Revised Audio Amp guide (updated 5-4-11)

[bentomo]

I revised the audio amp diagram I made, uses a lot less capacitors and saves a lot of space. It is also recommended to just wire a switchable headphone jack to it rather than using a signal to cut it off, saves tons of space.

http://i73.photobucket.com/albums/i208/MNDOGYDUDE105/revised.jpg

USE THIS ONE THE OTHER ONE MAKES RIGHT AUDIO COME OUT OF BOTH SPEAKERS! THANKS BUD!

http://i411.photobucket.com/albums/pp19 ... orbien.png

 

[bud]

Re: Revised Audio Amp guide

How is the quality?

 

[bentomo]

Re: Revised Audio Amp guide

Same, it's what I was testing, I couldn't notice a difference between any of the songs or gameboy games I tried.


Now use that extra money to buy some quality speakers.

 

[Snipeye]

Re: Revised Audio Amp guide

What range of speakers do you usually need/use? I know human hearing is from roughly 20Khz to 20hz, but how much of that needs to be produced by a speaker for it to sound good?

 

[brunoip]

Re: Revised Audio Amp guide

i really have to try it, thanks

 

[zeturi]

Re: Revised Audio Amp guide

Just to clarify, this is a stereo amp, right? It seems as easy to build as the mono LM386 amps.

 

[Snipeye]

Re: Revised Audio Amp guide

Stereo, correct.

 

[bentomo]

Re: Revised Audio Amp guide

I decided to revise it so it would be worth using one digital pot with this than 2 lm386's and 2 digital pots. Plus this is a higher quality amp.

 

[XCVG]

Re: Revised Audio Amp guide

It's probably better to drive headphones in SE mode- I don't know what long term effects driving them in BTL mode might have. I think I did something similar with a hacked amp though. It might be better to pull pin 17 high and drive the speakers in SE mode (tie the negatives to ground). Not sure what difference it will make though.

 

[bud]

Re: Revised Audio Amp guide

Bumpsorrybump

I noticed how it says it uses 4ohm speakers, can I use the 8ohm ones I have on hand?

 

[bentomo]

Re: Revised Audio Amp guide

I'm not sure, you can try them out without damaging them though.

 

[sinister1]

Re: Revised Audio Amp guide

They would work just fine. But would be about half as loud overall.

 

[brunoip]

Re: Revised Audio Amp guide

I'm pretty sure the amplifier wont work if you make it like that, here are some changes I made in order to make it work, the most important is the connection of the potentiometer because if you connect it like ithat you could make shortcut between GND and VCC.

regards, Bruno

 

[bentomo]

Re: Revised Audio Amp guide

Wow you've got it wired pretty small, nice job there.

Also the pot symbol I just drew so the person reading knows to wire it to power and ground, thanks for correcting that.


However the audio input goes in either 7 or 8, I've got mine wired to 7 and it works fine, I believe what it means by left negative audio input can be two halves of an analog signal, The way I have it wired works for me in the original drawing, so it probably works in either pin.

Thanks for the input.

 

[brunoip]

Re: Revised Audio Amp guide

Anyway I couldn't make it work with less than 8v, and the datasheet says that max V=6V, so I don't know whats happening there
What voltage did u use in yours tests?

 

[bentomo]

Re: Revised Audio Amp guide

That is definitely weird, I run my amp on 4.5 volts, and in my portables I run it off of the 7805 on the n64.

 

[bud]

Re: Revised Audio Amp guide

NVM

 

[bud]

Re: Revised Audio Amp guide

I'm confused bump

I am way unclear on how to wire the potentiometer. I have been looking at schematics and there are several ways to do it. D:

I have a standard pot with 3 terminals. Could someone look at the diagram and tell me how to wire it correctly?

Thanks.

EDIT: (16:481) grossaffe: according to the diagram, you need the voltage in connected to the Vin terminal, the ground to the ground terminal, and then Vout to pin 18

Grossaffe, I luvs you.

 

[brunoip]

Re: Revised Audio Amp guide

 

[bud]

Re: Revised Audio Amp guide

Thanks for the illustration bruno.

Everything thing is working fine now except for the left speaker. The right speaker sounds great but I get absolutely nothing from the left one. Ive quadruple checked my wiring and tried 3 different speakers with no luck. Any ideas to what could be causing this?