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  • ESPsupport
    replied


    You will need to remove the internal speaker and connect your external one to the same pads. The speaker should be 8ohms of at least 1.25 watts.

    Note that the -ve speaker terminal is not GND.

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  • ploto
    replied


    Hello
    with uLCD43PTC, where (pin) i can connect an (instead of internal) with 8 ohm and watt ?

    Thanks in advance

    Leave a comment:


  • Bryan
    replied


    Hi Capricornone,

    Reading through your recent post, sadly it is not possible to get the raw PWM. Also, the output signal on the audio I/O pin on the 30 way header is filtered beforehand. This filtering makes the signal an analog rather than a raw PWM.

    The most practical and feasible solution would be to have the output signal fed to an external amplifier to attain the objective of putting up the sound. A simple USB powered amplifier will surely do the trick. Also, simply using an external amplifier will greatly reduce the possibility of damaging the device.


    Best Regards,

    Bryan

    Leave a comment:


  • capricornone
    replied


    mm...okay, did a little more research on amplifiers, I don't think a Class D would be much simpler, was just hoping to be able to drive the speaker with a single transistor, but I don't think that's possible.

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  • capricornone
    replied


    Ah, this makes sense.

    So, next question. I noticed the Audio Output pin is outputting a filtered analog line level signal, is there a simple amplifier that can be built using this output? Is there a reason for this kind of output instead of the raw PWM signal, which would be easier to amplify with a Class D amplifier circuit?

    Leave a comment:


  • Bryan
    replied


    Hi Capricornone,

    wouldn't I be effectively putting 4 ohms on the output of the driver? Unless, I disconnect the onboard speaker?

    :: Yes. The addition of another 8 ohm speaker in parallel will result to a 4 ohm output load. In this regard, it is also best to consider requirement of the chip driving the audio, that is- to have a minimum of 8 ohms as output impedance. (reference: TPA6205A1 audio power amplifier).

    I'd like to hook up a slightly larger speaker to the module but didn't want to supply my own amplifier, unless there's an easy way to do that...
    ::I'm afraid that there are no other ways around it. Hooking up a new speaker (without any amplifier) will produce a sound a little louder than the built-in speaker but it does not add to the output power of the audio driving chip (TPA6205A1). This means that if you would require a louder output sound then using an audio amplifier would be the only way.

    Best Regards,
    Bryan

    Leave a comment:


  • capricornone
    started a topic external speaker

    external speaker

    Hi, maybe a dumb question, but if I hook up an external speaker (8 ohm) to the speaker outputs of one of the picaso display modules, wouldn't I be effectively putting 4 ohms on the output of the driver? Unless, I disconnect the onboard speaker?

    I'd like to hook up a slightly larger speaker to the module but didn't want to supply my own amplifier, unless there's an easy way to do that...
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