passive overdrive

[jogina111]

I recently found a thing on
instructables about this passive
overdrive on guitar using
schottky diodes or cats
whiskers diodes with .15-.45v
voltage drop. Is there any alternative on these diodes
assuming that I cant find those
mentioned above?
Edit: ok, I am right...local shop
has dont have them. They only
got  1N4001 to 4000 diodes. Any ideas?

[darron]

any schottky diodes will do...it's a pretty crappy store if they don't stock a single schottky diode.

good examples might be 1N5819 or BAT85.



you could use some germanium diodes also. they will clip about half as much but will give you more volume on the output than schottkys as a trade off.

[jogina111]

yeah crappy shop. But what can I do? Its the only shop in my area.. 1N4001 to 47 are the only diodes available.

[darron]

well.. just had a quick look. can a hundred delivered to your house world wide for $2. could go into a passive overdrive business hehe


http://www.ebay.com/sch/i.html?_trksid=p5197.m570.l1313&_nkw=1N5819&_sacat=0

[Mark Hammer]

I wouldn't drive yourself crazy about this.  Even with Schottky diodes, the originators of this thing note that you need to have pickups with a powerful enough output.  If you have single coils, I wouldn't waste any time on it  If you have humbuckers or anything with an equally powerful output, you will get some clipping, but nothing anywhere near as consistent as what you'll get with a pedal which can apply additional gain to the guitar signal and ensure that the signal is well above diode clipping threshold for enough time to yield an audible overdrive.

[jogina111]

will the orange diodes on mobile phone chargers gonna work? They kinda look like Ge diodes..not quite sure.

[Mark Hammer]

While most Ge diodes we folks tend to see are glass, not all GE are glass, and not all glaass are GE.  You'll need to measure the forward voltage with a meter to positively ID the type, or else see the part number.

[Skrogh]

What a beautiful poem!

Sorry, I got next to nothing to contribute with, but the way your post was written made me read it like a poem 

A good thing to do is to put a socket, where you would have put the diode and try out some different ones.

[pinkjimiphoton]

if you pm me a snail mail addie, i'll send ya some diodes to mess with...shotkies, ge's etc.

that said...it doesn't sound all that great imho.

[jogina111]

suuure...pm me your address and Im gonna send you a good ol' snail mail..

[pinkjimiphoton]

well, if ya want me to send ya the stuff, i need YOUR snail mail, bud, lol...

[jogina111]

oh. Sorry here:  067 Concepcion Virac Catanduanes 4800 Philippines...

[analogguru]

just wondering:
Some time ago I learned, that there are passive comonents like resistors, capacitors, coils.
And then I learned, that there are active components like tubes, diodes, transistors, op-amps.
When I look at manufacturers catalogs, I also find the diodes listed under active components.

So how can an overdrive made with passive components (resistors, capacitors, coils ...) only ?
Or should it read "semi-passive", "semi-active" or "no-gain" overdrive when using diodes ?

analogguru

[artifus]

passive as in does not require an external power source to function. active does require a power source to do its thing.

cannot be semi passive - either it does require power to perform its intended function or it does not.

[jafo]

So how can an overdrive made with passive components (resistors, capacitors, coils ...) only ?

Use diodes to clip. Use resistors and capacitors to create filters before and after overdrive (both places sound different). You'll get an overdrive kind of sound, but since you're not driving anything, it isn't really overdrive.

[Jdansti]

I've built a passive diode clipper box using this as a guide:  http://www.muzique.com/lab/sat.htm

I set it up with a pot to control the amount of clipping and a rotary switch to select different diode types and symmetry. Two caveats, though:

1) You're guitar alone will not have the voltage necessary to achieve clipping.  This ONLY works if you place it after a high output effect.  That effect's volume needs to be set toward the upper end.  For example, you could place it after a preamp or compressor. Mine works pretty good when placed after my valvecaster. Think of it this way - some pedal circuits have a diode clipping stage on the output. I just put the clipping stage in a separate box.   

2) Each diode selection will alter the output volume differently.

[darron]

Schottky diodes should have a forward drop of about 100mv, so that should be plenty to get some clipping going right off a pickup. Maybe not if you have really thin sounding single coils or if you filter out too much bass with a cap. Won't work with regular diodes of course.

But yeah, with the signal drop out it causes it's pretty useless. Maybe you could think of it like a signal limiter?

Maybe somebody could scheme up a passive version of this with an input/output transformer to recover volume?

[jogina111]

where cam I cannibalize  schottkies, germanium or silicon diodes? I used a 1N4007 on my fuzzbox and I have to pick agressively to hear the fuzz so Im gonna change that diode to a better one

[3hree6ixty]

hey there,
I made a few of these and they're pretty so-so... If you want to try it yourself,
I'm from Singapore and those things are pretty cheap here... Those Schottky diodes (1N5818) are going for USD0.50 each and I bought a pile of 'em...
If you want, i could order and send it all over to you. and postage should be loads cheaper. Plus there's plenty of other parts here if any of you guys from this part of the world are having trouble obtaining them. Whatever Op-amps, tubes, diodes, LEDs, Capacitors, etc. any name, any values. There might not be a Radio Shack here, but we got a whole building here dedicated to electronics stuff like these... lol...

[petey twofinger]

http://www.instructables.com/id/Passive-Guitar-Overdrive-Black-Ice/

also :

http://www.cavepassivepedals.com.au/about.html

curious if anyone has tried the instructable / something similar , this all seems like it would very very Meh , but ?