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JoshwaBurke 19th July 2012 06:31 PM

Active Filter Equalizer
Hey everyone,
I'm new to this forum but I'm working on a class project. I've tried multiple circuits from gyrators to chebyshev. Could someone help point me towards information on designing an Equalizer guitar pedal? Can it be done? I'm thinking using simple Low Pass and High Pass filters to make 3 Band pass filters. How do I create an AC signal with IC's from the 9V battery and have +/- 15 db per band?

The Equalizer Pedal will be powered using a 9V battery
A push button will turn the foot pedal on and off
A minimum 3-band equalizer will be used on the pedal (bass, middle, treble)
Low (Bass) center frequency band: 78Hz (5% tolerance)
Middle center frequency band: 1.15kHz (2% tolerance)
High (Treble) center frequency band: 7.8kHz (2% tolerance)
Equalizer Control will vary up to +/- 15dB per band

Any and all help will be much appreciated. I know the voltage sources are screwed up, but that's the simple bandpass circuit I want to use.

mickeymoose 20th July 2012 03:55 PM

As I am not a musician, I need to ask some questions:
1) If it is a foot pedal, how do you intend to operate the tone controls?
2)The frequency range of a guitar is 82 to 660 Hz (plus harmonics). Why the 7.8 kHz control?
Now download Duncan's "Tone Stack Calculator" and checkout some of the circuits at Elliott Sound Products - The Audio Pages (Main Index) lots of good info! E

JoshwaBurke 23rd July 2012 03:58 PM

1. The plan at the moment is to use linear taper potentiometers to help operate the tone controls. Not sure how I'll use them yet.

2. The harmonics and overtones theoretically go on forever but the human ear can only hear to a certain point. I looked at other guitar foot pedals (like the BOSS GE-7) to find some general frequencies others have used.

I'm taking a look just now at the website you sent me but it looks like it will be helpful! Thanks for taking the time to help me. =)

JoshwaBurke 24th July 2012 05:44 PM

Could someone help me figure out how to power the three bands I have in my multisim circuit now using a 9V battery? I can't seem to find anything on Google. I need to create an AC signal from the battery source. I also need to figure out how to connect the three bands to one output.

JoshwaBurke 24th July 2012 05:47 PM

Could someone help me find information on how to connect my three bandpass circuits to one output? I also need to figure out how to power the circuit using a 9V battery. Is there an easy way to create an AC signal from the battery?

JoshwaBurke 26th July 2012 12:25 AM

This is the what I have so far. Could anyone help me with having each band pass vary +/- 15dB per band.

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