Music, Programming, and other topics related to the modern Music Engineering Scene.

Op-Amp Circuit Mods

First, I must apologize for the huge delay in posts. College has kept me very busy as of late. With the end of the semester comes a few more posts.

We left off with op-amp circuits. These are all well and good, but they could use a few extra add-ons. Two really common things you can do both involve capacitors. The first is called a DC-blocking cap. Basically, put a capacitor before and after your op-amp circuit. Why? Because op-amps run off of a DC voltage, right? This means your audio signal gets biased to halfway between the rails of your op-amp. This extra DC voltage can cause a hum, which the addition of capacitors will eliminate. Pretty handy trick, eh?

The second use of capacitors is known as an "anti-squeal cap." Put a capacitor in parallel with your feedback resistor. Only the high frequencies will make it through this capacitor, which means you get more negative feedback for higher frequencies. More negative feedback means more attenuation, thus creating the "Anti-squeal" effect. Nothing too crazy here, we want to keep this circuits nice and simple... for now.

Don't worry. I've got plenty more to talk about over the next few weeks. Thanks to the break between semesters, I'll have plenty of time for new posts. So fear not! I haven't forgotten. We'll delve into some seriously cool issues in the posts to come.



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