Search results

Search Forums New Posts
  1. Audioguru

    Bypassing TV's internal speakers to home-made aux input

    $1000 speakers? The sound system I use for my TV cost me $25.00 brand new and it has distortion so low that my audiophile ears cannot hear it. It is advertised at having 150W (fake Whats) of output but inside it the power transformer is rated for 9VAC/1.1A (9.9 Watts). I figure 1.5W goes to each...
  2. Audioguru

    Bypassing TV's internal speakers to home-made aux input

    The hiss disappeared because the Ground Loop Isolator cut off the highest frequencies. It is difficult to hear the quality of the sound since the "rock" music has a high amount of intermodulation distortion (fuzz). I don't know how much too loud are the headphones when connected to the speaker...
  3. Audioguru

    Digital music player with a Tivoli Audio Model One

    The TPA3110D2 datasheet says it can drive one 4 ohm speaker in mono with both its amplifiers paralleled and shows a graph of its maximum output power at different supply voltages and it overheats if its output power is 30W or more when its supply is 17V or more. If an 8 ohm speaker is used then...
  4. Audioguru

    Info for 2N3904 and 2N3906

    Pinouts were mentioned: 1) Most small American transistors have a 2Nxxxx part number and have a pinout that is EBC looking at the flat face with the pins downward. 2) Most small European transistors have a BCxxx part number and have a pinout that is CBE (see, the reverse of the American ones)...
  5. Audioguru

    Bypassing TV's internal speakers to home-made aux input

    You did not understand that the speaker amplifiers are bridged amplifiers. A bridged amplifier is two amplifiers, one amplifier for each speaker wire. Then the red speaker wire has one amplifier and the black speaker wire has another amplifier. The amplifiers are connected out-of-phase so that...
  6. Audioguru

    Head lamp set up

    I see most cars today have 4 front lights. The low beams are near the outside and the high beams are nearer the middle. Many drivers do not know anything about high beams because they drive day and night with the high beams on. Other drivers do not know that daytime running lights are usually...
  7. Audioguru

    Bypassing TV's internal speakers to home-made aux input

    I was thinking about scraping off some green to expose some copper then I saw this solder joint:
  8. Audioguru

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    You said you had -1.5V on pin 4 of U3 a while ago. Then it jumped up to +3.8V or something and pin2 also had a voltage too high. Then you removed the U3 IC which caused the U3 pad 4 voltage to drop to +0.3V or -0.3V instead of -1.5V. Now you have U3 installed and its pin 2 is too high at +0.92V...
  9. Audioguru

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    You keep saying that the negative supply is actually positive 1.5V. It might be causing U3 pin 2 voltage to be too high. The polarity problem is caused by the diodes D5 and D6 that have been connected backwards or they are Chinese and they are marked backwards. Maybe the Chinese pcb is labelled...
  10. Audioguru

    Light chaser

    A CD4017 lights only one LED at a time. It will never make them all stay on. You can "inhibit" the clock then the LED that was lighting stays turned on and the remaining LEDs will all be off. To switch them all on you would need two diodes for each LED, one of the diodes from the CD4017 and the...
  11. Audioguru

    Is it possible to replace keyboard LEDs with neon indicators and a single inverter?

    An NE-2 neon bulb operates from 60V to 90V through a current-limiting resistor of about 100k ohms. Then it is a string. Many strings can be connected in parallel. Simply use a 100k resistor in series with each neon bulb and use a 120V inverter.
  12. Audioguru

    What type of wire is copper wrapped around fluffy threads?

    The red is enamel insulating paint. I don't know if heat or a solvent removes it from the ends for connections.
  13. Audioguru

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    1) Pin 6 of U3 is low because its - input voltage is higher than its + input voltage. But its - input voltage is too high. 2) Did you unsolder one wire of R21 and measure its 10k resistance? 3) Always connect the black meter probe to the negative wire of C1. Then -1.5 should show -1.5V, not...
  14. Audioguru

    Bypassing TV's internal speakers to home-made aux input

    The + wire of very old capacitors was marked "+" but modern capacitors have the - wire marked "-----".
  15. Audioguru

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    I see a few problems with your voltage measurements:
  16. Audioguru

    Bypassing TV's internal speakers to home-made aux input

    with an output of only 3W the output voltage is puny so 16V, 25V or 50V capacitors would be fine.
  17. Audioguru

    Bypassing TV's internal speakers to home-made aux input

    The value of a coupling capacitor depends on the speaker impedance it feeds and the lowest frequency you want. The formula is C= 1 divided by (2 x pi x frequency x impedance) so assuming your headphones are 32 ohms and you want to hear low frequencies down to 30Hz the capacitor value for each of...
  18. Audioguru

    help -- muh logic ended in ruins

    A Cmos oscillator is made with a single Schmitt-trigger inverter, a resistor and a capacitor. 6 of these inverters are in a CD14106, CD4584 or MM74C14.
  19. Audioguru

    Bypassing TV's internal speakers to home-made aux input

    Every TV is different but many modern audio products use bridged amplifiers. There is no need for a dual polarity supply for a bridged amplifier because the speaker has no DC across it. Most car radio amplifiers are bridged and they do not use a dual polarity supply. Texas Instruments make many...
  20. Audioguru

    help -- muh logic ended in ruins

    A Mosfet is an amplifying transistor. Since a CD4069 inverter is low current Cmos it does not conduct hundreds of mA and get hot but it can be biased at half the supply voltage and be an amplifier. Here is an example where the inverter has a 10M negative feedback resistor and a 1k input...
Top