Guitar Overdrive Effect Design

[SteveCPerrino]

I designed this circuit based off of a circuit I found online.

Before I buy all the parts, I wanted to ask you guys to see if this would work.

Please tell me if I did something wrong or if something would be a better option. Thanks!

I attached a picture of my schematic

The first two resistors and capacitors form high and low pass filters. The 2nd 1MΩ resistor is there to bias the op amp. The 47pF capacitor and the A100K Pot (Gain knob) form a high pass filter, and the 1KΩ resistor and .01µF capacitor connected to the gain pot form a low pass filter. The A100K Pot and the 1KΩ resistor also set the gain. In the output section, the 10µF electrolytic capacitor makes sure no DC voltage gets into the amp. After the 10µF cap, the A100K Pot and .005µF cap form a variable low pass filter (tone knob). After that comes an A100K Pot (volume knob), which also forms a variable high pass filter with the 10µF cap.

Again, please let me know if there's anything I should change, add, take out, or anything!

 

[tunedwolf]

I would choose a better opamp as the basis of an overdrive if I were you. Maybe a TL071/081, or for an even cleaner effect, an OPA21xx. Have you considered a discreet design perhaps using a small Mosfet gain stage to drive a JFET into saturation?
Not everything is best built with a "chip", this is especially true of audio projects.

rgds

 

[SteveCPerrino]

I could figure that out, honestly I'm fairly new to electronics so I just based this off of one I saw online, it's basically the same design except I cut out a hard-clipping stage and I changed some of the values

 

[#12]

Look up TS-9 Tube Screamer for ideas...Oh wait...here it comes now, and get rid of that crappy op-amp! A 4558 is an antique chip, but my guitar playing friend tried several modern op-amps in a TS-9 and preferred the original chip.

 

[Jon Wilder]

That LPF at the input is shelving at 160Hz @ 6dB per octave. Basically it would be letting all the lows through that you actually want to shelve out of the input circuit.

Failing to shelve lows out of the input circuit will result in bass distortion and we don't want that.

So I've redrawn the schematic that shows a reconfigured input. It's a HPF that shelves at 160Hz @ 6dB per octave to keep from distorting the bass frequencies a whole lot.

Also I've relocated the tone knob to the NFB loop. It basically controls how much of the highs get cancelled out via the NFB loop. 470pF was just an arbitrary value. You can experiment there to get the right tonal response from the knob.

**broken link removed**