Add Diode-Clipping Distortion to your Guitar Amp

Step 5 Other options...

Although I chose an on / off / on circuit, the amount of distortion can also be controlled by simply adding a POT. Now the effect can be adjusted, and the desired asymmetry "dialed in." It should be noted that I've add a fixed "mix control" to mine--the two resistors. But a variable control might be of value....

And there are many diode types we haven't covered: zener, silicon, other LED colors, etc. Even MOSFET transistors have a voltage drop.

Flipping the asymmetry--switching the directions of all the diodes, will also have an effect. This can emphasize odd or even harmonics. Choose whichever sounds best to you.

There are a great many variations of diode clipping circuits. Here are a few links to get you started... :
-- DIY Fever: Diode Clipping
-- MOSFETs as diodes
-- AMZ - Diode clipping staturation controls
-- AMZ - "Warp" controls--balancing diode clipping
-- AMZ - Mosfets and Zeners as clipping diodes

Comments

[GatedSound]

I'm confused at the wiring to the lugs of a pot. Which are the diodes attached to, and which goes to the signal?

[gmoon]

The "wiper" (the arrow) is always the center tab of any POT. Here you see that goes to the signal path.

The other two tabs are identical for linear POTs, other than effecting the direction (whether resistance changes up or down, right or left.)

Log or audio POTs also have a taper, so greater "change" is bunched up on either side. They'll have to be tested in the circuit.

Check out those AMZ links (Step 5) on saturation and warp controls for more options...

[Lenny24]

I've Used A Zener Diode in my Diode-Clipping Circuit. It doesnt' Work really good, but that could beause I only used a LM741 as "Preamp Stage", and then a 1-Watt-Amplifier-IC out of Old PC-Speakers. I Attached the Diodes after the 1Watt Amp and Put an 10K Resistor after that and Connected it to an Old Guitar amp (That hasnt' OD). I also tried Retifier-Diodes. That Worked a lot better.

[gmoon]

That sounds about right. Thanks for the info!

[Lenny24]

No Promblem! ;)

[magnus0]

What pot should I use? Linear or logarithmic?

[gmoon]

To some extent it might depend on the diode biases--if each side is radically different, then log. But I'd bet on linear 98% of the time. You'd be well served to checkout the AMZ Warp link above....they've got more variations you should checkout.