Drive 20 ohm 1 watt speaker with LM386 module gs26347

Thread Starter

skpatra22

Joined Aug 11, 2019
15
Hi

I have a 20 ohm 1 watt speaker which I want to drive using mp3 player module FN-M16P.
I tried running it using the Speaker pins directly it did not work. It did not work using the DAC pins input to the GS26347 and trying to drive the speaker.
Please give me some idea if it's possible to make it work.

Attaching the few images and screenshots.

Any suggest will be helpful.
Thanks.

Regards
Susanta
 

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to3metalcan

Joined Jul 20, 2014
263
Posting a picture of your actual build would be more helpful in checking your work. Sans that, a few thoughts:

1) have you tested the speaker with another sound source to verify that it's good?

2) Have you verified that you actually have data loaded on the FN-M16P?
 

Thread Starter

skpatra22

Joined Aug 11, 2019
15
Hi to3metalcan,

Thanks for your response.
Yes I have tested both the amplifier and the mp3 module and both the speaker pin and the DAC pin.

I have not tested the speaker as I have no other way to test it.
Could you kindly let me know how I can test.
I don't have any other amp or ckt to test the speaker.

But do 20 ohm speakers exist. I couldn't find on web.

Any help is greatly appreciated.

Regards
Susanta
 

to3metalcan

Joined Jul 20, 2014
263
You should describe the tests you did to determine that the mp3 module and amplifier are good.

Speakers exist in all kinds of different impedances, though 20Ω is uncommon. One way to test it would be to take a low-voltage battery and see if it makes a sound when you **briefly** connect the battery terminals to the speaker terminals. Don't leave it connected or the speaker's coil could get hot (and then the speaker will be dead, even if it isn't now!)
 

be80be

Joined Jul 5, 2008
2,395
Where did the 20 ohm speaker come from
The datasheet said 4 to 8 ohm 3 watt
1.2. Product Features  Supports MP3 and WAV decoding.  Supports FAT16 and FAT32 file system.  24-bit DAC output and supports dynamic range 90dB and SNR 85dB.  Supports AD key control mode and UART RS232 serial control mode.  Supports maximum 32GB micro SD card and 32GB USB flash drive.  Supports maximum 3000 audio files in the root directory of the storage device.  Supports maximum 99 folders, and each folder can store 3000 audio files(only first 255 files is valid when the serial command is sent to play one of the audio files in the folder).  Supports advertisement insertion.  Supports random playback.  Built-in a 3 watts amplifier that can direct drive a 4ohms/8ohms 3 watts speaker.  30 levels adjustable volume, and 6 levels adjustable EQ.
http://www.flyrontech.com/uploadfile/download/20184121510393726.pdf
 

Thread Starter

skpatra22

Joined Aug 11, 2019
15
You should describe the tests you did to determine that the mp3 module and amplifier are good.

Speakers exist in all kinds of different impedances, though 20Ω is uncommon. One way to test it would be to take a low-voltage battery and see if it makes a sound when you **briefly** connect the battery terminals to the speaker terminals. Don't leave it connected or the speaker's coil could get hot (and then the speaker will be dead, even if it isn't now!)
Thanks again to3metalcan.
Tried with a 1.5 v aaa and a 3.7 volt battery. No click sounds. So does it prove that the speaker is dead. :-(
 

Thread Starter

skpatra22

Joined Aug 11, 2019
15
Where did the 20 ohm speaker come from
The datasheet said 4 to 8 ohm 3 watt


http://www.flyrontech.com/uploadfile/download/20184121510393726.pdf
Thanks be80be for your reply.
I have one lying around from one of my friend.
Wanted to use it with the mp3 player.
I have also tried it using the gs26347(LM386 Module). It can support upto 16 ohm. Wanted to know if it can be used with the LM386 module.
I am a novice. Seeking help from the pro like you.

Thanks in advance.

Any help is appreciated.

Cheers.
 

LesJones

Joined Jan 8, 2017
4,511
If you want to get 1 watt into your 20 ohm load (Speaker.) then you need about 4.5 volts RMS (Square root of 20 ohms x 1 watt.) 4.5 volts RMS is 4.5 x 1.414 x 2 = 12.73 volts peak to peak. So for a single rail amplifier you need a supply voltage of at least 12.73 volts. In practice you need a bit more than that to ensure the output transistors are not driven into saturation. You would need to run the LM386 near it's maximum voltage rating of 15 volts.
 

Thread Starter

skpatra22

Joined Aug 11, 2019
15
If you want to get 1 watt into your 20 ohm load (Speaker.) then you need about 4.5 volts RMS (Square root of 20 ohms x 1 watt.) 4.5 volts RMS is 4.5 x 1.414 x 2 = 12.73 volts peak to peak. So for a single rail amplifier you need a supply voltage of at least 12.73 volts. In practice you need a bit more than that to ensure the output transistors are not driven into saturation. You would need to run the LM386 near it's maximum voltage rating of 15 volts.

Thanks Les Jones
Makes sense.
I will drop the plan and head off to get a 8/4 ohm speaker.

On another note which speaker is better 4 ohm or 8 ohm.
I am going for a 3 watt one.

Thanks.
 
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