltages not getting to the LT1054, and consequently, nothing else is happening on the board.  As you can see from the schematic, I have about 9 volts after D2.  I am getting 8.99 v on the + side of the 100 uF (c13).  On the 15v Zener (D3) I get about 1.87 v to 2v.  It fluctuates a little.  After D3, I get almost nothing  on C14 has 0.02 volts.  It almost seems like there is an issue in the trace between the C14 and D3 and then again between D3 and Pin 8 of the IC. Or is the IC messed up?  Would there be a way to jumper between C14 and Pin 8?  Would that be bad?  Previously, I did not put the Zener in D3 because people said that it was optional.  I was still getting these issues.  Consequently, I ordered a lot of Zeners only to find out that it did not really change the problem.
The IC measures as follows:
Pin1:  0.031v
Pin2:  0.003v to 0
Pin3:  0
Pin4:  0.074
Pin5:  0
Pin6:  starts at 1.3v and bounces down to about 0.06v
Pin7:  0.018v
Pin8:  -0.004v
None of these voltages are making any sense to me.  D4 and D5 have nothing going on.  Except, that D3 has a voltage that sort of fluctuates around 1.8 to 2 volts.  I have gone through and reflowed the pads for all of the spots described above and am not getting any significant changes.  What else should I do?  Thank you for your help.

Tech Help - Projects Page / Serendipity v4 No effect on signal in circuit
« on: January 08, 2019, 08:21:06 AM »
Hi there,
I am finally getting around to building a Serendipity v4 that had been sitting around.  I am having some issues where the pedal was passing the signal through the circuit and having no effect on the sound.  I get no effect from the pots and no drive.  I know that the signal is somewhat attenuated by the sound coming out.  I do have a true bypass when it is switched off.  I have used an audio probe and am getting a signal throughout the circuit, but again, it is basically just a somewhat scratchy quieter version of the bypass signal.  Also, I am not getting the LED to light up, but that may or may not be an issue of a broken LED (I do not have a replacement at the moment).  I am wondering if the main issue would more likely be a grounding issue or an off board wiring issue.  Thanks for your help. 

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