The ever popular switching Problem - Loud pop when I engage effect (Mudbunny)

[murdog47]

Might just be the 3pdt. I had a bad one that gave a pop when engaged. I could feel the difference between the bad one and a good one. Give it a push with your finger, see if you feel two clicks instead of the usual single click. I changed out the switch and the pop was gone.

[hubb]

Murdog,

Great tip!  The switch wasn't defective but I had forgotten to solder the bottom left lead. Once that was fixed, the popping was resolved.

I had to offboard the tone pot because of the knobs I wanted to run and I think I torched it. After I replaced the tone pot the pedal seems to work, however the volume is super low, and it seems the volume fluctuates (dips and swells) without any interaction.

I'll search around to see if other posts have tips on the dipping and swelling.  Thanks again!

[hubb]

No luck finding anything.

I thought it might be a good idea to record the voltage at the transistors.  Perhaps someone can comprehend what they mean.

They're all consistent, which is cool. . . . i think

q1
e  2.7 v
b  .466v
c   2.6 mv


q2
e  2.7v 
b  .46v
c  2.8mv

q3
e  2.5v
b  .44v
c   1.1mv

q4
e   2.7v
b  .49v
c  20.3mv


And just to ensure that i'm doing it right, i'm testing these voltages by turning on the pedal, and touching my black lead of my multimeter to the negative lead on the power jack, and the positive lead to each leg of the transistors.

I read somewhere that transistors are linear amplifiers. . . . so if the "e" on my 5088 is the output, are they all working right?

Appreciate the help. . .

-Chris

[hubb]

I think i got it!

I triple-checked for solder bridges and found none.
I checked the values of all of the caps and found they were all correct.
I started checking the resistor values and it turns out I had installed a 100k resistor in R24 instead of the recommended 100R resistor.

In the process of swapping out the resistor i jacked up a bunch of wire connections so I'll be able to fix it and test it out tomorrow.

I don't know anything about how circuits work, but i'll draw a few conclusions just based upon some observations / assumptions.

1) Resistors restrict current and thus reduce voltage (thanks google)
2) R24 is the first resistor from the 9v in (based upon my attempt to understand the schematic)
3) The entire circut was running at a lower voltage than intended, thus the reduced volume
4) I bet my transistor voltages were all low (not sure what they should be)

I'll post again if the fix works.  If someone could confirm/correct  this stuff ^^^ I'd appreciate it.

Thanks!

-Chris

[blearyeyes]

You only have to do that (switch K for R) about ten times before you triple check those pesky letters! And then you'll do it again anyway.. Very common mistake.
Glad you got it fixed.