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  1. Audioguru

    Design bass amplifier

    I have a clock radio in the bedroom. Its 3" speaker sounds awful so I connected a Radio Shack enclosed 2-way speaker I modded to it and it also sounded awful. I increased the values of the radio's coupling capacitors and now it sounds great. I modded the speaker by throwing away its garbage cone...
  2. Audioguru

    Design bass amplifier

    He is using those lousy speakers.
  3. Audioguru

    Design bass amplifier

    The spec's for the Panasonic home theater 6.5 inches in diameter "subwoofer" say 141W with 1% distortion at 40Hz to 198Hz (-10dB). But at -10dB it is barely working so it is NOT a subwoofer and is not even a good ordinary woofer. ALL the speakers for this home theater are 6.5" in diameter. The...
  4. Audioguru

    Full Wave Rectifier

    That is why I never look at "direction of current flow". Instead I simply look at the polarities. A diode has an arrow, a transistor emitter also has an arrow. The arrow is pointing at the negative wire when the diode or base-emitter junction conducts with forward current (a zener diode is used...
  5. Audioguru

    Full Wave Rectifier

    The drawing shows voltage polarities. Electrons flow from negative to positive. A diode conducts when its anode is positive and its cathode is negative. When the polarity across the diode is reversed then it does not conduct.
  6. Audioguru

    AC 18650 Replacement?

    The datasheet for the Cree CREE XM-L2 LED does not have a current limiting circuit. Whoever made the flashlight added a current limiting circuit and a heatsink but we know nothing about it.
  7. Audioguru

    Design bass amplifier

    The TPA3116d2 amplifier produces 20W per channel at low distortion into 8 ohm speakers when the supply is 20V. It produces 20W per channel at low distortion into 4 ohm speakers when the supply is 14V. A small heatsink is needed but I do not know how to mount it and I don't know if you can solder...
  8. Audioguru

    AC 18650 Replacement?

    An 18650 lithium cell is 4.2V when fully charged and can provide at least 30A to blow that 3A LED to smithereens if nothing limits the current. The flashlight must already have a resistor or something to limit the current. But it will be difficult to find a power supply that provides 3.7V to...
  9. Audioguru

    Design bass amplifier

    Some class-D amplifiers are pretty good. Others are cheap, make bad sounds and are low power.
  10. Audioguru

    AC 18650 Replacement?

    The 3000mA rating of the LED is the absolute maximum allowed current when it is cooled with liquid nitrogen or something so that its metal base is cooled to 85 degrees C. How does the flashlight cool it? Maybe 700mA will cook it. You need to measure its current in the flashlight to know.
  11. Audioguru

    Mosfet gate voltage

    Do not talk about a Mosfet being saturated or not. Simply say if it is fully turned on or if it is turned off. If its datasheet says that its gate-source voltage must he 10V then believe it or buy thousands of them and hope that you find one more sensitive than most of them. Many "logic-level"...
  12. Audioguru

    Help me in schematic diagram...

    I have never been there and do not understand why it is allowed to happen there. I cannot remember when the last blackout occurred here. Years ago. We celebrated.
  13. Audioguru

    Help me in schematic diagram...

    Why does your electricity have blackouts?
  14. Audioguru

    Design bass amplifier

    Digikey is a large American electronic parts distributor. They say the tDA2030 and the TDA2030A are obsolete and they have none. A 6 ohm load causes double the current in a bridged amplifier so each amplifier must be able to drive 3 ohms. An LM3886 amplifier IC is available and can drive the 6...
  15. Audioguru

    Replace variable capacitor with varicap

    Please post a link to the webpage that has this horrible circuit.
  16. Audioguru

    Design bass amplifier

    An LM1875 is still made and is similar to a TDA2030. Its minimum supply is 16V producing about 4W into 8 ohms. Maybe 10W is better then the supply can be 30V. An LM3886 is nice with a 70V supply and an output of 50W to 62W into 8 ohms.
  17. Audioguru

    Design bass amplifier

    I knew that a TDA2030 was obsolete but today I am surprized to see that the TDA2030A is also obsolete. If you can find one then 12V is its minimum supply where its output to an 8 ohm speaker is only 2W or 3W. The power vs supply voltage graph in its datasheet begins at 24V where its power into 8...
  18. Audioguru

    Replace variable capacitor with varicap

    An audio amplifier is used to play a high impedance audio signal source into a low impedance transducer like an earphone or a speaker. An LM386 is designed to drive an earphone or a speaker. But your circuit does not demodulate the radio signal so it has no audio. A demodulator for AM is a...
  19. Audioguru

    Design bass amplifier

    In LTspice, you selected an Opamp2 that needs an additional external spice file that details it. Simply delete it and use "opamp" that is directly ahead in the list of opamps.
  20. Audioguru

    Power source for smoke detector

    I suppose the "2" was a typo?
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