Search results

Search Forums New Posts
  1. Audioguru

    Is a motor also a dynamo?

    Your video is too fuzzy to see anything. The video sounds like you are spinning the motors mechanically very slowly. You provided no details about the motors or your circuit: 1) Are the motors DC with permanent magnets? 2) How many volts do they normally run at? How many volts (from a battery?)...
  2. Audioguru

    ISO amp that drives the old JBL's 100's-I

    I found a video of the Pioneer receiver and it seems to be much newer than the old speakers. Simply fiddle with the tone controls to make it sound the way you like.
  3. Audioguru

    ISO amp that drives the old JBL's 100's-I

    Old speakers were designed to be driven from the fairly high output impedance of a vacuum tubes amplifier. The damping was poor and allowed a cheap speaker to sound boomy or a good speaker designed for it to have a loose flat low frequency response. But a modern solid state amplifier has an...
  4. Audioguru

    ISO amp that drives the old JBL's 100's-I

    JBL was bought by Harman who was bought by Samsung. They have a new JBL L100 this year and its sensitivity is 90dB at 1W at 1m which is LOUD. If it is 8m away then you need 64W. If you want 120dB then you need thousands of Watts. Editted.
  5. Audioguru

    Need a little inspiration

    My RC Li-PO batteries are at full charge for most of the summer and at storage charge all winter. They last for years.
  6. Audioguru

    Using an oscillated capacitor as a transistor

    Your circuit does not amplify anything. The resistors reduce the level of the oscillator in the earphone and the capacitors simply pass the signal like pieces of wire.
  7. Audioguru

    How do I amplify a low Amp signal (12 v, 100 mA) to 12 v 3.0 Amps?

    A bridged amplifier uses two amplifiers, each one drives one wire of the speaker. The voltage swing across the speaker is almost doubled then the current in the speaker is also almost doubled resulting in almost 4 times the power in the speaker with the same supply voltage, as a single...
  8. Audioguru

    How do I amplify a low Amp signal (12 v, 100 mA) to 12 v 3.0 Amps?

    For 33W RMS into 4.4 ohms the power amplifier must have a power supply that is 37VDC or a little more. If the amplifier is bridged then the supply can be about 19VDC.
  9. Audioguru

    Integrated Circuits

    I am amazed that, "a modern chip may have several billion transistors in an area the size of a human fingernail." Try doing that with discrete components.
  10. Audioguru

    Learning Project Help - Converting a full sized solar panel

    I found a box full of some cheap cigarette lighter type of 5V USB units thrown away. I took one to see what the Chinese people put in them but it was all burnt inside. They are not reliable and might burn down your solar panel.
  11. Audioguru

    Learning Project Help - Converting a full sized solar panel

    I have a solar panel made to trickle charge a car battery. Its current is rated at 13.2V and its open circuit voltage at noon in summer is 18V. His solar panel higher voltage might power a battery charger circuit.
  12. Audioguru

    Learning Project Help - Converting a full sized solar panel

    Driscolldb said that he wants to top up the charge on products that have a charger inside them and that charger is powered from USB 5V, not to charge batteries without using a proper charger circuit. I assume his solar panel produces 18.2V when it is fully loaded at 5.49V. Then when it has a...
  13. Audioguru

    Battery pack diy advice please

    Two parallel batteries are used in products that must keep the battery power all the time. The product warns you that it has "Low Baddry" so you replace one cell at-a-time.
  14. Audioguru

    Hello, can somebody help wich transistor is like bfg520

    You should label the images of the oscilloscope about where they came from. Was the fist image from C8? Where did the lower level second image come from? Of course the LC resonant circuits must be tuned to your input frequency of 10.7MHz. I did not calculate the resonant frequency because I do...
  15. Audioguru

    Hello, can somebody help wich transistor is like bfg520

    Where did you measure the two different signals? C8 produces only one signal. Good, you have an audio output at 1kHz. But its level is very low and it is very distorted, the same as when my FM clock radio is not tuned to the center of the radio frequency. Try increasing then decreasing the...
  16. Audioguru

    Hello, can somebody help wich transistor is like bfg520

    I do not have time to talk about this simple circuit in 220 posts. FIRST you need to learn English. SECOND you need to learn electronics basics. THIRD you need to learn about radio circuits. FORTH you need to learn about the simulation program.
  17. Audioguru

    Hello, can somebody help wich transistor is like bfg520

    Why are you making a simulation when you do not understand how to set up the simulation? The "timebase" for the oscilloscope of the simulator is set with the TRAN command. Here is how to set TRAN (right click on it) to show the 1kHz demodulated waveform on C8: Stop Time: 100m Time to start...
  18. Audioguru

    mpf102 duds

    The sellers on ebay go to the garbage bins at the back of Chinese manufactures and take the defective parts that were thrown away and sell them on ebay. Some Chinese manufacturers copy a Western part but get the pins sequence wrong.
  19. Audioguru

    Hello, can somebody help wich transistor is like bfg520

    Your "oscilloscope" timebase is very fast at 0.5us per division and shows a tiny 5MHz waveform on top of a much lower frequency. To see the 1kHz demodulated waveform then the timebase must be much slower at maybe 1ms per division.
  20. Audioguru

    Hello, can somebody help wich transistor is like bfg520

    Your LM386 is a mess and I think your simulation program does not know what it is. Delete it and have the sim program show you the signals at C8. You have C4 and C5 at 0.01uF which is 10,000pF. All other discriminators and your old ones have 200pF.
Top