Diodes influence on sound.

[Hendrik1]

What are the differences in sounds between the different kind of Diodes available today.

I know for example when I did make my first Cristal radio I had a fat black Vintage Germanium diode that did works best, I offered a complete tube radio to make it, my father wasn't pleased.

Someone experiment with this with Stompboxes?

[darron]

this is talked about over and over. i'm surprised the geniuses here havn't all jumped in for their say, maybe they are sick of answering this type of question.

in erms of clipping and distortion, germaniums are supposed to clip faster, and because of this they give a smoother distortion. electronics shops sell newly produced germanium diodes, so you don't have to go NOS or vintage. of course, silicon isn't as rounded, and clips a bit harsher. people also like using LEDs these days (which I havn't tried). i THINK(?) they are supposed to clip the roughest, and will also give the loudest output. does that sound right guys? they will emit based on voltage also, so they will glow to your guitar strumming if you want to mount them visibly.

i'd be interested in some posts on this topic too!

[GibsonGM]

Looks like you covered it pretty well, Darron...
Using Ge diodes results in a smooth, rounded, 'overdrive-ey' sort of sound.  (Stones)
Si gives you a pretty tough & dirty sound (Guns N Roses, generic hard rock)
LEDs vary by forward voltage...color does matter!  They're gritty and buzzy (grungy); I don't care for them, would just use a fuzz pedal for this sound.

They all sound a little different if you play with the input/output caps and tone stack, which will also affect how they clip.  AMZ has AWESOME ideas about differential clipping schemes....

Ge diodes will result in a lower output level, followed by Si and LEDs in order of loudness.  This is because the 'excess' signal after you cross their threshold is grounded.  Theoretically, different Vf's in the same type of diode will result in different sounds, so experiment to customize.  I haven't seen LEDs glow in use this way, but that may just be because I haven't hit them with a hot enough signal. 

Which reminds me - they will also all sound different depending on how much signal you send them...my MXR Dist+ sounds pretty generic at level = 4;   at level = 8, the thing overloads my tube amp;  opamp clipping, si diode clipping, and tube clipping together is INSANE!!!  Not a function of the diodes, but worth mentioning...

[powerplayj]

Build a Dist+ and socket the diodes......  I just built this and this circuit would be the perfect study for your question.

[darron]

the best thing to do would be to get one of those dials to select between 4 different sources of diodes. 4p4t switch that looks like a potentiometer.

[Izzy]

So which are the best diodes to use for Heavy metal, Shred kinda tone?

Beside 1n4148?

Is there any?

[Peter Snowberg]

So which are the best diodes to use for Heavy metal, Shred kinda tone?

Beside 1n4148?

Is there any?

I would say any silicon diode, but much of that "metal" tone comes from the filtering before and after the diodes.

[Izzy]

Can you give me one eg?


Hmm....So for metal it would be better if I shunt diodes to ground after the opamp rather than in feedback loop, right?



Would putting more diode in a series give more distortion?
Like 3 Si diodes shunt to ground on each side?

[darron]

i reckon metal as really harsh sounding, so try some leds? fuzz and transistor drives add a bit, so you might even want to fuzz something up then put some led clipping after it? that should sound awesome.... but again, id say that it'd be EQ'ing for etc. for a large part. for example, i used the same 1n4004's in a RAT pedal and in a ts808. the change wasn't much from the original, but each pedal has a totally different tone.  the rat is a bit metally actually...

[Izzy]

hmm  ok

So does anybody knows how to add a Mid boost using knob?

[petemoore]

  I think J Orman might have something in the AMZ Labs Notebook you want to take a look at.
  Mid boost using knob: HP and LP Filters and a volume knob to attenuate [output will be lower  than input]
  "Boosting a frequency isnt' really done, it's 'faked'...
  Get rid of the frequencies you don't want 'boosted' then boost whats left.
  A bandpass midhump can be messed with by reducing lows [with a cap in signal path] and reducing highs [cap from signal path to ground] this can be made adjustable with caps or caps and pots, and can take out...even all of the audible signal [if caps 'overlap' hi and lo cut frequencies] what's left can be boosted [and often must be to attain unity again].
  Starting with a gain circuit, add *small cap to signal path from ground..or larger cap with a pot on it [see schematics and AMZ LN etc.], then make the input cap a smaller value, this will cut highs/lows, what is left is mids, boost that.
  Perhaps you want a more sophisticated Tone Control circuit.

[aron]

this is talked about over and over. i'm surprised the geniuses here havn't all jumped in for their say, maybe they are sick of answering this type of question.

Well, they have answered the question in the FAQ in hopes that newbies will read it.   

So does anybody knows how to add a Mid boost using knob?

Check out the Shaka Express:

http://www.diystompboxes.com/wiki/index.php?title=Featuredpedals

[col]

Some time ago Adam Horrel put a link to his degree dissertation on this subject where he built a circuit and trailled different types of diode and tested the differences both aurally and physically. He evaluated their use for different types of music comparing them to 'standards'. It was very interesting and if you use the search function it might still be there. If not try to find his name and pm him to see if he's prepared to e-mail you a copy. I found this one of the easist to understand and practical evaluations of the different diodes that I've read.
I also did an experiment when I'd just started building pedals and built the electra distortion attached to a six way switch to choose between six different sets of diodes. The ones which sounds best to me were LEDs! By the way, LEDs do light up faintly when used for clipping but you'd only see it when the lights are off and it's only at the peak of the note.
If you are reading this Adam, then thanks for an interesting and informative read.

Col

[WGTP]

Results will vary depending on the type of circuit.  If the diodes are in the feedback loop, they will limit the amount of distortion the op amp contributes when maxed out.  If the diodes go to ground like a Dist+ the op amp will contribute a significant amount of distortion, prior to the diodes.  For a given distortion level, GE diodes will contribute more to the distortion and the op amp less.  For the same distortion level with LED's, the op amp will contribute more.  You end up with more of a 2 stage distortion IMHO.  Of course, there are many different combos, LED/GE, 2SI/1SI, etc.  You become obsessed with it, so be warned.