Creating a "clipping" pedal

[triskadecaepyon]

I was wanting to create a clipping pedal the clips off the harsh highs in my distortions.  The clipping that I am looking for is the type that occurs in amps that "clip" with gain, and/or a preamp that does it also.  Should I be using diodes, resistors, or capacitors? I can't afford a tube preamp.

[R.G.]

was wanting to create a clipping pedal the clips off the harsh highs in my distortions.

That's a little confusing. Clipping pedals usually *create* highs. Whether the highs created are harsh or not depends on the nature of the clipping and the pre-clipping and post-clipping filtering. See "The Technology of the Tube Screamer" at GEO for an example.

I think you might mean "filtering" to filter out some of the harsh highs.

Or perhaps something else. Can you elaborate? What is your amp, your distortions, etc. that you are getting harsh highs from?

[triskadecaepyon]

Those terms kinda run together in my head too much, sorry.  What I mean is if you take a ds-1 through the clean channel, it "shrieks" too much instead of a warm distortion.  However, when I put it in the dist/overdrive channel, and add just a small amount of gain, it sounds smoothed out, like a tube preamp would do.  Basically, I am looking for the effect of a "tube warmth".

[Lurco]

The use of POD, Line6, or similar modeling preamps have been propagated much here, lately (joking  :oops: )

[petemoore]

What kind of amp?
 The DS-1 mods are at Fuzz Central, I need to order the 5532 SIP Chips for mine from Mouser for the DS-1 I got a couple days ago, [and also  4558's].
 The chip that's in it, has been reviewed as having 'different' sounding [harsh?] high end content.
 Another first mod I'll probly try 1rst-ish is  add a small Pf capacitor across the clipping diodes, this removes some of the high end content, and will probably let the tone knob be set higher and = highs with less harshness..
 The mods stated probably make an excellent overall choice for most users, especially since there is a tone knob.

[triskadecaepyon]

well my DS-1 is modded from the fuzzcentral website, I just want to find a way to smooth it out, that's about it.  If you were asking about the amp, it's a Crate MXR15

[R.G.]

I think that your amp has a lot of treble cut in the distortion channel. That's common, expecially for solid state amps.

You could, as Peter suggests, put a cap across the clipping diodes. I wouldn't use a few pf. I'd stick in a 0.01uF and work up or down from there to taste.

[Mark Hammer]

I suspect RG is spot on.  I've spent some time looking through SS amp schematics as of late, and the distortion/dirty channels are usually quite different than the clean channels.

Although Commander Keen is correct in suggesting a cap in parallel with the  clipping diodes, I find that fizziness in distortion is often a product of shallow filtering.  What I prefer to do is use multiple filtering interventions to tame the fizz.  So, rolling off more of the highs in earlier boosting stages in the pedal (there are 2 such places in the DS-1) will result in less higher-order harmonic content.

Alternatively, the issue or solution may lie in the tone control for you.  The DS-1 has a Big Muff style tone control, which pans between a lowpass and highpass filtered version of the clipped output.  The lowpass version may well be too muted for some, but of course when they turn the tone "up" a bit, it gets too strident and loses too much bottom. The solution here may be to change the cap in the lowpass section so that when turned fully counterclockwise (tone turned "down") it produces a nicely "rounded" version, rather than a muffled one.  You lose the existing degree of tonal contrast presently available, but if it gets you the sound you want/need then you're in business.

The cap in question is C12, with a value of .1uf.  It can be found at the wire end of the board almost exactly midway between the side edges.  In tandem with the 6.8k resistor, it forms a lowpass filter with a rolloff around  234hz, which is kind of low.  You can certainly introduce more treble by turning the tone control, but that treble is unrestrained and sure to be buzzy/shrieky.  Try replacing C12 with a .033uf cap.  This will give a rolloff around 700hz.   A .027uf cap will yield a rolloff around 860hz.  These may be in the right zone for getting a "rounded off" growl when you turn the tone way down.  If you still get too much buzz and shriek, then try upping C10 from its current value of .01uf to maybe .015 or .022uf.

Please note that the tone control WILL seem to produce less variation afterwards.