Martin,

I am assuming your amp is ready You just need to lower the volume
not amplify. If you like to amplify too then use op amp and put photo
resister as feedback resister. 

Andre Abelian 




-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
Of Hector Martin
Sent: Saturday, May 07, 2005 1:01 PM
To: Microcontroller discussion list - Public.
Subject: Re: [EE]: PWM for volume control

Andre Abelian wrote:
> Hi to all,
> 
> Remove the opto-coupler and connect your audio directly and 
> use pwm thru opto resister to change the resistance this will
> lower the volume.
> If you do not have opto resister make one take small tube
> one side add led and the other side photo resister. 
> 


But I also want to *amplify* the sound, not just attenuate the
existing volume (which is pretty low)

-- 
Hector Martin (hector@marcansoft.com)
Public Key: http://www.marcansoft.com/hector.asc

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