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  1. Audioguru

    Electric ICE Exhaust Cut-out... why? and how?

    The cop I see every day catches speeding cars with a radar gun that senses the cars two blocks away, and he selects mostly "performance" cars. His normal hearing senses the noisy cars more than two blocks away. He gives both of them expensive tickets. I thanked him. I complained to...
  2. Audioguru

    Digital music player with a Tivoli Audio Model One

    If you play acid rock at full blast all the time then your 5W speaker might be damaged with the continuous 12W. 6W at low distortion is 12W at high distortion (clipping like crazy) because all the distortion harmonics add another 6W.
  3. Audioguru

    Ferrite rod antenna explanation

    Of course the ferrite loopstick antenna is an RF transformer. The winding that is tuned with a variable capacitor has a high impedance at the tuned frequency and has many winding turns and the other windings have fewer turns so that they are lower impedance and do not load down the bandwidth of...
  4. Audioguru

    Replace variable capacitor with varicap

    "Detail" of sounds is high frequency response. When humans are young we can hear as high as 20kHz and CD players and MP3's produce it. FM radio goes to 15kHz and sounds good. But an ordinary AM radio MUST cut the 10kHz interference beat frequency produced by adjacent stations and ordinary...
  5. Audioguru

    Simple NiMH Charging Circuit and Resistance

    Modern Ni-MH batteries made by Eneloop (Sanyo/Panasonic), Energizer and Duracell hold a charge for one year and are sold precharged. They do not recommend trickle charging if you want them to last for 5 years. 0.1C is a recommended overnight (10-14 hours) charge rate for Ni-MH batteries. If you...
  6. Audioguru

    Need cover housing for a speaker of 30mm

    The tiny 1.25" speaker is a squeaker, not a loudspeaker. Its resonance will be 300Hz or higher with no low frequencies.
  7. Audioguru

    Exhaust Switch Project HELP!!

    This and most other forums forum do not allow threads about breaking the law. Also, a noisy car is stooopid!
  8. Audioguru

    Simple NiMH Charging Circuit and Resistance

    Energizer battery company and a Japanese one say that a Ni-MH battery must have a trickle charge no higher than 1/40th its mAh rating to avoid damaging the battery. 1/40th of 2500mAh is 62.5mA.
  9. Audioguru

    Exhaust Switch Project HELP!!

    Why do you think it is "cool" to make your car produce loud noise?? A car for civilized people is built with a muffler to make it quiet. On a street near my home a policeman catches speeding cars and noisy cars and gives them expensive tickets. Cool?
  10. Audioguru

    Digital music player with a Tivoli Audio Model One

    With a 9V supply, the PAM8610 amplifier will produce 6W into 4 ohms from one channel with fairly low distortion. But 6W sounds only a little louder than 2W or 3W. 20W sounds twice as loud as 2W because our sensitivity to loudness is logarithmic. If you play music and the peaks are 6W then the...
  11. Audioguru

    Ferrite rod antenna explanation

    This is an extremely simple radio with only ONE LC tuned circuit. If the tuned coil has many more turns than the coil that feeds the transistor then the bandwidth is narrower resulting in less interference from other radio stations but high audio frequencies will be reduced. Then YOU must decide...
  12. Audioguru

    Can I use resistor instead of pot with LM386?

    Guess what I noticed:
  13. Audioguru

    Push button controlled LED decade counter ...

    A CD4017 does not have an internal clock oscillator. A pushbutton, a resistor and a capacitor can cause it to sequence with each push if the pushbutton is debounced. Output #1 on the first CD4017 can be the clock for the second CD4017.
  14. Audioguru

    Wiring 5v to a 12v powersupply

    Are you vaping with an electronic cigarette?
  15. Audioguru

    Wiring 5v to a 12v powersupply

    Ripple from the LM2596 will be its output voltage jumping up and down at its 60kHz switching frequency and lower frequency discontinuous mode switching. Many audio and video loads do not work well when there is that much ripple. You never said what the "something device" does.
  16. Audioguru

    Li ion battery charger, adapting power bank

    Look at the battery in the power bank. Isn't it much more than the 800mAh of the little battery you want to charge? Like 3000mAh? Then the charger will seriously over-current the little battery which might cause it to explode and/or catch on fire. Have you ever seen the metal Lithium burn? A...
  17. Audioguru

    Can I use resistor instead of pot with LM386?

    The datasheet for the UM66 shows an output of 0.8V peak at 600uA. The maximum peak output of an LM386 driving an 8 ohm speaker when the supply is exactly 9V is 3V peak. Then the maximum gain must be 3V/0.8V= 3.75 times but less when the battery voltage drops. But the LM386 in the circuit with C2...
  18. Audioguru

    Li ion battery charger, adapting power bank

    A power bank uses a battery much more powerful than the little 800mAh battery so its charging current will be much too high.
  19. Audioguru

    Bicycle generator

    A lithium battery overcharging could set fire to your entire neighbourhood or town. Insurance won't cover the damage.
  20. Audioguru

    Wiring 5v to a 12v powersupply

    Some cheap Chinese ebay circuits are not certified to be safe (banned in Illinois?). My Electrical Utility Company gave away free compact fluorescent light bulbs so that people could try them and use less electricity than old incandescent light bulbs. But the new bulbs dripped burning plastic...
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