Help to run external speaker for my mp3 player

[jeolex]

Dear friends,

I have a mp3 player that need 3.7 V. I hacked it and remove rechargeable battery. I will run with via external power supply.



I have 3W 4ohm speaker, mp3 player and 3.5mm male jack. So I have wired the speaker and jack, but there was not enough sound. So I need to supply speaker by external power. How to be wire connection and how many amps I need for valuable sound from speaker.

 

[KlausST]

Hi,

You need an audio amplifier.
Suplied with DC power, MP3 signal input, speaker at the output.

Klaus

 

[Audioguru]

Your speaker is tiny and has no enclosure so it will not play bass sounds in music if you operate it from an amplifier.
Recently at Costco I heard the demo of a new Bose small wireless, portable Bluetooth speaker/speakerphone and it sounded fantastic for its small size. It costs $159.99US.

I play my computer and TV from a Sylvania 2.1 sound system that sounds good. It cost $17.50US on sale.
In the ad it says 150W. On the box and owner's manual it says 75W RMS. On the power label it says 75W (so it is 100% efficient!). Inside it has a small power transformer labelled 9VAC/1.1A (9.9W).
The amplifier is probably 50% to 60% efficient but might be a modern class-D switcher that is 90% efficient.

Its amplifiers are two 16 pins DIL ICs with a small heatsink glued on.
One IC is probably a stereo amplifier feeding 1.5W to 2.0W real Watts to each 4 ohm satellite speaker.
The other IC is probably bridged and feeds 4.0W to 5.0W real Watts to the 6 ohm sub-woofer.
So the total output power is 5.5W to 7W.

Each satellite speaker has two 1.5" speakers with foam surrounds and the "soft-dome tweeter" is not a speaker but is actually a vent covered with a soft dome.
The sub-woofer is a 5" long-throw speaker with a foam surround in a pretty big wooden ported enclosure. It lights up with 6 blue LEDs.

The amplifier and power supply are built into the sub-woofer enclosure and has a volume control and bass and treble tone controls.

I have played it loudly for hours and it doesn't smoke. I have never heard its amplifiers clipping. I tested its frequency response and it plays from 40Hz to 18kHz smoothly and very well.

 

[zlatkoMM]

Maybe this small picture will help you ...

 

[jeolex]

It was so clear. I just wonder that what if my mp3 player have not enough power output for speaker. I mean is it possible to wiring the same adapter to speaker as well as mp3player without amplifier. What is amplifier duty exactly ?

 

[Audioguru]

Your MP3 player is designed to drive an amplifier or earphones (about 0.08W maximum output). The amplifier must be powered by a battery or an AC/DC adapter but with only 5V its output power will be fairly low.
A cheap clock radio produces about 10 times the power (0.8W). The power supply in the Sylvania computer speaker system I showed uses 12VDC and the total maximum output power from all three amplifiers is about 6W.

 

[c_mitra]

Maybe this small picture will help you ...

It will be wise to show the power connections to the power amplifier. Speakers, the output devices in the audio power amplifier, are basically current devices and high power speakers need considerable current to drive.