PR17B - Voice Recording and Playback

[altan]

Hi,

Is the speaker output of the LM386 amplifier suppose to be very distorted when I increase the gain? Although the volume will be louder but its very distorted. At 0 ohm for the amp gain , the sound quality is ok but it is very soft compared to directly connecting the speakers to the ISD chip.

Somehow when I directly connect the speakers to the ISD speaker output the sound quality is better compared to the amplifier chip. Even if the volume isn't very loud but the clarity is very good.

Both the mic and audio input doesn't have any problem.

Any solution or suggestion to change amplifier IC?

Regards.

[robosang]

Er..... the DIY that record and playback the voice? There is amplifier in it? Last time don have. I think they improved it!

Anyway, normal amplifier circuit will amplifier every signal including noise, I think that's is the problem. Good amplifier circuit will be expensive and complicated.

[altan]

Ya, its an improved design and it recently came out a few months ago...

BTW, I already found a solution to it when referring to the LM386 datasheet.

By default the amplifier has a gain of 20 but by adding a 10 uF capacitor across pin 1 and 8 the gain is increased to 200. It sounds better now but the distortion still occurs when the amp gain variable resistor is increased.

The distortion I mean refers to the sound at certain frequency becoming distorted not referring to the background noise.

[robosang]

Oh That's great! Good to hear that, should have recommend to Cytron, changing the value of capacitor should be easy.