Componets of lm386 to amplify isd1820

MrChips

Joined Oct 2, 2009
27,651
104 is the value marking on a component.
It is not be used in a schematic diagram.

If the component is a capacitor it is shorthand for 10 x 10^4 picofarads, or 100nF or 0.1μF.

LM386 is a poor choice for a general purpose signal amplifier.
 

WBahn

Joined Mar 31, 2012
27,854
Hello, i try to understand what capasitors and resistors i need to use lm386 to amplify isd1820 signal. What is “ 104” ? It cannot be 104 farad. And is 4.7 o , 4.7 ohm?
You asked this same thing in another thread. Please confine questions to one thread.
 

Audioguru again

Joined Oct 21, 2019
5,406
The ISD1820 can already drive an 8 ohms 0.5W speaker, but there is no detailed datasheet showing its output power.
With a 6VDC supply, an LM386 produces only 0.2W to 0.25W in an 8 ohms speaker. With a 9VDC supply, an LM386 can produce 0.5W to 0.6W in an 8 ohms speaker. Very low loudness.

The low capacitance of the capacitors in your LM386 circuits cut low audio frequencies, producing tinny sounds.
 

Thread Starter

sotiraw

Joined Nov 5, 2022
8
104 is the value marking on a component.
It is not be used in a schematic diagram.

If the component is a capacitor it is shorthand for 10 x 10^4 picofarads, or 100nF or 0.1μF.

LM386 is a poor choice for a general purpose signal amplifier.
What would you recommend? The sound from isd1820 is already much disapointing so any suggestions there also are welcome
 

Thread Starter

sotiraw

Joined Nov 5, 2022
8
The ISD1820 can already drive an 8 ohms 0.5W speaker, but there is no detailed datasheet showing its output power.
With a 6VDC supply, an LM386 produces only 0.2W to 0.25W in an 8 ohms speaker. With a 9VDC supply, an LM386 can produce 0.5W to 0.6W in an 8 ohms speaker. Very low loudness.

The low capacitance of the capacitors in your LM386 circuits cut low audio frequencies, producing tinny sounds.
i tried the isd1820 and the sound is really low, i can barely hear it.
 

Audioguru again

Joined Oct 21, 2019
5,406
Maybe you damaged the SP+ and SP- outputs of the ISD1820 by wrongly shorting them or wrongly connection one or both to 0V.
Maybe your speaker is not 8 ohms or is too small. Maybe your speaker is not properly in a speaker enclosure.
 

Thread Starter

sotiraw

Joined Nov 5, 2022
8
Maybe you damaged the SP+ and SP- outputs of the ISD1820 by wrongly shorting them or wrongly connection one or both to 0V.
Maybe your speaker is not 8 ohms or is too small. Maybe your speaker is not properly in a speaker enclosure.
no nothing of this has happened. I have used before this component. I know its limitations. If its wasnt with so low output then its producers wouldnt need to add to the datasheet a way to enchance the sound. Do you have an actual suggestion on some simple circuit to gain some volume?
 

Audioguru again

Joined Oct 21, 2019
5,406
The datasheet for the ISD1920 does not say its maximum speaker output power and does not say its maximum output sensitivity. The datasheet shows an LM386 low power amplifier connected with small capacitance values that kill its low frequencies.

But the LM386 amplifier has a mid and high frequencies signals voltage gain of 20 times!
Then although the maximum output power of the LM386 is low and is probably the same as the maximum output power from the ISD1820, the output level from the LM386 is 20 times more because of its voltage gain.

The datasheet of the ISD1820 mentions using the old Toshiba TA7368 amplifier that produces less maximum output power than the ISD1820 but it has a voltage gain of 40dB (100 times)!
It also mentions using the old Motorola MC34119 amplifier that produces a max output power of only 0.3W into a 32 ohms earphone but is voltage gain is adjustable and is more than 100 times!
Use the LM386 amplifier circuit that I copied from its datasheet to gain some volume. Its datasheet shows that adding one 10uF capacitor to pins 1 and 8 increases its voltage gain to 200 times!
 
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LowQCab

Joined Nov 6, 2012
2,620
The first question is how LOUD do You want it to be ?

Lots of Volume requires lots of Power, (not just Voltage-Gain ).

A detailed description of how You intend to use this Recorder is required information,
otherwise everybody is just guessing at what You want.

How far away must this Recording be heard ?
Will it be used in a quiet, or a noisy environment ?
Will it be used outside ?
How large is the Speaker that You want to use ?
What type of Power-Supply do You want to use ?
Does the Recording need to be as clear as possible ?, or is some heavy-Distortion acceptable ?
.
.
.
 
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