tubbytwo Posted November 24, 2005 Report Share Posted November 24, 2005 All schematics show an 8 Ohm speaker. Any change in parts to use a 4 Ohm speaker? Quote Link to comment Share on other sites More sharing options...
audioguru Posted November 25, 2005 Report Share Posted November 25, 2005 Hi Tubby,The datasheet shows how inefficient the LM386 is with a 4 ohm load.It can supply only a whopping (hee, hee ;D) 300mW to a 4 ohm speaker with fairly high distortion.With a 6V supply. it would get hot at only 300mW output.With a 9V supply, it would be even hotter but the max output power of only 300mW doesn't increase.Find a more powerful amp IC. Four ohm speakers are used in cars. Philips and ST Micro make about 140 amp ICs for cars. I use a National Semi amp IC that is obsolete now but it drives my 4 ohm speaker to 4.8W at very low distortion with a 7.2V supply. ;D Quote Link to comment Share on other sites More sharing options...
tubbytwo Posted November 25, 2005 Author Report Share Posted November 25, 2005 Hey thanks. I use 8 Ohm speakers, but was just curious. It drives a small 4" speaker for a xtal radio. Works just fine. Quote Link to comment Share on other sites More sharing options...
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