Help with Guitar Distortion Pedal Schematic

  • Thread starter Thread starter MG-Zero
  • Start date Start date
  • Tags Tags
    Schematic
Click For Summary
SUMMARY

This discussion focuses on troubleshooting a guitar distortion pedal schematic, specifically addressing concerns about a potential short circuit involving a 220uF capacitor and diodes. The user confirmed that the audio amplifier is functioning correctly, but questioned whether the current bypasses the capacitor due to the circuit configuration. Clarifications were provided regarding the necessity of including diodes in the circuit to achieve proper clipping, with an expected output of approximately 4 volts peak-to-peak at a gain of 20 from the LM386 op-amp.

PREREQUISITES
  • Understanding of guitar pedal circuitry
  • Familiarity with LM386 op-amp specifications
  • Knowledge of capacitor functions in audio circuits
  • Basic electronics concepts, including series and parallel configurations
NEXT STEPS
  • Research LM386 op-amp gain configurations
  • Learn about diode clipping in audio applications
  • Explore capacitor roles in signal processing
  • Study common guitar pedal circuit designs and troubleshooting techniques
USEFUL FOR

Guitarists, audio engineers, and electronics hobbyists interested in building or troubleshooting guitar distortion pedals will benefit from this discussion.

MG-Zero
Messages
3
Reaction score
0
Hey, I've been working on putting this schematic together (Not my design, got it off of instructibles.)

The-schematic.jpg


It's a distortion pedal for a guitar, at this point I have an amplified clean sound coming through, so I know the audio amp is working. My question is, since there's a short circuit following the 220uF capacitor, won't all of the current just bypass that section with the diodes? If so, would it be better to put that part in series with the capacitor and switch?

pinout for the op amp is here
http://www.hobby-hour.com/electronics/lm386-power-audio.php
 
Engineering news on Phys.org
I don't see any short circuit there.
 
Between the 220uF capacitor and the dpdt switch. Isn't that a short? Or am I just a dumbass and forgetting something? Probably the later, heheh.
 
For there to be a short, the wire to the right of the 220 uF cap would have to connect to ground. This is not the case here, for either position of the dpdt switch.
 
Oh, a short when the switch is closed.
 
For there to be a short, the wire to the right of the 220 uF cap would have to connect to ground. This is not the case here, for either position of the dpdt switch.

I see, so for it to be a short, the diode section (where ground is) and the negative of the cap would have to be connected to the same thing.

Oh, a short when the switch is closed.

Yes, that's what my concern was since if it was a short, none of the signal from the guitar would be clipped.

Thank you for the help, guys.
 
You would have to include the diodes in the circuit like this:

[PLAIN]http://dl.dropbox.com/u/4222062/clipping%20amp.PNG

The output would be about 4 volts p-p and have more clipping on the positive half cycles than the negative half cycles for an input of more than 200 mV p-p assuming a gain of 20 from the 386.

You should see the LED flashing for high inputs.
 
Last edited by a moderator:

Similar threads

  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 10 ·
Replies
10
Views
3K
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
1
Views
4K
  • · Replies 1 ·
Replies
1
Views
10K
  • · Replies 27 ·
Replies
27
Views
6K
  • · Replies 1 ·
Replies
1
Views
7K
  • · Replies 6 ·
Replies
6
Views
3K