What rectifiers should I use?

[Mpp]

Hi, I'm building this pedal-

The guy who wrote the guide to building it said you could use rectifier diodes for a metal sound (he also said you could use LEDs, but should avoid using them if you're a beginner).
So I'm a beginner and don't much of anything about diodes. What do you think I should use?

[anotherjim]

I suspect he meant a diode like 1N4001, which is a pretty generic "rectifier diode". Of course, all diodes ARE rectifiers, but these particular ones are commonly used to rectify AC to DC in power supplies. They work ok as distortion clippers.

Another common diode type for the job is the "signal/switching diode". These are for small current work. Common ones are 1N4148 and 1N914. These are very commonly used in distortion effects.

LED's will work, but not so much. They take more voltage to act so will only clip and produce fuzz with strong playing. Ordinary Red LED's will probably be the best variety of LED for the job. If you fit LED's it will work more like an overdrive to your amp. Other diodes will fuzz easier, but will limit the volume of the effect and can be quieter than the "clean" guitar sound. LED will be louder.

The "go to" guitar distortion diode, for a long time, are the Germanium types due to lower voltage requirement (will work on lower signal level) and smoother response. Types like 1N60, OA97 etc. Germanium will also be quieter than other kinds.  You will only get germanium diodes from a specialist suppler or e-bay.

You can also try different mismatched diodes, such as LED for one and 1N4148 for the other. A common ploy is to try different combinations. I would encourage you to do just that - find what works best for you.

[duck_arse]

I was going to say exactly all that ^ , but was too slow.

I would have added - head over to AMZ and look for the clipping and warping pages - and - "welcome to the forum", though.

[Mpp]

You can also try different mismatched diodes, such as LED for one and 1N4148 for the other. A common ploy is to try different combinations. I would encourage you to do just that - find what works best for you.

I'll probably do this thanks

[turdadactyl]

Give this a read:
http://www.diystompboxes.com/pedals/diodes.html


And this:
http://www.generalguitargadgets.com/how-to-build-it/technical-help/articles/design-distortion/

[Mpp]

thanks

[Transmogrifox]

I wonder why the instructions say not to use LED's if you're a beginner?  It seems to me that messing with clipping diodes is one of the most beginner-safe modifications for experimentation.  LED's are among the list of viable clipping diodes.

As for typical rectifier diodes, the main characteristic I think is uniquely different from small signal diodes is a much longer reverse recovery time.

I wonder if this places a fast 'blip' coming out of clipping on each polarity.  This could sound like having some kind of sharp harmonics that tend to go well with metal tones.  That sort of effect would make it cut & shred a little bit more.  To my ears the difference between diodes is subtle (except for the non-subtle output volume change between different forward voltages). 

Things like 2 diodes forward, 1 diode backward is a lot less subtle.  I can definitely hear the difference with those types of combinations.

[samhay]

^LEDs are not as tolerant of heat as the other usual clipping diodes. If you are learning to solder they may not survive the experience.

[Mpp]

part of the reason he said not to use LEDs if a beginner was because of the fact that they have no indication of which end is which

[bluebunny]

part of the reason he said not to use LEDs if a beginner was because of the fact that they have no indication of which end is which

Not so.  The cathode is (usually) identified by the flat side, and the anode has the longer leg:

[GibsonGM]

^^   Yeah...it ONLY takes about 2 years for a beginner to remember that, tho, LOL!  ( at least THIS beginner!)

As long as they are opposed...."make sure one flat spot goes up, and the other goes down..."

Welcome, Mpp!

[bluebunny]

No-one said I remember this stuff!  I had to look at the picture before I wrote the words!   

[Mpp]

Thanks guys that's actually pretty easy

[deadastronaut]

experiment with all kinds of diodes....its fun. 

welcome btw..