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Adding low-level audio output/

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  • Dave C
    An LCD monitor has tiny (and tinny!) speakers and no audio output connections. Is adding low-level (1v p-p I think is standard?) audio output as simple as
    Message 1 of 32 , Jun 22, 2014
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      An LCD monitor has tiny (and tinny!) speakers and no audio output connections.

      Is adding low-level (1v p-p I think is standard?) audio output as simple as adding series resistors between the audio amp (at the solder pads for the speaker connections) and the new output jack?

      This is to drive common amplified desktop speakers.

      Thanks,
      Dave
    • alienrelics
      Andy, you said everything I didn t have time to type in. Thank you. Well, one more thing... there is also the matter of predictability. I know that 10k/100
      Message 32 of 32 , Jun 27, 2014
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        Andy, you said everything I didn't have time to type in.

        Thank you.

        Well, one more thing... there is also the matter of predictability. I know that 10k/100 voltage divider is going to attenuate by -40dB for any reasonable input impedance. IE, anything with an input impedance of >=1k with that divider will be no more than 10% off. If you want some adjustability, a 10t 1k pot between the two would do.

        With a single series resistor, I -must- measure the AC impedance of the inputs in order to select the resistor. Any variation in input impedance is going to cause a nearly equal variation in attenuation. So twice the input impedance, half the attenuation. I've seen input impedances vary between 1k and 100k, although those are the outliers. Also, if you want adjustability, you'll need a very high resistance trimpot.

        It isn't like we're worried about small amounts of distortion, or loading down the speaker amplifier outputs.

        And as stated, if it is line level input, you can probably get away with no attenuator at all.

        Steve Greenfield AE7HD
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