You removed the 1k resistor and capacitor that filter power to the mic. Then when there is some audio, the battery voltage will jump up and down a little, which enters the input of the amplifier and is amplified 200 times, then going around and around producing a putt, putt, putt, putt sound.
Why do you have two 100uF capacitors parallel with the battery?
You will not notice when the extra 0.1uF capacitor at pin 3 is replaced by a piece of wire because the simple calculation with 1 divided by (2 x pi x the capacitor x resistor values) show that it cuts low frequencies below 32Hz.
The headphones ad shows absolutely no detailed specs. 20Hz to 20kHz is missing the deviation. Plus and minus 20dB is terrible. Plus and minus 3dB is hifi. Also the very important impedance is not stated.
To attach something, I click on Attach Files, browse for my file and click open, then post my reply and it automatically becomes a thumbnail like this:.
You had it almost correct before.
Now the 1k resistor is missing that is part of a filter that feeds the 100uF capacitor to smooth the power feeding the mic's 10k resistor.
Before the 100uF capacitor parallel with the battery was 1000uF but the circuit will work fine with 100uF until the battery voltage gets low.
The LM386 already has an internal resistor at pin 3 so the 100k resistor is not needed and the extra 0.1uF input capacitor also is not needed.
You will be sorry that the volume control is missing. A motorcycle or jet airplane will deafen you and might destroy the earphones.
An earphone or speaker can have its resistance measured with a multimeter. An earphone with a 32 ohm impedance will measure about 28 ohms.
Then the two earphones in parallel will measure 14 ohms DC which will be 16 ohms impedance.
You draw the earphones in series instead of in parallel. Then they will sound odd because they will be out-of-phase.
I do not draw schematics with a dark grey background. Instead I copy the datasheet and paste it into Microsoft Paint program. I also copy and paste other parts to add to the 1st copy.
NEVER connect earephones in series, then they will sound odd because they will be "out-of-phase". If both ears hear sounds the same (yours don't) then try it.
Why are you still using those awful old earphones? They were made for old fashioned shortwave AM radio with a response from 500Hz to 2kHz if you are lucky. Humans with normal hearing can hear from 20Hz to 20kHz like half decent modern recordings, headphones and speakers.
Since you are not listening to hifi music down to 20Hz or earthquakes down to 1.69Hz, then calculate a capacitor cutoff frequency of 30Hz or 40Hz, certainly not 1.69Hz. C= 1/(2 x pi x 30Hz x 2k ohms)= 2.7uF.
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