LM386 Stereo Headphone Amp - Dual Output Possible?

[TheNewGuy]

Is that why when I had connected Pin 6 only with an LED and the rest I had followed the schematic in the datasheet for normal gain of 20, the LED used to flash and dim to the music. I had thought it was cool, but apparently not!

 

[audioguru]

I don't know what your LM386 was doing.

 

[TheNewGuy]

Uh oh...that must be baaaaad.

He he, just kidding.

I have a couple LED's laying around, so I'm trying to find out how to use another LM386 to blink LED's to the music, like you said in the other thread.

Do able?

 

[Dragon Tamer]

was your LM386 connected so that the current had to flow through the LED before it went through the 386?

 

[TheNewGuy]

no it was connected after the first lm386 before the point at which the .05 ceramic cap connected to pin 5

 

[audioguru]

You were shorting the output of the LM386 with your LED. An LED needs a current-limiting resistor in series.

The output pin 5 of an LM386 has DC which will light an LED continuously. You can bias the input with DC so that its output is low without a signal and it goes high to light a current-limited LED with a signal. But then it cannot drive a speaker properly.

 

[vmsa]

I think that the TDA2822 is very good amp for headphones.

 

[transistor495]

That horizontal blue colored cap I've seen in very old goodies..

If you're good(not bad) soldering expert, and know well or having a dedicated mind to execute on adequate component placements..then with the help of a little patience, you can build hundreds of working little amplifiers like that daily(handmade). It is that simple!

Another thing is right component selection. I'd say 2822 is a minimal choice for that Creative goody...

 

[Dragon Tamer]

i understand what you're saying now new guy. thank you for clarifying in chat. what you want is a circuit that can flash the LED at higher volumes rather than having it dim. if that's the case then you can try a setup like the one i showed you yesterday, or you can wait a little while and i will give you 2 complete circuits that should both work. the problem, is that like audioguru said, you're going to get a serious reduction in sound quality. you can fix this by using another 386 that is coupled with your first one.

and for the record, i agree, the 2822 is a good amplifier.

 

[Dragon Tamer]

i have made these circuits, hope they help.

 

[audioguru]

i have made these circuits, hope they help.

They are missing the very important Zobel network (0.05uF capacitor in series with 10 ohms to ground) at the output which prevents the amplifier from oscillating. Every circuit on the datasheet has it.

 

[Dragon Tamer]

duely noted, i made the scematics based on the circuit i had built, that little capacitor and resistor somehow managed to stay hidden.

 

[Hero999]

I don't know why people bother incorrectly copying schematics from datasheets when they can easily copy and paste which is guaranteed to be right.

 

[Dragon Tamer]

it was a slightly different configuration