[SOLVED] Elementary question about the audio amp on a BBC B

discuss both original and modern hardware for the bbc micro/electron
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JasonStonier
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[SOLVED] Elementary question about the audio amp on a BBC B

Post by JasonStonier » Thu Sep 17, 2020 9:06 am

So, the Beeb has an onboard mono audio amp, and the speaker in mine is 8Ω.

Does anyone happen to know if the amp can safely drive a 4Ω speaker? Reason for asking is I have two nice little 8Ω speakers I want to use in a case mod, and I can either wire them in parallel for 4Ω or series for 16Ω. I think at 16Ω they'll be too quiet - if I put them in parallel I can add a 4Ω resistor in series to bring it back up, but just wondering if that's necessary.
Last edited by JasonStonier on Thu Sep 17, 2020 11:27 am, edited 1 time in total.

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Diminished
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Re: Elementary question about the audio amp on a BBC B

Post by Diminished » Thu Sep 17, 2020 10:47 am

IIRC the audio amp is an LM386. Data sheet here. Seems to suggest 4 to 32 ohms is an acceptable range.

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JasonStonier
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Re: Elementary question about the audio amp on a BBC B

Post by JasonStonier » Thu Sep 17, 2020 11:24 am

Perfect, thanks for the help. Confirmed it's an LM386N.

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