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  1. Audioguru

    DC 9v replacement

    Having an adjustable voltage on an adapter is asking for something to be blown up by it.
  2. Audioguru

    DC 9v replacement

    Stereo was not mentioned, I assume the speaker is mono. With a 9V supply and one linear single ended amplifier feeding an 8 ohms speaker, the power output is 1W and the heating is an additional 1W so the total is 2W. A 9V/0.25A adapter or even more current is fine. If the speaker is 4 ohms then...
  3. Audioguru

    DC 9v replacement

    When you shop for an AC/DC adapter, the very important polarity of the jack on the receiver shown in the manual must be matched by the plug on the adapter.
  4. Audioguru

    Regulating output of a 5252f?

    BEWARE! That site has a VIRUS on it. I used CTRL ALT DELETE to get out of it then I changed my User.
  5. Audioguru

    Regulating output of a 5252f?

    A similar solar garden light IC Prema PR4403 is from Germany. Its datasheet says that its switching frequency is 500kHz. Then the 0.1uF filtering capacitor is fine to smooth the rectified pulses from the output. You never feed a regulated voltage to an LED since it sets its own voltage and its...
  6. Audioguru

    12V and 5v(USB) battery pack build. help.

    I buy Name-Brand American Li-PO battery chargers from my local hobby shop. They are made for radio-controlled models and do not cost too much.
  7. Audioguru

    12V and 5v(USB) battery pack build. help.

    A protection board is supposed to protect against high load current. This one doesn't. What about the extremely high charging current? A mother disaster. Why doesn't ebay say the manufacturer's name? A car is also dangerous. Would you buy a cheap Chinese no-name-brand car??
  8. Audioguru

    12V and 5v(USB) battery pack build. help.

    The very cheap No-Name-Brand Lithium battery charger and protection board from China is listed at 40A! Does it work? Will it cause an explosion and fire?
  9. Audioguru

    QW-ms305D setting constant current?

    Look on You Tube for a test of its current regulation NOT WORKING. The test person contacted the seller Who KNEW ABOUT IT NOT WORKING and gave a refund. Cheeep Chinese Junk!
  10. Audioguru

    Input power vs Output power in pro amps

    Since the very high power PRO amplifier is lightweight then its power supply also must use switching technology.
  11. Audioguru

    Input power vs Output power in pro amps

    Antique vacuum tube amplifiers did not produce almost double the 8 ohm power into 4 ohms then produce almost another double the power into 2 ohms. I also never saw a bridged vacuum tubes amplifier that produced massive power like this Crown PRO amplifier. The spec's for this amplifier are...
  12. Audioguru

    Input power vs Output power in pro amps

    In the User's Manual 175W is not shown anywhere. A photo of the highest power amplifier in this range shows its AC input at 425W and the spec's shows its total output of 440W into 8 ohms loads. Maybe it says in tiny writing, "or more depending on the load impedance".
  13. Audioguru

    Input power vs Output power in pro amps

    Harald, you are talking about "music power". The power supply in an amplifier is simple for it to have fairly good voltage regulation. A good transformer and a large enough capacitor. Peak power is simply double the REAL power. Very distorted power (overdrive) also doubles the REAL power...
  14. Audioguru

    Regulating output of a 5252f?

    I converted ALL of my many solar garden lights from a white LED to a colors-changing LED by adding a series 1N5817 Schottky diode in series with the LED and a 0.1uF ceramic capacitor parallel to the LED. The datasheet for the 5252 IC shows that the inductor sets the current. 150uH gives less...
  15. Audioguru

    Input power vs Output power in pro amps

    You cannot load extra amplifier power into a huge bucket then release it in a moment to get more power. But Snake-oil salesmen think they can doo dat. Crown amplifiers have a history with truthful spec's of continuous output power at fairly low distortion. Bridged into 4 ohms the power output...
  16. Audioguru

    Input power vs Output power in pro amps

    The manual clearly says the total output power is continuous with 0.5% distortion. That is true Watts power, not fake peak Whats. It produces 215W per channel into 8 ohms, 350W per channel into 4 ohms or 550W per channel into 2 ohms. When the 2 channels are bridged, its output is 700W into 8...
  17. Audioguru

    Woo-Woo LED Magnetic Lighting: Is it for real?

    There are lots of fake "Free Energy" videos.
  18. Audioguru

    1.5 volt bulb won't light in my circuit newbie

    Yes, a smaller resistance and smaller physical size. But the high current of 0.3A will quickly kill a little 9V battery, you will see the lights dim more and more as they kill the battery..
  19. Audioguru

    1.5 volt bulb won't light in my circuit newbie

    I remember Ohm's law the same way I remember how many fingers I have on each hand without calculating it using Algebra. 1) The total of my fingers is 10 due to luck (I played with chemical explosives when I was young but they all behaved like missiles. Guess what my missiles did?). 2) I count 2...
  20. Audioguru

    1.5 volt bulb won't light in my circuit newbie

    I don't use Algebra, instead I use simple Ohm's Law and simple Math Fractions. 1) What is the resistance of the white-hot bulb? It is spec'd at 1.5V/0.3A and OHM'S LAW is R= V/I. Then 1.5V/0.3A= 5 ohms. . 2) What value resistor will allow the bulb to work from a very strong 9V battery? This...
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