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  1. audioguru2

    confused about voltage regulator spec

  2. audioguru2

    are these pins shorted????

    The resistance between pins 7 and 8 is about 1M and is used to self-bias the inverter to be a linear amplifier. Shaiq's IC is shorted between pins 8 and 9.
  3. audioguru2

    sending a beep into the telephone line???

    If you don't use a transformer then the 555 circuit must be battery operated to avoid unbalancing the phone line causing mains hum. Diodes will protect the 555 in the moments when the relay contacts are flying. Without the relay contacts then the protection diodes short the ringing voltage.
  4. audioguru2

    Stereo Audio power amplifier 2 x 40W - 80W

    The M250 looks like another good modern amplifier. It has enough paralleled output transistors to produce high power in a 4 ohm speaker.
  5. audioguru2

    Stereo Audio power amplifier 2 x 40W - 80W

    Find an amplifier designed for parts available in your country. In Canada, I can buy any transistor I want, except some Oriental ones are hard to get.
  6. audioguru2

    Stereo Audio power amplifier 2 x 40W - 80W

    Even if you used high voltage output transistors with a dual 60V supply, the peak current into an 8 ohm speaker is only about 7A which all power transistors can pass. But transistors will melt due to the high power in them, so need to be paralleled. Here is a pretty good 150W amplifier (into 8...
  7. audioguru2

    sending a beep into the telephone line???

    Hi Shaiq, A telephone line is a balanced pair of wires. The balance must be maintained by connecting your circuit to both wires through an audio transformer or operating your circuit from a battery. The DC voltage on the telephone line is maintained by capacitor-coupling your...
  8. audioguru2

    Stereo Audio power amplifier 2 x 40W - 80W

    Make the 1st amplifier if its power output and distortion are acceptable to you. Changing its output transistors won't increase its power output. The supply voltages for the 1st amplifier from a dual 24VAC transformer are about plus and minus 32V while they are plus and minus 36V for the 2nd...
  9. audioguru2

    confused about voltage regulator spec

    You can buy a lot of voltage regulators. 7805 is 5V, 7809 is 9V, 7812 is 12V and 7815 is 15V. You can buy them in a small plastic case and their max current is 100mA or a larger TO-220 case that can be bolted to a heatsink and their max current is 500mA and 1A. Current in a load resistor...
  10. audioguru2

    Stereo Audio power amplifier 2 x 40W - 80W

    This amplifier produces a little more power than the other amplifier you showed and both operate in class-AB. Class-A creates too much heat and class-B has crossover distortion.
  11. audioguru2

    Stereo Audio power amplifier 2 x 40W - 80W

    It looks like an old design, not very good performance and uses mostly Oriental transistors. The input transistors look like they are mounted backwards. Draw a schematic, cut its pcb in half and make it if you want, but there are many newer and better amplifiers designs on the internet.
  12. audioguru2

    Sine wave Inverter Project

    This thread talks about sine-wave inverters, not the amplifier in your other thread.
  13. audioguru2

    Sine wave Inverter Project

  14. audioguru2

    Convert 0-30V 3A PSU to 5A or more

    Didn't you use parts listed in the original project? There is a thread in the Projects Q/A Forum that discusses the problems with those parts and recommends changing some to get 3A at 30V reliably with good regulation. Kain used parts recommended in this thread for 30V at 5A reliably with good...
  15. audioguru2

    Sine wave Inverter Project

    I said that if a wave-shaper is used at the output then the load must be a high impedance which takes no power output.
  16. audioguru2

    ISS108 diode information reqest

    HI ante, Didn't you see my link to the Japanese guy's website? http://www.interq.or.jp/japan/se-inoue/e_ckt27.htm
  17. audioguru2

    0-30 Vdc Stabilized Power Supply

    Q2 doesn't need a rating of 15A and 115W, but a 2N3055 transistor will work fine. I can buy a TIP31A power transistor for $.68US and a 2N3055 power transistor for $1.68US. There are many power transistors with ratings and prices like a TIP31A.
  18. audioguru2

    ISS108 diode information reqest

    Hi Ante, Usually I just press the keyboard's "Prt Scrn" button to copy what is in a link then paste the image into MS Paint where I crop and title it.
  19. audioguru2

    Audio/Sound Amplier

    The input to an amplifier needs shielded audio cable. The connections of the circuit must be with very short wires so a breadboard is not good. The wires act like "antennas" and pickup mains hum and buzz and other interference.
  20. audioguru2

    ISS108 diode information reqest

    Sorry, your frequency is far too low. The LC resonates at 2.140MHz and the circuit produces 1.5mA at 30VDC. I found the project and its test results here: http://www.interq.or.jp/japan/se-inoue/e_ckt27.htm
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