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Часть обзора переведена автоматически.

  • 28/02/2018

    The amplifier has differential (bridge) outputs so can provide approaching 10 volts peak-to-peak swing on a 5 volt supply. The data sheet for the XPT8871 (via Google search; in Chinese) claims 5 Watts into a 2Ω load and 3.5 Watts into 3Ω load. However graphs in the data sheet show more like 1.5 Watts (with 10% distortion). Note the chip is supposed to shut itself down if it gets too hot. The data sheet says it's compatible with the LM4871, for which a data sheet is available in English. However pin 3 of the XPT8871 controls mode (AB or D) whereas for the LM4871 it is a differential input. On the amplifier board, pin 3 is held low so the amplifier is class AB. The gain is about 62x (36dB). Unfortunately there is no provision for setting the gain with a feedback resistor to the chip's input. With my limited test equipment, the upper 3dB frequency of the amplifier board is surprisingly high, about 100kHz, but the lower 3dB frequency is about 350Hz: OK for speech but disappointing for music. Attached photo shows output with 500Hz square wave input. Note only one of the two pins labelled "IN" is the input; the one towards the supply connections is a second ground connection. The circuit diagram on the Banggood website is not the circuit of the amplifier board: it's taken from the XPT8871 data sheet. It's a little surprising that the board is not supplied with pin headers. Of course the amplifier board is amazing value from Banggood.

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  • 14/06/2018

    Not good, not bad. I tried to pluged a stereo signal to this mono amp (with 1k resistor on each input signal). Sound saturate easily. But it may comes from my power supply, my mini speakers. I'm not an expert so I can't say (and don't listen to me)

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  • 19/07/2018

    Came in odd packaging but the product came safely

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  • 15/06/2018

    Товар соответствует описанию.

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  • 07/11/2017

    muito bom

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  • 19/06/2017

    good quality mini amplifier..

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  • 09/06/2017

    Seems to bee good preamp for a price

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  • 28/01/2021

    Они хорошо работают усиливая электронный сгенерированный звук, как ошибки звуков.

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  • 19/06/2018

    Acheté dans l’idée de faire une enceinte autonome cet ampli fait très bien ce qu’on lui demande. Il ne faut pas s’attendre à un rendu extraordinaire il y a un souffle bien présent. De même attention à l’alimentation qui risque de perturber le fonctionnement de l’ampli. Sur la carte il n’est pas évident de souder les fils et il faudra y aller à tâtons quand à la polarité du signal d’entrée puisque rien n’est indiqué (on le voit de suite quand le + est sur le - : on a un souffle/buzz omniprésent) Un bon outil qui dépannera (et donnera une nouvelle jeunesse aux vieilles enceintes ou autres projets DIY). NB : Il semblerait que l’ampli ne consomme pas assez pour être branché seul sur une batterie externe USB (elles finissent par s’éteindre au bout de quelques secondes) Je pense qu’en rajoutant une led ou quelque chose du genre afin de tirer un peu plus de jus ça devrait rentrer en ordre.

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  • 29/03/2019

    Just what I needed for a project. Test: 0.14 V P-P produces 8.76 V P-P output V gain = 62.5. Flat up to 40 kHz, usable to over 100 kHz. Didn't measure noise or distortion, looks good on a scope.

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