From: legg@nospam.magma.ca   
      
   On Mon, 08 Dec 2025 07:07:22 -0900, Christopher Howard   
    wrote:   
      
   >Hi, I had some LM386 chips on hand, and I downloaded the LM386 Low   
   >Voltage Audio Power Amplifier data sheet (Rev C).   
   >   
   >https://media.digikey.com/pdf/Data%20Sheets/Texas%20Instruments   
   20PDFs/LM386.pdf   
   >   
   >I built, on a breadboard, the minimum part count application on page 8   
   >(Figure 10, section 9.2.1), except that I got rid of the 10k volume   
   >control resistor on pin 3, and I replaced the speaker with a 4 ohm   
   >resistor. Am using a 6V supply for pin 6, and feeding in test signals of   
   >about 5 kHz, amplitude 100 mV RMS.   
   >   
   >I'm finding, though, that — unless I ground out the input — that however   
   >I tweak the input frequency or amplitude, I still get garbage output.   
   >The output looks like some kind of complicated sum of many saturated   
   >signals of various frequencies.   
   >   
   >Does anybody have thoughts on where I might have gone wrong, to guide my   
   >troubleshooting?   
   >   
   >I re-checked my pin connections a few times, and the component values,   
   >which are reasonably close. I replaced the LM386 chip once as well, and   
   >got the same results.   
      
   Per fig 03:   
      
   6V supply, 4R load - maximum ppk output is typically less than 3V.   
      
   With Av=20 and 100mV rms input, you're asking for 5.65Vppk on the   
   output.   
      
   RL   
      
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