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  1. Audioguru

    right amplifier size for speakers

    A speaker rated for 160W "peak" or "maximum" power has a real power rating of 80W if it is the truth, or 20W if they exaggerate.
  2. Audioguru

    50w rms into 8 ohm load amplifier circuit using single dc power supply

    The datasheet of an LA4440 shows 19W at a horrible sounding 10% distortion. A graph shows 14W at 1% distortion that can be heard when its speaker is 8 ohms, its supply is 18V, it has a huge heatsink and both channels are bridged. Its output is 10W with low distortion when bridged. An LM3886 IC...
  3. Audioguru

    Power cuts and my solar power?

    Both of you. I went camping only one time, never again! My electricity is reliable so I never used an inverter or a generator. We cheer when the lights go out on a rare electricity outage. Web celebrate "Earth Day" for one hour in the evening each year with no electricity used.
  4. Audioguru

    Power cuts and my solar power?

    It sounds like you live on the moon. I have never seen such desolation except in a movie.
  5. Audioguru

    Power cuts and my solar power?

    Here in Canada, I am glad that only a few cars burn stinky, smokey diesel fuel. Nearly all trucks and buses use diesel and create lots of black smoke when they accelerate. I laugh when a diesel VW car is idling or running because it sounds like the terrible noises made by the engine is it...
  6. Audioguru

    Hi folks! I'm new here and don't understand JFETs

    I wonder what a 4.8Hz earthquake feels like? I have seen a subwoofer cone move at such a low frequency but I heard and felt nothing.
  7. Audioguru

    TTP223 Touch Sensor with LED Strip

    The ebay module with the sensor IC on it says no spec's. It might or might not have a 5V regulator on the module's circuit board.
  8. Audioguru

    Hi folks! I'm new here and don't understand JFETs

    The old vacuum tube preamp has a 1.5k cathode resistor bypassed with 22uF. The capacitor simply reduces the gain -3dB (half the output power) at the cutoff frequency and reduces lower frequencies at -6dB (1/4 the output power) per octave. The 1.5k with a 22uF bypass calculates the cutoff...
  9. Audioguru

    TTP223 Touch Sensor with LED Strip

    We are also guessing about if there is a 5V regulator on the sensor module.
  10. Audioguru

    TTP223 Touch Sensor with LED Strip

    He is not used a sensor IC, instead he is using a sensor module that might already have a 5V voltage regulator on it.
  11. Audioguru

    TTP223 Touch Sensor with LED Strip

    The datasheet of the touch sensor IC shows that its pin 1 "Q" is the output. But you have the pin 3 "I/O" touch electrode input wrongly connected to the Mosfet.
  12. Audioguru

    I don't understand the meaning/relevance of output impedance.

    Radio frequency amplifiers match impedances but modern audio amplifiers never match. The speaker resonates like a bongo drum and an amplifier with an extremely low output impedance damps the resonance very well so that the speaker faithfully produces the audio like it should sound. Look up the...
  13. Audioguru

    I don't understand the meaning/relevance of output impedance.

    Only an ancient old vacuum tubes amplifier has a 4 ohms output impedance. A modern solid state amplifier has an extremely low output impedance, and its damping factor is specified, not its output impedance. We do not know if its specifications say if it can safely drive a 4 ohms speaker or if...
  14. Audioguru

    I don't understand the meaning/relevance of output impedance.

    A linear amplifier with an extremely low output impedance still heats with about 45% to 55% of the power supply power when playing at about 50% of the power of clipping. In a Class-D amplifier, most of the power supply power goes to the speaker with only a little heating.
  15. Audioguru

    I don't understand the meaning/relevance of output impedance.

    When the damping of a speaker's resonances is reduced by a higher than very low output impedance of a solid state amplifier then the speaker resonates badly like a bongo drum. I think old speakers had good damping built into them so they did not resonate badly when driven from the fairly high...
  16. Audioguru

    I don't understand the meaning/relevance of output impedance.

    Modern very low output impedance amplifiers are solid state. Old vacuum tube amplifiers usually matched the output impedance of the amplifier to the speaker impedance.
  17. Audioguru

    Base resistor and MOSFET + Rectifier Diode Selection for Solenoid actuation?

    The datasheet for most Mosfets show that when the gate-source voltage is at the "threshold voltage" then the Mosfet is almost turned off. You want the Mosfet to turn on so look at the gate-source voltage when it is turned on.
  18. Audioguru

    555 timer

    The 100uF and 16k produce a pulse duration of only 1.8 seconds. 30 minutes has 1800 seconds. The maximum allowed resistor value is 20M so then the capacitor must be an extremely large and expensive low leakage film type.
  19. Audioguru

    Change in resistance of electret microphone with sound

    In your other thread you were also confused about an electret mic and how it works without reading about it. Its resistance is always there. Sound frequencies and loudness simply change (modulate) its resistance. An electret mic is a condenser mic with 48VDC permanently stored on its electret...
  20. Audioguru

    Car Radio Overheats, sound go out. Second radio same problem. Need help

    In an old Toyota you replaced all the speakers then replaced the original car radio (that had one wire of each speaker grounded) with a modern Pioneer car radio that must not have one wire of each speaker grounded. Then half of each of its four bridged amplifiers was DC and AC shorted to ground...
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