What can you use for clipping diodes

[paulyy]

So what does everbody like to use for clipping. Sillicon, mosfet, NPN transister, Ic's, LED's or what ever that can be used for clipping. Just trying to get some ideas for a clipping section Im working on for my next project. Thanks.

[Joe Hart]

People use all of those. The main thing is the clipping threshold. The higher the threshold (with all else being equal) the less clipping will occur. This will result in less distortion and less compression. A lower clipping threshold will result in the opposite.  Hope this helps.
-Joe Hart

[paulyy]

Thanks for the info. It does help but Im not looking for so much about the info but more on what you can use inplace of the clipping diodes. Just want to use something different instead of the more common ones to use like 1N400x, 1N914, germanium, led's, yadda yadda yadda. Example: Iv used tubes inplace of the clipping diode in a SD1 and it worked. Is there anthing odd that somebody has used out there.

[R.G.]

Well, you could make some copper oxide rectifiers by cleaning some bits of copper sheet and then oxidizing one surface with a propane torch flame and laminating a few of these together. Or you might be able to find an old selenium-iron rectifier. Or you could try to make point contact diodes with galena crystals. All of these will probably have forward voltages less than the voltage of germanium. Even aluminum, very clean and suspended in an appropriate aqueous solution will exhibit diode operation.

For extra credit, mine and refine the selenium, copper or aluminum. 

[CynicalMan]

Homemade tunnel diode? Even better?

[Mark Hammer]

It's not at all clear that any and all diode substitutions or alternates will lead to sonic differences that are either audible, or differentiable from the simple impact of changing the forward voltage.  I think that is the gist of RG's missive, and something I would concur with.

This is not to say that there are no differences in diode behaviour, but one needs to keep in mind that the spectral coverage of your average guitar signal and guitar amp speaker is but a teeny tiny weensy fraction of the spectral coverage that diodes are intended to remain linear in.  Since diode behaviour is partly a function of the current reaching it, one if probably going to have far more luck extracting different sorts of sounds by means of varying that current than by monkeying around with alternate diode types. 

[amptramp]

You can use an ideal diode which is a diode within an op-amp feedback loop that has a very sharp breakdown at zero volts.  Look up:

http://www.national.com/an/AN/AN-31.pdf#page=1

and on page 17 you will find an ideal diode and an ideal clamp.  The clamp in conjunction with a variable series resistance will give you settable clamping voltage and resistance with no variation over temperature.  Use two of them, one for the positive and one for the negative part of the waveform.

[CynicalMan]

According to a guitar amp book I have, "Resistor diode ladders can be used to replicate almost any imaginable transfer curve."

[stringsthings]

Well, you could make some copper oxide rectifiers by cleaning some bits of copper sheet and then oxidizing one surface with a propane torch flame and laminating a few of these together. Or you might be able to find an old selenium-iron rectifier. Or you could try to make point contact diodes with galena crystals. All of these will probably have forward voltages less than the voltage of germanium. Even aluminum, very clean and suspended in an appropriate aqueous solution will exhibit diode operation.

For extra credit, mine and refine the selenium, copper or aluminum. 

is that what devo was singing about in "working in a copper mine?"   

[TimWaldvogel]

If you wanna work on this project awhile you can just walk around the house an start throwing things in the feedback loop !! Unfolded  paperclips. Unfolded paperclips wrapped in aluminum if you like that 'tinny tone'... Just shove some leads from resistors in there sticking straight up and connect them with a razorblade for a more 'sharp' tone

[paulyy]

Lol! You guys are pedal making Macgyver's. Didnt think I would get that kind of responce

[stringsthings]

i'm working on a Big Muff Pi circuit this week ... and i'm gonna use red and green LED's ....  just to be silly  ....

on a more serious level, i put together PAiA's Quardrafuzz a long, long time ago and it uses LED's for clipping .... they even light up slightly as you play ! ....

[paulyy]

i'm working on a Big Muff Pi circuit this week ... and i'm gonna use red and green LED's ....  just to be silly  ....

on a more serious level, i put together PAiA's Quardrafuzz a long, long time ago and it uses LED's for clipping .... they even light up slightly as you play ! ....

I notice they get more intence when you start playing harder. I always thought that was kinda neat how that works. I heard useing different colors led's will change the it clips. Not sure if thats true but I guess I would have to try it to find out

[amptramp]

i'm working on a Big Muff Pi circuit this week ... and i'm gonna use red and green LED's ....  just to be silly  ....

on a more serious level, i put together PAiA's Quardrafuzz a long, long time ago and it uses LED's for clipping .... they even light up slightly as you play ! ....

Nice effect, but LED's act as photodiodes (leaky ones at that) and ambient light will change the clipping threshold.  This means that if you are playing under fluorescent lights, the luminosity variations will modulate the LED current, causing hum.  Put the LED's inside of the box and drive a slave LED if you want to see the clipping.

[stringsthings]

yeah ... i don't really want to see the clipping LEDs .... it's just for gut shot purposes ... 

[Renegadrian]

I notice they get more intence when you start playing harder. I always thought that was kinda neat how that works. I heard useing different colors led's will change the it clips. Not sure if thats true but I guess I would have to try it to find out

yeah, high brightess blue 3mm I have sound different from standard 5mm red LEDs. The firsts are more on the "compressed" side, while the last ones have lotsa volume and less compression.

[paulyy]

I notice they get more intence when you start playing harder. I always thought that was kinda neat how that works. I heard useing different colors led's will change the it clips. Not sure if thats true but I guess I would have to try it to find out

yeah, high brightess blue 3mm I have sound different from standard 5mm red LEDs. The firsts are more on the "compressed" side, while the last ones have lotsa volume and less compression.

Crazy! I may just have to make a clipping section with just different color led's.