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  1. Audioguru

    A Stretch

    In addition to him using a dual TL082 opamp instead of a single TL081 opamp, the opamp is not powered in the schematic and the polarity of C3 is backwards. The distortion sounds AWFUL!
  2. Audioguru

    Control Yamaha HTR-5660 with Raspberry Pi

    The old audio receiver is controlled with switches and knobs to be used by your hands. Why control it over a network? My Yamaha audio receiver is a little older than yours and its switches have worn out so it does not work anymore.
  3. Audioguru

    Design fix on a battery powered COB LED

    Two AAA batteries make 3V only when they are brand new. Their voltage begins dropping the moment you start using them. A voltage boost converter might not work when the battery voltage is only 2V or less and since the LEDs use Power then the battery current will be much higher then the voltage...
  4. Audioguru

    Design fix on a battery powered COB LED

    Did you measure the battery voltage as the LEDs were slowly dimming? The dimming was caused by the small overloaded batteries dying.
  5. Audioguru

    Design fix on a battery powered COB LED

    You have nothing in series to limit the LED current so of course that are too bright with new batteries which kills the batteries and dims the LEDs before you want. An LED needs its current limited by a series resistor or a constant current circuit. We need to know the voltage (color) of the...
  6. Audioguru

    1960? B.C. (before cassettes)...

    The first computer I worked with used punched cards for the program and tiny ferrite cores on a matrix of wires for RAM. Its logic ICs were RTL and DTL. I think it was in 1968.
  7. Audioguru

    LI-ION 18v Battery Pack

    Because they are cheap and came from "you know where".
  8. Audioguru

    Quick n Dirty answer needed

    Every time somebody makes a circuit on a solderless breadboard, we cannot see which connects to what and it does not work.
  9. Audioguru

    Quick n Dirty answer needed

    I guess the LED and/or 555 is/are burned out because of a missing current-limiting resistor in series with the LED.
  10. Audioguru

    Implementation of Amplifier in LTSpice

    My simulation shows the DC voltage feeding the output coupling capacitor saturated at +9.9974V without negative feedback and a reasonable lower DC voltage with some DC negative feedback. Q8 does not have enough base current since without negative feedback its base voltage is only 0.316VDC.
  11. Audioguru

    Implementation of Amplifier in LTSpice

    As I said in the other forum, you cannot make a high gain amplifier without any DC negative feedback because the tiny offset voltages are amplified 1500 times.
  12. Audioguru

    Power supply downgrade

    Eight AA cells might be used to produce +6V and -6V.
  13. Audioguru

    Quick n Dirty answer needed

    1.8V red LEDs in series strings of 4 LEDs with a 75 ohm resistor and five of these strings driven by a 555 slasher circuit will show how quickly a little 9V alkaline battery will slowly dim the LEDs then die.
  14. Audioguru

    Quick n Dirty answer needed

    To flash a number of LEDs from a 555 you need a power supply or a huge battery. What is your choice? What voltage? How many red LEDs around the heart and how many LEDs flashing the initials? What are the forward voltages of the different LED colors you will be using?
  15. Audioguru

    Tapping leds into 12v radio(Amps)

    Your truck is different to the cars I had. In my cars, the ignition switch turned the engine on and off. The radio could play even with the engine turned off because the radio had its own on and off switch. You can connect the LED controller box to your ignition switch if you want.
  16. Audioguru

    Tapping leds into 12v radio(Amps)

    If you connect the LED controller box to the 12V feeding the radio then the LEDs will be turned on all the time when the radio is on or is off. Basically you are connecting the LED control box directly to the car battery. Maybe you want the LEDs to light only when the radio is turned on then the...
  17. Audioguru

    Quick n Dirty answer needed

    In the third circuit, the red LED does not light because its forward voltage is less than the white, green and blue LEDs causing all the unlimited current to burn it out the instant the battery was connected. In the video I did not see a 100 ohm current limiting resistor but I saw a 1k resistor...
  18. Audioguru

    Is hand sanitizer electrically conductive ?

    Circuits that are used to detect when the water level is low for plants use AC, not DC. DC causes plating and corrosion of the probes.
  19. Audioguru

    Quick n Dirty answer needed

    The kid from India has 19 thousand subscribers. You Tube pays him 19 thousand rupees when all subscribers look at the ad then look at one of his videos. We are not his subscribers but maybe he is also paid by You Tube when we look at the ad then look at his awful video.
  20. Audioguru

    [Beginner] Having trouble using one momentary switch to activate multiple oscillator circuits.

    Of course the oscillators interfere with each other without using an audio mixer circuit. Usually an inverting opamp is used for an audio mixer circuit. Then the inputs are all completely isolated from each other. Here is a circuit:
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