Schottky 1N5819 Diode

[candyflipper7]

I came across an old thread here about the Schottky diode being used as an on board distortion device like the sugar cubed, over priced "BLACK ICE" circuit. How many is used to create a very mild distortion as I know from research the "BLACK ICE" has 4 different distortion levels. I am not a very huge distortion kind of guy. I would be interested in trying a diode on a push pull pot if this is possible to have distortion on pulling up and a regular (or) multiple tone cap(s) in the down position connected to a 2 pole 6 "or" 5 position switch. I also saw that JohnH had sound clips on the thread I was reading. They are gone now for some reason along with an unknown diagram or something. Does anyone know how I could possibly look at this original thread? Or even better if anyone has tried this and how in the heck do I solder a diode to a push pull pot. How many do I need to achieve a very mild distortion?

Also, here are (2) links to other diodes recommended:

www.mouser.com/ProductDetail/STMicroelectronics/BAT41/?qs=sGAEpiMZZMvAvBNgSS9LquujaTxtlB93

"or"
www.mouser.com/ProductDetail/Central-Semiconductor/CDSH270/?qs=RS415aRcUaHmAK4dLoxIJA%3d%3d


If posting links is frowned upon, I apologize sincerely.

[jerry]

Ok, a few comments here:

First, this is just my opinion, but I have not found any diode by itself that has given me a satisfying or good sounding distortion. I'm originally a circuit design engineer, so you can imagine how many different kinds of diodes I've tried over the years just so I could have switchable fuzz built into my guitars. I also own a Black Ice and am also not happy with that.

Second, there are many different "colors" of distortion from a soft fuzz often used in blues just to make things a little gritty to a hard, brittle distortion favored by many for heavy metal, and everything in between. You'll not have much control over the intensity or tonal aspects of the distortion from a diode in your guitar.

The reason for all this is that the diode only starts to distort the output signal when that signal exceeds the diode's cut-in voltage and begins to conduct and clip the upper part of the signal waveform -- below that level, it has no effect. And that's part of the problem. Hot pickups will work best for this because they'll put out about a half volt signal, some, a little more. Most pickups put out less.

Germanium diodes will cut in around 0.2 - 0.3 volts depending on the diode and some Schottky diodes will kick in around 0.2 volts. But the most common diodes, silicon, won't cut in until about 0.6 - 0.75 volts, so they won't even work on the output of most unamplified guitars. Distortion effect boxes amplify the signal before sending it to a diode or instead create distortion digitally using a modeling algorithm. The digital modeling approach offers the most control.

I hope this helps and I'm sorry if this dashes your hopes to implement distortion through use of a diode in your guitar. Of course, diodes are very inexpensive, so there's absolutely no harm in trying this out for yourself. I just didn't want you to get your hopes high, spend a lot of time installing a diode in your guitar, and then be very disappointed.

f you d decide to try this, create a little extension signal cord between your guitar and amp into which you can insert some different diodes so you can gauge the effect for yourself. If you find something you like, then you may consider actually installing it more permanently.

Good luck!

[candyflipper7]

TY Jerry. It is always great to get input and advice from someone who has tried this over years and has expertise on the subject. I did read things not so great about the Black Ice Circuit. That's pretty much why I was willing to give it a try the cheap way first. So either way a couple of dollars is no big deal and I can test it out for myself. I really appreciate the advice on the thread. Thanks for tips on the hook up also.

[JohnH]

This is a thread about Shottkys as diode clipping

guitarnuts2.proboards.com/index.cgi?board=modules&action=display&thread=4787&page=1

Includes sound clips

They do work, but are more of a curiosity IMO, rather than something one would want instead of more active forms of distortion.

To try one, a single one with a pot, wired as if it was a tone cap is as good as anything.

I think that to describe a diode for this application, just in terms of a cut-off voltage, misses some of the truth. The Schottkys actually do mess with your signal all the way down to zero in their forward direction.

Diodes are better described as having a logarithmic relationship between current and voltage. If you plot this out for a normal diode, and relate current and voltage to an effective resistance, you get some very high impedance's below about 0.6-0.7V and so a normal silicon diode sounds very clean across a guitar unless you get a big signal, when you get a brief and unpleasant break up clip.

But the Schottkys, if I recall correctly from some tests I did, are travel ling through a range of around 50k to 100k as voltage changes around 0.2V, still a log relationship but right in the zone where it affects a guitar pickup. So you can get some gritty decay all the way to zero.

Interesting, but it still doesn't mean it sounds any good.

Diodes, including Schottkys, make a clearer effect after some active buffer or preamp (hear in the tests linked above). But if you do that, then you have effectively made one of the classic simple distortion circuits - no rocket science there.

John

[jerry]

Jan 14, 2013 21:39:08 GMT -5 JohnH said:

I think that to describe a diode for this application, just in terms of a cut-off voltage, misses some of the truth.

CF, John's statement quoted above is well stated: music really is about what we hear rather than what we can measure. The only way to determine whether simple diode distortion appeals to you is to experiment with it and I didn't mean to imply otherwise. I included the small discussion about cut-in voltages so you could better understand how different diodes work and how those differences can limit effectiveness in this kind of application.

[sumgai]

flipper,

And jerry was being modest in his tech discussion... ;D

The others have stated it correctly - the Schottky has a lower threshold voltage in order to turn on or 'cut in', but the trade-off is, it switches between conduction and non-conduction much, much more quickly - on the order of a thousand times faster. For our purposes, this translates to harshness - it's either present, or it's not, no in-between at all.

In general, all diodes will exhibit this property in unpowered circuits - they switch far too quickly between on and off (and back again), the time it takes to switch is at least several hundred thousand times, if not millions of times, quicker than the audio range of frequencies.

The only viable way around this is to introduce a third element into the junction of the semi-conductor, making it a transistor of some sort (or a tube, if we're gonna be generous about it). Now we can control the exact amount of time spent in one region or the other, meaning is it conducting or not. I'm sure you've guessed by now that this is what stompboxes do, unless they're expensive and use modeling.

For all that digital and modeling does and can do, analog is still cheaper, easier to monkey around with, and to most players, better sounding. Not always true, but by and large.....   In the end, powered analog (battery or wal-wart) circuits are the best solution when Tone is one's top priority. But if Tone is not first on the list, then by all means, personal experimentation is the name of the game! ;D

HTH





sumgai

[candyflipper7]

TY all for the input and data I added this mini toggle to my guitar with a diode and cap. I am using a push pull tone pot with caps on it also. I think I am having no effects with a 500k tone pot. Maybe 250 k I will some change?

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