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  1. Audioguru

    Part Replacement in Circuit

    I am amazed that the circuit works when it was built on a solderless breadboard with messy long wires and their stray capacitance all over the place. His soldered circuit needed two long wires rolled up inside to add come capacitance and the antenna length was critical.
  2. Audioguru

    Why is it so hard to find ceramic capacitor kits that have a 3.3pF in it?

    His other post shows a theremin circuit with two 3.3pF capacitors in it to detect changes in the tiny capacitance of his hand's distance from an antenna. 3.3pF is almost nothing like the capacitance between your hand away from an antenna.
  3. Audioguru

    LM386 Amplifier Module help

    Peter's schematic of his LM386 power amplifier is also missing an important supply bypass capacitor but it does not matter since the ground pin 4 is not connected to the supply ground.
  4. Audioguru

    Taking Requests

    My wife and I cannot identify the name of the music.
  5. Audioguru

    Taking Requests

    I am glad to hear that you got rid of the hum (without an amplifier and microphone?). My wife is from Spain so we listen to a fair amount of flamenco music from acoustic guitar with absolutely no awful distortion. The acoustic guitar is slapped frequently. What happens when you slap an electric...
  6. Audioguru

    Taking Requests

    The 180Hz of fairly loud continuous interference is still there. It might be an input of 60Hz hum that is converted into a squarewave (180Hz) by the distortion circuit. Is the cable between the guitar and the overdrive circuit a shielded audio cable? Is the overdrive circuit powered from a...
  7. Audioguru

    Unveiling of the pedal

    I prefer the sound of an acoustic guitar. Electric guitars are rarely played clean because in "the good old days" amplifiers had tons of distortion and today they are trying to match that awful harsh sound. I think the circuit you have with diodes in the opamp feedback produces "soft" clipping...
  8. Audioguru

    Unveiling of the pedal

    Distortion adds many high frequency harmonics that sound harsh to people with good hearing but the distortion harmonics are reduced if people have poor hearing from old age or caused by playing loudly in a band or shooting guns in a war.
  9. Audioguru

    Unveiling of the pedal

    I am glad that it produces the awful distortion that you like and want. At the beginning of the recording before you play and at the end after you play I hear a 180Hz background noise. Your electricity is probably 50Hz, not 90Hz. Maybe your electricity is 60Hz then the interference is a...
  10. Audioguru

    Lessons Learned and When the Chips Are Down

    I haven't heard about Dick Smith's used car and electronic parts for years. Down Under student got parts and kits from him.
  11. Audioguru

    Lessons Learned and When the Chips Are Down

    A metal ring terminal on top of the foil can be bolted to the box and connected to the circuit's ground (the negative battery terminal).
  12. Audioguru

    Lessons Learned and When the Chips Are Down

    I corrected the tone control circuit so you can turn down the fizz. The circuit designer did not know that C3 had its polarity backwards and also did not know that an opamp NEVER has a capacitor to ground on its output which happened if the original tone control was turned to produce no highs...
  13. Audioguru

    Piezo buzzer operation

    Amazon sells cheap clothing and shoes. I didn't know that their sellers break apart cheap Chinese piezo beepers then sell the piezo wafers. Oh, defective piezo wafers? Then I guess Amazon sells anything.
  14. Audioguru

    Lessons Learned and When the Chips Are Down

    I use Microsoft PASTE program to copy and paste schematics. There is no schematic in this thread but here is the one you gave-up on and was in the video in the other thread:
  15. Audioguru

    Lessons Learned and When the Chips Are Down

    Since the diodes produce distortion, not the opamps then the differences in opamps is noise (hiss) and high frequency response (some old opamps like the 741 cannot properly produce the highest octave in hearing, 10kHz to 20kHz). Original electric guitar amplifiers used vacuum tubes that have a...
  16. Audioguru

    Lessons Learned and When the Chips Are Down

    The circuit with one "LM741" opamp and 3 diodes uses the opamp for its voltage gain, not for distortion. It is the diodes that cause the clipping distortion. If the input signal level from the guitar is too low and/or if the gain of the opamp is set too low then the output of the opamp will have...
  17. Audioguru

    Piezo buzzer operation

    We simply buy a piezo beeper, nobody makes it themself. To make one you must buy the piezo beeper then break it apart to take the 3-terminals piezo disc that is not sold by itself. Then you must go to school to learn how to make a very simple transistor amplifier. You will learn how to select...
  18. Audioguru

    Piezo buzzer operation

    An oscillator does not work with magic, instead it works from a battery or power supply providing energy to a transistor amplifier that drives and takes feedback from the piezo. A piezo buzzer or beeper has a transistor in it and it produces the frequency of the piezo in its resonant housing.
  19. Audioguru

    LED and Switch for circuit

    The original old schematic still has the polarity of C3 backwards. The circuit produces distortion only if the output signal level is high enough which depends on the input signal level and the gain setting. The LED will light and slowly kill the little battery all the time the power switch is...
  20. Audioguru

    Need help interpreting something on a schematic

    The 4558 is popular in pedal circuits because it old but is better than the very old 741 or dual 1458. Any opamp uses two resistors (or a pot) to set its gain. Opamps designed 60 years ago (LM308 in your other thread) needed an external frequency compensation capacitor because in those days they...
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