Here are some 555-used-for-PWM circuits...
http://musicsynthesizer.com/Corpse/VCEOM.html
http://musicsynthesizer.com/DIY/Grant/CVtwister.html
This isn't a 555, but it uses PWM to do some tricks to control voltages. The PWM "VCA" is used for crossfading in this case. PWM is good to get vary linear voltage control of a control voltage. The problem with this circuit is that the 21kHz triange will only give you about 10kHz bandwidth. If you would run audio through this, it wouldn't sound too nice. This is a Buchla control voltage processor, from the 200 series modular synthesizer.
http://musicsynthesizer.com/Buchla/b257.jpg
GET BACK TO WORK!!!
I'd hate to see this thread die.
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http://musicsynthesizer.com/Corpse/VCEOM.html
http://musicsynthesizer.com/DIY/Grant/CVtwister.html
This isn't a 555, but it uses PWM to do some tricks to control voltages. The PWM "VCA" is used for crossfading in this case. PWM is good to get vary linear voltage control of a control voltage. The problem with this circuit is that the 21kHz triange will only give you about 10kHz bandwidth. If you would run audio through this, it wouldn't sound too nice. This is a Buchla control voltage processor, from the 200 series modular synthesizer.
http://musicsynthesizer.com/Buchla/b257.jpg
GET BACK TO WORK!!!
I'd hate to see this thread die.
mark