Search results

  1. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Oz, Welcome to our forum. I am sorry to hear that your power supply project has failed. U2 has overheated because: 1) Maybe the supply voltage is too high for it. Which opamp did you use? What are the ratings of the power transformer? 2) Q1 is connected directly to the output...
  2. audioguru2

    ELM - Pocket Size MP3 Player

    Hi Ante, About 1/4 of the way down, Building Main Circuit Board, I cannot go to the "wiring technic page".
  3. audioguru2

    Who is using the oldest computer?

    You did what?
  4. audioguru2

    Guitar Amplifier

    Hi Blacksheep, Which preamp did you build, and please explain what in its sound sounded "dirty". Hum or buzz, distortion?
  5. audioguru2

    detector prototype

    Hi Badai, Have you built your detector yet? A good coupling path is short, directionable and without obstacles. Antennas should have the same polarization (turn your AM radio around and hear the difference). A poor coupling path is from here to the planet Pluto, with the Sun in between! (or...
  6. audioguru2

    Guitar Amplifier

    Hi Darrin, Toobs and output transformers? Yeah, I remember those. Some transistor amps have vacuum tubes glowing just for show, since their tubes aren't connected to the amp's circuit!
  7. audioguru2

    Connecting An Audio Output to 20 Headphones...

    Hotwaterwizard, Thanks for the good mic mixer circuit. I like the way that it uses an opamp to provide a "VR" supply voltage for the electret mics.
  8. audioguru2

    ELM - Pocket Size MP3 Player

    Hi Wellington, I like the way that he soldered all those tiny wires to the pins of those surface-mount LSI chips. Too bad the links don't work because I would like to doo dat too with surface-mount chips.
  9. audioguru2

    Audio Signal Switch

    MP, I dunno about guitars, but my experience has proven that 4016, 4066 and 4051 chips make pops in microphone switching circuits. The "charge injection" is internal and cannot be slowed external to the control pin. In 1996, MAXIM introduced their low-cost improved MAX4066, with much lower...
  10. audioguru2

    Connecting An Audio Output to 20 Headphones...

    Hotwaterwizard, Thanks for posting your headphones amp circuit and datasheet. It is really appreciated to see how things can be done differently. I am sorry that we didn't acknowledge your post, it is because the topic's author decided to use an amp that he already had, a few days before your...
  11. audioguru2

    Switch Transformer

    Hi Quantum, I'll try to answer your questios: 1) To reply with a quote, login, then click Quote on the reply that you want to be quoted. Delete what you don't want, then reply below the quote. 2) For battery current/life, I looked at a battery manufacturer's datasheets. For a 6.0V end voltage, a...
  12. audioguru2

    Switch Transformer

    Quantum, 3 paralleled little 9V batteries are good for only about 60mA. Therefore their power output is only about 1/2 Watt. The inverter will have some loss, so its output power will be less. If you power it from a car battery, then its output voltage will be too high, but it will still be...
  13. audioguru2

    pulse width modulation

    The CMOS inverters in a 2-inverter oscillator have a voltage gain of about 100 each. Therefore the charge/discharge of the capacitor is amplified 10,000 times, plus the circuit has positive feedback to speedup the switching even more. The outputs of all the 2-inverter oscillators that I have...
  14. audioguru2

    Audio Signal Switch

    MP, Yes, 4016, 4066 and 4051 chips switch line-level audio, music and effects quite well. But since a microphone has a level that is 100 to 200 times smaller, then noise and pops are very noticeable. On TI's datasheet for their CD4016, page 3 and figure 20 on page 5 show that the Crosstalk from...
  15. audioguru2

    Generators

    Steven, If you get your voltage high enough then anything will conduct, including those penguins! ;D
  16. audioguru2

    Switch Transformer

    Quantum, Inverters use a transformer "connected backwards" to step-up a low AC voltage to 120VAC. The low-voltage winding is usually center-tapped to keep the driving circuitry simple, and the output is square-wave instead of sine-wave. The driving circuitry is an oscillator with opposing...
  17. audioguru2

    Connecting An Audio Output to 20 Headphones...

    Shahrier, Relays and switches with gold-plated contacts will mention their use in "dry" (very low voltage) circuits. They will say "AU clad or AU flashed", and are usually limited to 24 or 30VA. A silver-plated high-current contact relies on high voltage or high current to burn off the...
  18. audioguru2

    Generators

    Quantum, Actually, that is the work of Steven, as reported by Mixos. I was going to mention those penguins too. With that much high voltage, they will fly! Have you ever seen a penguin fly? They can't, look at those tiny wings. Notice that Steven uses his finger instead of a voltmeter. Ouch!
  19. audioguru2

    Levitating Globe

    Mazzag, Yeah, sure. But if a big magnet above an iron globe pulls it up, what causes it to stop pulling so much when the globe is levitating? If you put a magnet above and another magnet below, then the globe will be attracted to the nearest one, and wouldn't stay in between. I don't see any...
  20. audioguru2

    pulse width modulation

    Kevin, If the output of your 2-inverter oscillator is bad, then perhaps you are not using a series resistor that has a high enough value (10K minimum). Also, maybe your output is from the wrong inverter.
Top