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  1. Audioguru

    Peak detector for piezo drum pad

    Can't you read datasheets? The 741 opamp design is 50 years old and was designed to use a plus and minus 15V supply. Its inputs do not work anywhere near a supply voltage and its output does not swing much.
  2. Audioguru

    Peak detector for piezo drum pad

    Why not look at the datasheet of an old NE5532 to see that the Minimum Supply is 6V (+/-3V)? Without a negative supply then the inputs do nothing if their voltage is less than 2.9V with a 6V supply and the inputs barely work at about 2.9V to 3.1V. With a load of 2k ohms then the output also...
  3. Audioguru

    Peak detector for piezo drum pad

    your very old NE5532 opamps do nothing because they are not powered on your schematics. They probably need a positive and negative dual polarity supply.
  4. Audioguru

    Designing a complete active speaker box

    Your power supply is not plus and minus 12V, it will short circuit itself. Why do the filter opamps need 24V anyway? Use the 12V to feed a 7809 and use the +9V to power the filter opamps. Simply bias the (+) input of each opamp at a filtered 4.5V with a voltage divider. Capacitor couple the...
  5. Audioguru

    Noise reduction .

    The pop sound is a coupling capacitor charging or discharging quickly. The output of the guitar and the inputs of each amplifier must be modified a little so that there is 0VDC on the switch. If you switch while playing then a POP might be produced since you might suddenly switch at a peak...
  6. Audioguru

    Electret headphones amplifier

    You do not want a mains transformer or an audio transformer in a good audio circuit. You also do not want a thermistor limiter. The head-fi.org thread has an acoustical frequency response curve that might have no bass due to poor coupling/sealing or a lousy mic. Some transformers cut bass and highs.
  7. Audioguru

    Noise reduction .

    Why don't you draw a schematic and attach it to your reply? Audio signals use shielded audio cable where the shield is connected to the circuit ground at each end. The shield blocks hum and other interference. You said "noise" but did not describe it. Rock "music" and loud cars and motorcycles...
  8. Audioguru

    Adding motor into simple circuit

    A large battery cell can provide much more current than a small battery cell. The current drawn by your motor overloaded your battery because the motor is too powerful using too much current that your battery could provide, because the battery was too old or poor quality, or because the battery...
  9. Audioguru

    Adding motor into simple circuit

    You must select a motor and batteries that are not overloaded. Try three new AAA alkaline cells, then AA, then C then D.
  10. Audioguru

    Adding motor into simple circuit

    Obviously, the battery cannot supply enough current to operate the motor plus the sound module. Use a more powerful battery. American and European batteries are powerful, Chinese batteries are garbage. Carbon-zinc and Super Heavy Duty batteries are also garbage. AAA cells produce very low...
  11. Audioguru

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Everything I have made and my purchased TVs and sound systems do not have fuses.
  12. Audioguru

    Correct Motor Help

    I saw a little kid (10 years old?) riding an electric skooter. Each small bump in the sidewalk almost dumped him. I could easily outrun it on my feet. Google shows a couple of skateboards powered by a jet turbine engine.
  13. Audioguru

    Correct Motor Help

    The motor power and method for it to drive the wheels with pulleys or gears is determined by electric vehicle experts, not us electronic circuit experts. Electric vehicle experts can tell you which motor they recommend and where to buy one. The speed control and maybe braking for the motor is...
  14. Audioguru

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Continuity between primary and secondary would be when they are shorted together. One ohm-meter probe on the unpowered primary wire and the other ohm-meter probe on the secondary wire and with no continuity then the meter will read infinite Ohms. I have never used a toroid transformer and I...
  15. Audioguru

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    If the toroid has a piece of metal in it attaching it to something then the metal is a shorted turn around the toroid core. If the primary winding, the secondary winding or the winding you added to power your meter has one turn of wire shorted to a turn of wire beside it then the transformer is...
  16. Audioguru

    Correct Motor Help

    This is a website for electronic circuits. You should find a website for powered skateboards/rollerblades.
  17. Audioguru

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    The transformer secondary or the extra windings around it that power the meter probably has a shorted turn. EDIT: Isn't the transformer a toroidal type? Then is its mounting method shorting its core?
  18. Audioguru

    Correct Motor Help

    Skateboards and roller blades are used by lightweight kids. Your weight determines the power needed from the motors.
  19. Audioguru

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Maybe badluck made you turn on the project twice when the mains was at the peak voltage and maybe 2 seconds between turn ons did not let the fuse cool enough.
  20. Audioguru

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    When the project has no load then the 28V transformer produces 29VAC which is rectified and makes +40V. Then the heating in R1 is (40 squared)/2200 ohms= 0.73W. A 2W resistor will be fairly warm. R2 is part of a half-wave rectifier so it draws current for half the time and is in a voltage...
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